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The information in this prospectus is not complete and may be changed. These securities may not be sold until the registration statement filed with theSecurities and Exchange Commission is effective. This prospectus is not an offer to sell nor does it seek an offer to buy these securities in any jurisdiction where the offer or sale is notpermitted.

SUBJECT TO COMPLETION DATED JULY 18, 2018

PRELIMINARY PROSPECTUS

            Shares

Common Stock

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        This is the initial public offering of our common stock. We are offering all of the shares of common stockoffered by this prospectus. No public market currently exists for our stock. We expect the initial public offering price of our shares of common stock will be between $            and$            per share.

        We have applied to list our shares of common stock for trading on The Nasdaq Capital Market under thesymbol "ARDS."

        We are an "emerging growth company" as that term is used in theJumpstart Our Business Startups Act of 2012, or the JOBS Act, and, as such, elect to comply with certain reduced public company reporting requirements for future filings.

        Investing in our common stock involves a high degree of risk. See "Risk Factors" beginning on page13.

        Neither the Securities and Exchange Commission, or SEC, nor any state securitiescommission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

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(1)

We refer you to "Underwriting" beginning on page 183 of this prospectus for additional information regarding underwritingcompensation.

        We have granted a 30-day option to the representative of the underwriters to purchase up to                        additional shares of common stock solely to cover over-allotments, if any.

        The underwriters are offering the common stock as set forth under "Underwriting." Delivery of the shareswill be made on or about                        , 2018.

Cantor

   

        The date of this prospectus is                        , 2018

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        You should rely only on the information contained in this prospectus. We have not authorized anyone to provide any information or to make any representationsother than those contained in this prospectus or in any free writing prospectus prepared by or on behalf of us or to which we have referred you. We take no responsibility for, and can provide noassurance as to the reliability of, any other information that others may give to you. The information contained in this prospectus is accurate only as of the date of this prospectus, regardless ofthe time of delivery of this prospectus or any sale of our common stock.

        You should rely only on the information contained in this prospectus. No dealer, salesperson or other person is authorized to give informationthat is not contained in this prospectus. This prospectus is not an offer to sell nor is it seeking an offer to buy these securities in any jurisdiction where the offer or sale is not permitted. Theinformation in this prospectus is accurate only as of the date of this prospectus, regardless of the time of delivery of this prospectus or of any sale of these securities.

        Through and including                        ,2018 (the 25^th day after the commencement of thisoffering), all dealers effecting transactions in these securities, whether or not participating in this offering, may be required to deliver a prospectus. This is in addition to a dealer's obligationto deliver a prospectus when acting as underwriters and with respect to their unsold allotments or subscriptions.

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RISK FACTORS

        An investment in our common stock involves a high degree of risk. You should give careful considerationto the following risk factors, in addition to the other information included in this prospectus, including our financial statements and related notes, before deciding whether to invest in shares ofour common stock. The occurrence of any of the adverse developments described in the following risk factors could materially and adversely harm our business, financial condition, results of operationsor prospects. In that case, the trading price of our common stock could decline, and you may lose all or part of your investment.

Risks Relating to Clinical Development and Commercialization of Our Product Candidates

If we fail to successfully complete clinical trials, fail to obtain regulatory approval or fail tosuccessfully commercialize our product candidates, our business would be harmed and the value of our securities would decline.

        We must be evaluated in light of the uncertainties and complexities affecting a pre-commercial biopharmaceutical company. We have not completedclinical development for any of our product candidates. Our three lead product candidates are AR-301, AR-105 and AR-101. We expect to initiate a Phase 3 pivotal trial of AR-301 in VAP patientsin the second half of 2018, while AR-105 is currently in Phase 2 clinical testing, and AR-101 is ready for phase 2/3 pivotal testing. We are clinically testing AR-105 as a wellcontrolled Phase 2 trial; however, we have not yet had discussions with the FDA and the EMA regarding the status, and they may not agree. We cannot assure you that our planned clinicaldevelopment for our product candidates will be completed in a timely manner, or at all, or that we, or any future partner, will be able to obtain approval for our product candidates from the FDA orany foreign regulatory authority.

        Regulatoryagencies, including the FDA must approve our product candidates before they can be marketed or sold. The approval process is lengthy, requires significant capitalexpenditures, and is uncertain as to outcome. Our ability to obtain regulatory approval of any product candidate depends on, among other things, completion of additional clinical trials, whether ourclinical trials demonstrate statistically significant efficacy with safety issues that do not potentially outweigh the therapeutic benefit of the product candidates, and whether the regulatoryagencies agree that the data from our future clinical trials are sufficient to support approval for any of our product candidates. The final results of our current and future clinical trials may notmeet FDA or other regulatory agencies' requirements to approve a product candidate for marketing, and the regulatory agencies may otherwise determine that our manufacturing processes or facilities areinsufficient to support approval. We, and our current and potential future collaborators, may need to conduct more clinical trials than we currently anticipate. Even if we do receive FDA or otherregulatory agency approval, we or our collaborators may not be successful in commercializing approved product candidates. If any of these events occur, our business could be materially harmed and thevalue of our securities would decline.

We, or our collaborators, may face delays in completing our clinical trials, and may not be able to completethem at all.

        Clinical trials necessary to support an application for approval to market any of our product candidates have not been completed. Our, or ourcollaborators', current and future clinical trials

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maybe delayed, unsuccessful, or terminated as a result of many factors, including, but not limited to:

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delays in reaching agreement on trial design and clinical study protocol with investigators and regulatory authorities in various countrieswhere our clinical trials are being conducted;



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governmental or regulatory delays, failure to obtain regulatory approval or changes in regulatory requirements, policy or guidelines;



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adding new clinical trial sites;



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reaching agreement on acceptable terms with prospective contract research organizations, or CROs, and clinical trial sites, the terms of whichcan be subject to extensive negotiation and may vary significantly among different CROs and trial sites;



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the actual performance of CROs and clinical trial sites in ensuring the proper and timely conduct of our clinical trials;



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developing and validating companion diagnostics on a timely basis;



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adverse effects experienced by subjects in clinical trials;



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manufacturing sufficient quantities of product candidates for use in clinical trials;



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delay or failure in achieving study efficacy endpoints and completing data analysis for a trial;



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regulators or institutional review boards, or IRBs, may not authorize us to commence a clinical trial;



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regulators or IRBs may suspend or terminate clinical research for various reasons, including noncompliance with regulatory requirements orconcerns about patient safety;



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we may suspend or terminate our clinical trials if we believe that they expose the participating patients to unacceptable health risks;



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patients may not complete clinical trials due to safety issues, side effects, such as injection site discomfort, a belief that they arereceiving placebo instead of our product candidates, or other reasons;



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patients with serious diseases included in our clinical trials may die or suffer other adverse medical events for reasons that may not berelated to our product candidates;



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in those trials where our product candidate is being tested in combination with one or more other therapies, deaths may occur that may beattributable to the other therapies;



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we may have difficulty in maintaining contact with patients after treatment, preventing us from collecting the data required by our studyprotocol;



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product candidates may demonstrate a lack of efficacy during clinical trials;



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personnel conducting clinical trials may fail to properly administer our product candidates; and



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our collaborators may decide not to pursue further clinical trials.

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        Ifwe fail to raise the full amount of the net proceeds in this offering, the planned AR-301 Phase 3 pivotal trial may remain an 80% power study rather than 90% power study, whichwould reduce the probability that we reach statistical significance, and may negatively affect the approval process for AR-301. If the Cystic Fibrosis Foundation does not continue to providesufficient level of funding support, we may not be able to complete the Phase 1/2a clinical trial relating to AR-501.

        Inaddition, we rely on academic institutions, medical institutions, physician practices and CROs to conduct, supervise or monitor some or all aspects of clinical trials involving ourproduct candidates. We have less control over the timing and other aspects of these clinical trials than if we conducted the monitoring and supervision entirely on our own. Third parties may notperform their responsibilities for our clinical trials on our anticipated schedule or consistent with a clinical trial protocol or applicable regulations. We also may rely on CROs to perform our datamanagement and analysis. They may not provide these services as required or in a timely or compliant manner, and we may be held legally responsible for any or all of their performance failures orinadequacies.

        Ifwe or our collaborators experience delays in the completion of, or termination of, any clinical trial of our product candidates, the commercial prospects of our product candidateswill be harmed, and our ability to generate product revenues from any of these product candidates will be delayed or eliminated. In addition, any delays in completing our clinical trials will increaseour costs, slow our product candidate development and approval process, and jeopardize our ability to commence product sales and generate revenues. Any of these occurrences may harm our business,financial condition and prospects. In addition, many of the factors that cause, or lead to, a delayin the commencement or completion of clinical trials may also lead to the denial of regulatory approval of our product candidates.

If we encounter difficulties enrolling patients in our clinical trials, our clinical trials could be delayedor otherwise adversely affected.

        Clinical trials for our product candidates require us to identify and enroll a large number of patients with the disease under investigation. Wemay not be able to enroll a sufficient number of patients with required or desired characteristics to conduct our clinical trials in a timely manner, if at all. Patient enrollment is affected byfactors including, but not limited to:

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severity of the disease under investigation;



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design of the trial protocol;



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the size and nature of the patient population;



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eligibility criteria for the study in question;



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lack of a sufficient number of patients who meet the enrollment criteria for our clinical trials;



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delays in characterizing a patient's infection to allow us to select a product candidate, which may lead patients to seek to enroll in otherclinical trials or seek alternative treatments;



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perceived risks and benefits of the product candidate under study;



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availability of competing therapies and clinical trials;

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efforts to facilitate timely enrollment in clinical trials;



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scheduling conflicts with participating clinicians;



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patient referral practices of physicians;



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the ability to monitor patients adequately during and after treatment; and



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proximity and availability of clinical trial sites for prospective patients.

        Wehave experienced slower enrollment of patients in our smaller clinical trials due to the pace in which clinical sites were being initiated for enrollment and may experience similardifficulties in the future. In addition, AR-301 and AR-101 have been granted orphan drug designation for the treatment of P. aeruginosa and S. aureus inthe EU respectively, and the low prevalence of such diseases relative to the total population may make it harder to identify patients toenroll. If we have difficulty enrolling a sufficient number or diversity of patients to conduct our clinical trials as planned, we may need to delay or terminate ongoing or planned clinical trials,either of which would have an adverse effect on our business.

Our product candidates are based on a novel technology, which may raise development issues we may not be ableto resolve, regulatory issues that could delay or prevent approval, or personnel issues that may keep us from being able to develop our product candidates.

        Our product candidates are based on our mAb technology and gallium-based anti-infective platforms. There can be no assurance that developmentproblems related to our novel technologies will not arise in the future that will cause significant delays or that we will not able to resolve.

        Regulatoryapproval of novel product candidates such as ours can be more expensive and take longer than for other, more well-known or extensively studied pharmaceutical orbiopharmaceutical product candidates due to our and regulatory agencies' lack of experience withthem. Only two mAbs have been approved by the FDA. Synagis which stimulates the immune system to target a viral infection and ZINPLAVA to reduce recurrence of Clostridiumdifficile infections. The novelty of our platform may lengthen the regulatory review process, require us to conduct additional studies or clinical trials, increase ourdevelopment costs, lead to changes in regulatory positions and interpretations, delay or prevent approval and commercialization of our product candidates or lead to significant post-approvallimitations or restrictions. For example, the FDA could require additional studies that may be difficult or impossible to perform.

        Thenovel nature of our product candidates also means that fewer people are trained in or experienced with product candidates of this type, which may make it difficult to find, hire andretain capable personnel, particularly for research, development, commercialization and manufacturing positions. For example, study personnel may administer the wrong version of our product candidatesor assign study therapy to the wrong treatment group, resulting in potential disqualification of subjects from data analysis. These factors could potentially cause a trial to fail for a reasonunrelated to the efficacy of our product candidates. If we are unable to hire and retain the necessary personnel, the rate and success at which we can develop and commercialize product candidates willbe limited. Any such events would increase our costs and could delay or prevent our ability to commercialize our product candidates, which could adversely impact our business, financial condition andresults of operations.

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If we are unable to successfully develop companion diagnostics for our therapeutic product candidates, orexperience significant delays in doing so, we may not realize the full commercial potential of our product candidates.

        We intend to use rapid diagnostic tests of patients' respiratory samples to target our mAb product candidates to those patients we believe areinfected with the bacterial agents which our mAb will act against. However, currently there is no commercially available companion diagnostic for AR-101 and AR-401. Therefore, there is a risk that acompanion diagnostic for these products are not developed or available to support product launch. The FDA and similar regulatory authorities outside the United States regulate companion diagnostics.Companion diagnostics require separate or coordinated regulatory approval prior to commercialization of the therapeutic product. Changes to applicable regulations could delay our development programsor delay or prevent eventual marketing approval for our product candidates that may have otherwise been approved.

        TheFDA's evolving position on the topic of companion diagnostics could affect our clinical development programs that utilize companion diagnostics. In particular, the FDA may limit ourability to use retrospective data, otherwise disagree with our approaches to trial design, biomarker qualification, clinical and analytical validity, and clinical utility, or make us repeat aspects ofa trial or initiate new trials.

        Assaysthat can be used as companion diagnostics are commercially available, but in some cases such as for AR-101, they do not yet have regulatory approval for use as companiondiagnostic. We have limited experience in the development of diagnostics and may not be successful in developing necessary diagnostics to pair with those product candidates that require a companiondiagnostic.

        Givenour limited experience in developing diagnostics, we expect to rely in part on third parties for their design and manufacture. If we, or any third parties that we engage to assistus, are unable to successfully develop companion diagnostics for our product candidates that require such diagnostics, or experience delays in doing so, the development of our product candidates maybe adversely affected, our product candidates may not receive marketing approval and we may not realize the full commercial potential of any products that receive marketing approval. As a result, ourbusiness could be materially harmed.

Clinical development is a lengthy and expensive process with an uncertain outcome, and results of earlierstudies and clinical trials may not be predictive of future trial results.

        Clinical testing is expensive and can take many years to complete, and its outcome is inherently uncertain. Failure can occur at any time duringthe clinical trial process. The results of preclinical studies and early clinical trials of our product candidates may not be predictive of the design or results of later-stage clinical trials. Theresults regarding initial tolerability and clinical activity generated to date in clinical trials for our AR-301 and AR-101 product candidates in HAP and VAP patients do not ensure that later clinicaltrials will demonstrate similar results. While we have observed in exploratory analysis statistically significant improvements in the outcomes of some of our clinical trials, many of the improvementswe have seen have not reached statistical significance. Statistical significance is a statistical term that means that an effect is unlikely to have occurred by chance. In order to be approved by theFDA, European Medicines Agency, or EMA,

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orother drug approving authorities, product candidates must demonstrate that their effect on patients' diseases in the trial is statistically significant and clinically meaningful. Product candidatesin later stages of clinical trials may fail to show the desired safety and efficacy traits despite having progressed through preclinical studies and initial clinical trials. Early clinical trialsfrequently enroll patient populations that are different from the patient populations in later trials, resulting in different outcomes in later clinical trials from those in earlier stage clinicaltrials. In addition, adverse events may not occur in early clinical trials and only emerge in larger, late-stage clinical trials or after commercialization. Companies in the biopharmaceutical industryhave suffered significant setbacks in advanced clinical trials due to lack of efficacy or adverse safety profiles, notwithstanding promising results in earlier clinical trials. If later stage clinicaltrials do not demonstrate efficacy and safety of our product candidates we will not be able to market them and our business will be materially harmed.

We may seek a breakthrough therapy designation for our existing and future product candidates, but we mightnot receive such designation, and even if we do, such designation may not lead to a faster development or regulatory review or approval process.

        We may seek a breakthrough therapy designation for our existing and future product candidates; however, we cannot assure you our productcandidates will meet the criteria for that designation. A breakthrough therapy is defined as a therapy that is intended, alone or in combination with one or more other therapies, to treat a seriouscondition, and preliminary clinical evidence indicates that the therapy may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such assubstantial treatment effects observed early in clinical development. For therapies and biologics that have been designated as breakthrough therapies, interaction and communication between the FDA andthe sponsor of the trial can help to identify the most efficient path for clinical development while minimizing the number of patients placed in ineffective control regimens. Therapies designated asbreakthrough therapies by the FDA may also be eligible for priority review if supported by clinical data at the time the new drug application is submitted to the FDA.

        Designationas a breakthrough therapy is within the discretion of the FDA. Accordingly, even if we believe that one of our product candidates meets the criteria for designation as abreakthrough therapy, the FDA may disagree and instead determine not to make such designation. Even if we receive breakthrough therapy designation, the receipt of such designation for a productcandidate may not result in a faster development or regulatory review or approval process compared to drugs considered for approval under conventional FDA procedures and does not assure ultimateapproval by the FDA. In addition, even if one or more of our product candidates qualify as breakthrough therapies, the FDA may later decide that the product candidate no longer meets the conditionsfor qualification or decide that the time period for FDA review or approval will not be shortened.

Designation of our product candidates as qualified infectious disease products is not assured and, in anyevent, even if granted, may not actually lead to a faster development or regulatory review, and would not assure FDA approval of our product candidates.

        We may seek designation of our existing and future product candidates as qualified infectious disease products, or QIDP. A QIDP is anantibacterial or antifungal drug intended to treat serious

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orlife- threatening infections, including those caused by an antibacterial or antifungal resistant pathogen, including novel or emerging infectious pathogens or certain "qualifying pathogens." Aproduct designated as a QIDP for a particular indication will also be granted priority review by the FDA and can qualify for fast track status. Upon the approval of an NDA for a drug productdesignated by the FDA as a QIDP, the product is granted a period of five years of regulatory exclusivity that is in addition to any other period of regulatory exclusivity for which the product iseligible. The FDA has broad discretion whether or not to grant these designations, so even if we believe a particular product candidate is eligible for such designation or status, the FDA could decidenot to grant it. Moreover, even if we do receive such a designation, we may not experience a faster development process, review or approval compared to conventional FDA procedures and there is noassurance that our product candidate, even if determined to be a QIDP, will be approved by the FDA.

Regulatory authorities may not approve our product candidates even if they meet safety and efficacy endpointsin clinical trials.

        The time required to obtain approval by the FDA and comparable foreign authorities is unpredictable but typically takes many years following thecommencement of clinical trials and depends upon numerous factors, including the substantial discretion of regulatory authorities. In addition, approval policies, regulations, or the type and amountof clinical data necessary to gain approval may change during the course of a product candidate's clinical development and may vary among jurisdictions. We have discussions with and obtain guidancefrom regulatory authorities regarding certain aspects of our clinical development activities. These discussions are not binding commitments on the part of regulatory authorities. Under certaincircumstances, regulatory authorities may revise or retract previous guidance during the course of our clinical activities or after the completion of our clinical trials. A regulatory authority mayalso disqualify a clinical trial in whole or in part from consideration in support of approval of a potential product for commercial sale or otherwise deny approval of that product. Prior toregulatory approval, a regulatory authority may elect to obtain advice from outside experts regarding scientific issues and/or marketing applications under a regulatory authority review. In the UnitedStates, these outside experts are convened through the FDA's Advisory Committee process, which would report to the FDA and make recommendations that may differ from the views of the FDA. Should anAdvisory Committee be convened, it would be expected to lengthen the time for obtaining regulatory approval, if such approval is obtained at all.

        TheFDA and foreign regulatory agencies may delay, limit or deny marketing approval for many reasons, including, but not limited to:

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a product candidate may not be considered safe or effective;



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our manufacturing processes or facilities may not meet the applicable requirements;



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changes in the agencies' approval policies or adoption of new regulations may require additional work on our part, for example, the FDA mayrequire us to change or expand the endpoints in our clinical trials;



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different divisions of the FDA are reviewing different product candidates and those divisions may have different requirements for approval; and

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changes in regulatory law, FDA or foreign regulatory agency organization, or personnel may result in different requirements for approval thananticipated.

        Ourproduct candidates may not be approved even if they achieve their endpoints in clinical trials. Regulatory agencies, including the FDA, or their advisors may disagree with our trialdesign and our interpretations of data from preclinical studies and clinical trials. Regulatory agencies also may approve a product candidate for fewer or more limited indications than requested ormay grant approval subject to the performance of post-marketing studies. In addition, regulatory agencies may not approve the labeling claims that are necessary or desirable for the successfulcommercialization of our product candidates. We have not obtained regulatory approval for any product candidate, and it is possible that none of our existing product candidates or any productcandidates we may seek to develop in the future will ever obtain regulatory approval.

        Anydelay in or failure to receive or maintain approval for any of our product candidates could prevent us from ever generating revenues or achieving profitability.

We may be required to suspend, repeat or terminate our clinical trials if they are not conducted inaccordance with regulatory requirements, the results are negative or inconclusive, or the trials are not well designed.

        Clinical trials must be conducted in accordance with FDA regulations governing clinical studies, or other applicable foreign governmentguidelines, and are subject to oversight by the FDA, other foreign governmental agencies and IRBs/Ethic Committees at the medical institutions where the clinical trials are conducted. In addition,clinical trials must be conducted with product candidates produced under current Good Manufacturing Practices, or cGMP, and may require large numbers of test subjects. Clinical trials may be suspendedby the FDA, other foreign governmental agencies or us for various reasons, including, but not limited to:

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deficiencies in the conduct of the clinical trials, including failure to conduct the clinical trial in accordance with regulatory requirementsor clinical protocols;



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deficiencies in the clinical trial operations or trial sites;



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the product candidate may have unforeseen adverse side effects;



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the time required to determine whether the product candidate is effective may be longer than expected;



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deaths or other adverse events arising during a clinical trial due to medical problems that may not be related to clinical trial treatments;



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the product candidate may not appear to be more effective than current therapies;



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the quality or stability of the product candidate may fall below acceptable standards; and



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insufficient quantities of the product candidate might be available to complete the trials.

        Inaddition, changes in regulatory requirements and guidance may occur and we may need to amend clinical trial protocols to reflect these changes. Amendments may require us to resubmitour clinical trial protocols to IRBs for reexamination, which may impact the costs, timing or successful completion of a clinical trial. Due to these and other factors, our product candidates couldtake longer to gain regulatory approval than we expect or we may never gain approval for

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anyproduct candidates, which could reduce or eliminate our revenue by delaying or terminating the commercialization of our product candidates.

A Fast Track product designation or other designation to facilitate product candidate development may notlead to faster development or regulatory review or approval process, and it does not increase the likelihood that our product candidates will receive marketing approval.

        We have received a Fast Track product designation for AR-301 and AR-101 and we may seek Fast Track designation for other of our current orfuture product candidates. Receipt of a designation to facilitate product candidate development is within the discretion of the FDA. Accordingly, even if we believe one of our product candidates meetsthe criteria for a designation, the FDA may disagree. In any event, the receipt of such a designation for a product candidate may not result in a faster development process, review, or approvalcompared to drugs considered for approval under conventional FDA procedures and does not assure ultimate marketing approval by the FDA. In addition, the FDA may later decide that the products nolonger meet the designation conditions.

We may not be able to maintain orphan drug marketing exclusivity for our AR-101 and AR-301 product candidatesin the United States and/or the European Union, and orphan drug marketing exclusivity may not be available for any of our other product candidates.

        Under the Orphan Drug Act, the FDA may grant orphan drug designation to a drug or biologic intended to treat a rare disease or condition (with apopulation of less than 200,000), which is defined as one occurring in a patient population of fewer than 200,000 in the United States, or a patient population greater than 200,000 in the U.S. wherethere is no reasonable expectation that the cost of developing the drug or biologic will be recovered from sales in the United States. In the EU, following the opinion of the EMA's Committee forOrphan Medicinal Products, the European Commission grants orphan drug designation to a product if (1) it is intended for the diagnosis, prevention or treatment of a life-threatening orchronically debilitating condition; (2) either (a) such condition affects no more than five in 10,000 persons in the EU when the application is made, or (b) the product, withoutthe incentives derived from orphan medicinal product status, would not generate sufficient return in the EU to justify investment; and (3) there exists no satisfactory method of diagnosis,prevention or treatment of such condition authorized for marketing in the EU, or if such a method exists, the product will be of significant benefit to those affected by the condition.

        Generally,if a drug with an orphan drug designation subsequently receives the first marketing approval for the indication for which it has such designation, the drug is entitled to aperiod of marketing exclusivity, which precludes the FDA or the European Commission and the competent authorities in the EU Member States from approving another marketing application for the samedrug (or similar medicinal product in the European Union) for that time period, except in limited circumstances. The applicable period is seven years in the U.S. and 10 years in the EU. The EUexclusivity period can be reduced to six years if a drug no longer meets the criteria for orphan drug designation or if the drug is sufficiently profitable that market exclusivity is no longerjustified. Orphan drug exclusivity may be lost if the FDA determines that the request for designation was materially defective or if the manufacturer is unable to assure sufficient quantity of thedrug to meet the needs of patients with the rare disease or condition.

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        Wehave been granted orphan drug designation for our AR-101 and AR-301 drug candidates in the European Union, as well as orphan drug designation for our AR-101 drug candidate in the U.S.Although we may apply for orphan drug designation for other product candidates we may develop in both the U.S. and EU, applicable regulatory authorities may not grant us this designation. In addition,even if such status is obtained for any other product candidate that we may develop, that exclusivity may not effectively protect the candidate from competition because other drugs, such as those withdifferent active ingredients or molecular structures, can be approved for the same condition. Furthermore, even after an orphan drug is approved, the FDA can subsequently approve another drug for thesame condition if the FDA concludes that the later drug is clinically superior, in that it is shown to be safer, more effective or makes a major contribution to patient care. In the EU, a marketingauthorization may be granted to a similar product during the 10-year period of market exclusivity for the same therapeutic indication at any time if:

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The second applicant can establish in its application that its product, although similar to the orphan medicinal product already authorized, issafer, more effective or otherwise clinically superior;



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The holder of the marketing authorization for the original orphan medicinal product consents to a second orphan medicinal product application;or



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The holder of the marketing authorization for the original orphan medicinal product cannot supply enough orphan medicinal product.

        Anyinability to secure orphan drug designation or to maintain the exclusivity benefits of this designation could have an adverse impact on our ability to develop and commercialize ourproduct candidates, depending on the extent to which we would be protected by other patents and regulatory exclusivities, and may adversely affect our business, prospects, financial condition andresults of operations.

Any product candidate for which we, or our collaborators, obtain marketing approval could be subject torestrictions or withdrawal from the market, and we may be subject to penalties if we fail to comply with regulatory requirements or if we experience unanticipated problems with our products, when andif any of them are approved.

        Any product candidate that we, or our collaborators, obtain marketing approval for, along with the manufacturing processes, post-approvalclinical data, labeling, advertising and promotional activities for such product, will be subject to continuing requirements of the FDA and other regulatory authorities. These requirements includesubmissions of safety and other post-marketing information, reports, facility registration and product listing requirements, cGMP requirements relating to quality control, quality assurance andcorresponding maintenance of records and documents, requirements regarding the distribution of samples to physicians and recordkeeping. Even if marketing approval of a product candidate is granted,the approval may be subject to limitations on the indicated uses for which the product may be marketed or to conditions of approval, or contain requirements for costly post-marketing testing andsurveillance to monitor the safety or efficacy of the product. The FDA closely regulates the post-approval marketing and promotion of drugs to ensure drugs are marketed only for the approvedindications and in accordance with the provisions of the approved labeling. The FDA imposes stringent restrictions

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onmanufacturers' communications regarding off-label use. If we market our products outside of their approved indications, we will be subject to enforcement action for off-label marketing.

        Inaddition, later discovery of previously unknown problems with these products, manufacturers or manufacturing processes, or failure to comply with regulatory requirements, may yieldvarious results, including, but not limited to:

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restrictions on such products, manufacturers or manufacturing processes;



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restrictions on the labeling or marketing of a product;



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restrictions on product distribution or use;



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requirements to conduct post-marketing clinical trials;



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warning or untitled letters;



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withdrawal of the products from the market;



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refusal to approve pending applications or supplements to approved applications that we submit;



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recall of products, fines, restitution or disgorgement of profits or revenue;



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suspension or withdrawal of marketing approvals;



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refusal to permit the import or export of our products;



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product seizure; and



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injunctions or the imposition of civil or criminal penalties.

        TheFDA's policies may change and additional government regulations may be enacted that could prevent, limit or delay regulatory approval of our product candidates. If we, or ourcollaborators,are slow or unable to adapt to changes in existing requirements or the adoption of new requirements or policies, or if we, or our collaborators, are not able to maintain regulatory compliance, anymarketing approval that was obtained could be lost, which would adversely affect our business, prospects and ability to achieve or sustain profitability.

If we, or our collaborators, are unable to comply with foreign regulatory requirements or obtain foreignregulatory approvals, our ability to develop foreign markets for our products could be impaired.

        Sales of our products outside the U.S. will be subject to foreign regulatory requirements governing clinical trials, marketing approval,manufacturing, product licensing, pricing and reimbursement. These regulatory requirements vary greatly from country to country. As a result, the time required to obtain approvals outside the U.S. maydiffer from that required to obtain FDA approval and we may not be able to obtain foreign regulatory approvals on a timely basis or at all. Approval by the FDA does not ensure approval by regulatoryauthorities in other countries, and approval by one foreign regulatory authority does not ensure approval by regulatory authorities in other countries or by the FDA and foreign regulatory authoritiescould require additional testing. Failure to comply with these regulatory requirements or obtain required approvals could impair our ability to develop foreign markets for our products.

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We are subject to U.S. and certain foreign export and import controls, sanctions, embargoes, anti-corruptionlaws, and anti-money laundering laws and regulations. Compliance with these legal standards could impair our ability to compete in domestic and international markets. We can face criminal liabilityand other serious consequences for violations, which can harm our business.

        We are subject to export control and import laws and regulations, including the U.S. Export Administration Regulations, U.S. Customsregulations, various economic and trade sanctions regulations administered by the U.S. Treasury Department's Office of Foreign Assets Controls, the U.S. Foreign Corrupt Practices Act of 1977, asamended, or FCPA, the U.S. domestic bribery statute contained in 18 U.S.C. § 201, the U.S. Travel Act, the USA PATRIOT Act, and other state and national anti-bribery and anti-moneylaundering laws in thecountries in which we conduct activities. Anti-corruption laws are interpreted broadly and prohibit companies and their employees, agents, contractors, and other collaborators from authorizing,promising, offering, or providing, directly or indirectly, improper payments or anything else of value to recipients in the public or private sector. We may engage third parties for clinical trialsoutside of the United States, to sell our products abroad once we enter a commercialization phase, and/or to obtain necessary permits, licenses, patent registrations, and other regulatory approvals.We have direct or indirect interactions with officials and employees of government agencies or government-affiliated hospitals, universities, and other organizations. We can be held liable for thecorrupt or other illegal activities of our employees, agents, contractors, and other collaborators, even if we do not explicitly authorize or have actual knowledge of such activities. Any violationsof the laws and regulations described above may result in substantial civil and criminal fines and penalties, imprisonment, the loss of export or import privileges, debarment, tax reassessments,breach of contract and fraud litigation, reputational harm, and other consequences.

Developing product candidates in combination with other therapies may lead to unforeseen side effects orfailures in our clinical trials.

        We, and our collaborators, are studying our product candidates in clinical trials in combination with approved therapies, including antibiotics,and we anticipate that if any product candidates are approved for marketing, they will be approved to be used only in combination with other therapies. Our development programs and planned studiescarry all the risks inherent in drug development activities, including the risk that they will fail to demonstrate meaningful efficacy or acceptable safety. In addition, our development programs aresubject to additional regulatory, commercial, manufacturing and other risks because of the use of other therapies in combination with our product candidates. For example, the other therapies may leadto toxicities that are improperly attributed to our product candidates or the combination of our product candidates with other therapies may result in toxicities that the product candidate or othertherapy does not produce when used alone. The other therapies we are using in combination with our product candidates may be removed from the market or become prohibitively expensive and thus beunavailable for testing or commercial use with any of our approved products. Testing product candidates in combination with other therapies may increase the risk of significant adverse effects or testfailures. The timing, outcome and cost of developing products to be used in combination with other therapies is difficult to predict and dependent on a number of factors that are outside ourreasonable control. If any safety or toxicity issues arise in these clinical trials or with any approved products, or if the other therapies are removed from the market, the products may not beapproved, which could prevent us from ever generating revenues or achieving profitability.

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We will need to develop or acquire additional manufacturing and distribution capabilities, or outsource thesame to third parties, in order to commercialize any product candidates that obtain marketing approval, and we may encounter unexpected costs or difficulties in doing so.

        If we independently develop and commercialize one or more of our product candidates, we will need to invest in acquiring or building additionalcapabilities and effectively manage our operations and facilities to successfully pursue and complete future research, development and commercialization efforts. We will require additional investmentand validation process development in order to qualify our commercial-scale manufacturing process to manufacture clinical trial materials and commercial material if any of our products are approvedfor marketing. This investment and validation process development may be expensive and time-consuming. We will require additional personnel with experience in commercial-scale manufacturing, managingof large-scale information technology systems and managing a large-scale distribution system. We will need to add personnel and expand our capabilities, which may strain our existing managerial,operational, regulatory compliance, financial and other resources. To do this effectively, we must:

•

recruit, hire, train, manage and motivate a growing employee base;



•

accurately forecast demand for our products;



•

assemble and manage the supply chain to ensure our ability to meet demand; and



•

expand existing operational, manufacturing, financial and management information systems.

        Wemay seek FDA approval for our production process and facilities simultaneously with seeking approval for sale of our product candidates. Should we not complete the development ofadequate manufacturing and distribution capabilities, including manufacturing capacity, or fail to receive timely approval of our manufacturing process and facilities, our ability to supply clinicaltrial materials for planned clinical trials or supply products following regulatory approval for sale could be delayed, which would further delay our clinical trials or the period of time when wewould be able to generate revenues from the sale of such products, if we are even able to obtain approval or generate revenues at all.

        Additionally,we may decide to outsource some or all of our manufacturing activities to a third party commercial manufacturing organization, or CMO. Under any agreement with a CMO, wewould have less control over the timing and quality of manufacturing than if we were to perform such manufacturing ourselves. A CMO would be manufacturing other pharmaceutical products in the samefacilities as our product candidates, increasing the risk of cross product contamination. Further, there is no guarantee that any CMO will continue ongoing operations, causing potential delays inproduct supply, reduced revenues and other liabilities for us.

        Anysuch events would increase our costs and could delay or prevent our ability to commercialize our product candidates, which could adversely impact our business, financial conditionand results of operations.

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Our product candidates may cause undesirable side effects or have other properties that could delay orprevent their regulatory approval, limit the commercial profile of an approved label, or result in significant negative consequences following marketing approval, if any.

        Undesirable side effects caused by our product candidates could cause us, our collaborators, or regulatory authorities to interrupt, delay orhalt clinical trials and could result in a more restrictive label, the delay or denial of regulatory approval by the FDA or other comparable foreign regulatory authorities, or litigation by injuredpatients, if any. To date, patients treated with AR-301 and AR-101 have experienced AEs related to the study drug, some of which have been serious. Regarding AR-301, few (2.8%) adverse events, or AEs,were deemed related, and no serious adverse events, or SAEs, were deemed to be related to AR-301 treatment. There were six deaths in the trial, none of which were deemed related to AR-301. RegardingAR-101, 12 SAEs were experienced by five subjects. An event of cardiorespiratory arrest was judged as probably related to AR-101 and events of hyperbilirubinemia and cholestasis, althoughpre-existent, were deemed possibly related. In both cases, the causality assessment by the investigators accounted for the fact that a contribution by AR-101 to the AE could not be excluded withcertainty although other probable causes were acknowledged. The other SAEs were deemed unrelated.

        Becauseour product candidates are intended to assist the immune system, our clinical trials could reveal an unacceptable severity and prevalence of side effects, including, but notlimited to, adverse immune responses that lead to previously unobserved complications. As a result of any side effects, our clinical trials could be suspended or terminated and the FDA or comparableforeign regulatory authorities could order us to cease further development, or deny approval, of our product candidates for any or all targeted indications. The drug-related side effects could affectpatient recruitment or the ability of enrolled patients to complete the trial or result in potential product liability claims. Any of these occurrences may harm our business, financial condition andprospects significantly.

        Additionally,if one or more of our product candidates receives marketing approval, and we, our collaborators, or others later identify undesirable side effects caused by such products,a number of potentially significant negative consequences could result, including, but not limited to:

•

regulatory authorities may withdraw approvals of such product;



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regulatory authorities may require additional warnings on the label;



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we may be required to create a medication guide outlining the risks of such side effects for distribution to patients;



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we may be sued and held liable for harm caused to patients; and



•

our reputation may suffer.

        Inaddition, we cannot assure you that the bacteria which our mAbs target will not in the future develop a resistance to our mAbs.

        Anyof these events could prevent us from achieving or maintaining market acceptance of the particular product candidate, if approved, and could significantly harm our business, resultsof operations and prospects.

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If we cannot conduct the non-clinical testing required by regulatory authorities to demonstrate an acceptabletoxicity profile for our product candidates in non-clinical studies, we will not be able to initiate or continue clinical trials or obtain approval for our product candidates.

        In order to move a product candidate into human clinical trials, we must first demonstrate an acceptable toxicity profile in preclinicaltesting. Furthermore, in order to obtain approval, we must also demonstrate safety in various non-clinical tests. We may not have conducted or may not conduct the types of non-clinical testingrequired by regulatory authorities, or future non-clinical tests may indicate that our product candidates are not safe for use. Preclinical and non-clinical testing is expensive, time-consuming andhas an uncertain outcome. In addition, success in initial non-clinical testing does not ensure that later non-clinical testing will be successful. We may experience numerous unforeseen events during,or as a result of, the non-clinical testing process, which could delay or prevent our ability to develop or commercialize our product candidates, including, but not limitedto:

•

our preclinical and non-clinical testing may produce inconclusive or negative safety results, which may require us to conduct additionalnon-clinical testing or to abandon product candidates;



•

our product candidates may have unfavorable pharmacology or toxicity characteristics;



•

our product candidates may cause undesirable side effects such as negative immune responses that lead to complications;



•

our enrolled patients may have allergies that lead to complications after treatment; and



•

the FDA or other regulatory authorities may determine that additional safety testing is required.

        Anysuch events would increase our costs and could delay or prevent our ability to commercialize our product candidates, which could adversely impact our business, financial conditionand results of operations.

Because we have multiple product candidates in our clinical pipeline and are considering a variety of targetindications, we may expend our limited resources to pursue a particular product candidate or indication and fail to capitalize on product candidates or indications that may be more profitable or forwhich there is a greater likelihood of success.

        Because we have limited financial and managerial resources, we must focus our research and development efforts on those product candidates andspecific indications that we believe are the most promising. As a result, we may forego or delay our pursuit of opportunities with other product candidates or other indications that later prove tohave greater commercial potential. Our resource allocation decisions may cause us to fail to capitalize on viable commercial products or profitable market opportunities. We may in the future spend ourresources on other research programs and product candidates for specific indications that ultimately do not yield any commercially viable products. Furthermore, if we do not accurately evaluate thecommercial potential or target market for a particular product candidate, we may relinquish valuable rights to that product candidate through collaboration, licensing or other royalty arrangements incases in which it would have been more advantageous for us to retain sole development and commercialization rights.

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If we are unable to establish sales and marketing capabilities or enter into agreements with third parties tosell and market our product candidates, we may not be successful in commercializing our product candidates if and when they are approved.

        We do not have a sales and marketing infrastructure or any experience in the sales, marketing or distribution of pharmaceutical products. We mayseek additional third-party collaborators for the commercialization of our other product candidates. In the future, we may choose to build a focused sales and marketing infrastructure to market orco-promote some of our product candidates if and when they are approved, which would be expensive and time-consuming. Alternatively, we may elect to outsource these functions to third parties. Eitherapproach carries significant risks. For example, recruiting and training a sales force is expensive and time-consuming and, if done improperly, could delay a product launch and result in limitedsales. If the commercial launch of a product candidate for which we recruit a sales force and establish marketing capabilities is delayed or does not occur for any reason, we would have prematurely orunnecessarily incurred these commercialization expenses. This may be costly, and our investment would be lost if we cannot retain or reposition our sales and marketing personnel. Outsourcing sales andmarketing capabilities will depend on our ability to enter into and maintain agreements with other companies having sales, marketing and distribution capabilities, the ability of such companies tosuccessfully market and sell our product candidates, and our ability to enter into such agreements on terms favorable to us.

        Factorsthat may inhibit our efforts to commercialize our products on our own include, but are not limited to:

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our inability to recruit, manage and retain adequate numbers of effective sales and marketing personnel;



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the inability of marketing personnel to develop effective marketing materials;



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the inability of sales personnel to obtain access to or persuade adequate numbers of physicians to prescribe any future products;



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the lack of complementary products to be offered by sales personnel, which may put us at a competitive disadvantage relative to companies withmore extensive product lines; and



•

unforeseen costs and expenses associated with creating an independent sales and marketing organization.

        Entryinto agreements with third parties to sell and market our product candidates will subject us to a number of risks, including, but not limited to, thefollowing:

•

we may be required to relinquish important rights to our products or product candidates;



•

we may not be able to control the amount and timing of resources that our distributors or collaborators may devote to the commercialization ofour product candidates;



•

distributors or collaborators may experience financial difficulties;



•

our distributors or collaborators may not devote sufficient time to the marketing and sales of our products; and

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•

business combinations or significant changes in a collaborator's business strategy may adversely affect a collaborator's willingness or abilityto complete its obligations under any arrangement.

The availability and amount of reimbursement for our product candidates, if approved, and the manner in whichgovernment and private payors may reimburse for any potential products, are uncertain.

        Obtaining coverage and reimbursement approval for a product from a government or other third-party payor is a time-consuming and costly processthat could require us to provide supporting scientific, clinical and cost effectiveness data for the use of our products to the payor. There may be significant delays in obtaining such coverage andreimbursement for newly approved products, and coverage may be more limited than the purposes for which the product is approved by the FDA or similar regulatory authorities outside of the UnitedStates. Moreover, eligibility for coverage and reimbursement does not imply that a product will be paid for in all cases or at a rate that covers our costs, including research, development,intellectual property, manufacture, sale and distribution expenses. Reimbursement rates may vary according to the use of the product and the clinical setting in which it is used, may be based onreimbursement levels already set for lower cost products and may be incorporated into existing payments for other services. Net prices for products may be reduced by mandatory discounts or rebatesrequired by government healthcare programs or private payors and by any future relaxation of laws that presently restrict imports of product from countries where they may be sold at lower prices thanin the United States.

        Thereis significant uncertainty related to the insurance coverage and reimbursement of newly approved products. Third-party payors often rely upon Medicare coverage policy and paymentlimitations in setting their own reimbursement policies, but also have their own methods and approval process apart from Medicare coverage and reimbursement determinations. It is difficult to predictat this time what third party payors will decide with respect to the coverage and reimbursement for our product candidates. Our inability to promptly obtain coverage and adequate reimbursement ratesfrom both government-funded and private payors for any approved products that we develop could have a material adverse effect on our operating results, our ability to raise capital needed tocommercialize products and our overall financial condition.

        Reimbursementmay impact the demand for, and/or the price of, any product for which we obtain marketing approval. Assuming we obtain coverage for a given product by a third-party payor,the resulting reimbursement payment rates may not be adequate or may require co-payments that patients find unacceptably high. Patients who are prescribed medications for the treatment of theirconditions, and their prescribing physicians, generally rely on third-party payors to reimburse all or part of the costs associated with those medications. Patients are unlikely to use our productsunless coverage is provided and reimbursement is adequate to cover all or a significant portion of the cost of our products. Therefore, coverage and adequate reimbursement is critical to new productacceptance. Coverage decisions may depend upon clinical and economic standards that disfavor new drug products when more established or lower cost therapeutic alternatives are already available orsubsequently become available.

        TheU.S. government, state legislatures and foreign governmental entities have shown significant interest in implementing cost containment programs to limit the growth of government-paidhealthcare costs, including price controls, restrictions on reimbursement and coverage and requirements for substitution of generic products for branded prescription drugs.

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Adoptionof government controls and measures, and tightening of restrictive policies in jurisdictions with existing controls and measures, could exclude or limit our products from coverage and limitpayments for pharmaceuticals.

        Inaddition, we expect that the increased emphasis on managed care and cost containment measures in the U.S. by third-party payors and government authorities to continue and will placepressure on pharmaceutical pricing and coverage. Coverage policies and third-party reimbursement rates may change at any time. Even if favorable coverage and reimbursement status is attained for oneor more drug products for which we receive regulatory approval, less favorable coverage policies and reimbursement rates may be implemented in the future.

Failure to attract and retain key personnel could impede our ability to develop our products and to obtainnew collaborations or other sources of funding.

        Because of the specialized scientific nature of our business and the unique properties of our antibody platform, our success is highly dependentupon our ability to attract and retain qualified scientific and technical personnel, consultants and advisors. We depend greatly on our founders Dr. Vu Truong, our Chief Executive Officer,Chief Scientific Officer and a Director, and Dr. Eric Patzer, our Executive Chairman. We will also need to recruit a significant number of additional personnel in order to achieve our operatinggoals and financial reporting obligations. In order to pursue our product development and marketing and sales plans, we will need to hire additional qualified scientific personnel to perform researchand development, as well as personnel with expertise in clinical testing, government regulation, manufacturing, marketing and sales, which may strain our existing managerial, operational, regulatorycompliance, financial and other resources. We also rely on consultants and advisors to assist in formulating our research and development strategy and adhering to complex regulatory requirements. Weface competition for qualified individuals from numerous pharmaceutical and biotechnology companies, universities and other research institutions. There can be no assurance that we will be able toattract and retain such individuals on acceptable terms, if at all. The failure to attract and retain qualified personnel, consultants and advisors could have a material adverse effect on ourbusiness, financial condition and results of operations.

We may expend our limited resources to pursue a particular product candidate or indication and fail tocapitalize on product candidates or indications that may be more profitable or for which there is a greater likelihood of success.

        Because we have limited financial and managerial resources, we focus on research programs and product candidates for the indications that webelieve are the most scientifically and commercially promising. Our resource allocation decisions may cause us to fail to capitalize on viable scientific or commercial products or profitable marketopportunities. In addition, we may spend valuable time and managerial and financial resources on research programs and product candidates for specific indications that ultimately do not yield anyscientifically or commercially viable products. If we do not accurately evaluate the scientific and commercial potential or target market for a particular product candidate, we may relinquish valuablerights to that product candidate through collaboration, licensing or other royalty arrangements in situations where it would have been more advantageous for us to retain sole rights to development andcommercialization.

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Risks Relating to Our Financial Position and Need for Additional Capital

We expect to continue to incur increasing net losses for the foreseeable future, and we may never achieve ormaintain profitability.

        We are a clinical-stage biopharmaceutical company with a limited operating history. Investment in biopharmaceutical product development ishighly speculative because it entails substantial upfront capital expenditures and significant risk that any potential product candidate will fail to demonstrate adequate effect or an acceptablesafety profile, gain regulatory approval and become commercially viable. We have no products approved for commercial sale and have not generated any revenue from product sales to date, and we continueto incur significant research and development and other expenses related to our ongoing operations. As a result, we are not profitable and have incurred losses in each period since our inception. Forthe year ended December 31, 2017, we reported a net loss of approximately $27.5 million. For the three months ended March 31, 2018, we reported a net loss of approximately $8.2 million.As of March 31, 2018, we had an accumulated deficit of $55.8 million.

        Tobecome and remain profitable, we or our partners must succeed in developing our product candidates, obtaining regulatory approval for them, and manufacturing, marketing and sellingthose products for which we or our partners may obtain regulatory approval. We or they may not succeed in these activities, and we may never generate revenue from product sales that is significantenough to achieve profitability. Because of the numerous risks and uncertainties associated with biopharmaceutical product development and commercialization, we are unable to accurately predict thetiming or amount of future expenses or when, or if, we will be able to achieve or maintain profitability. Currently, we have no products approved for commercial sale, and to date we have not generatedany product revenue. We have financed our operations primarily through the sale of equity securities, upfront payments pursuant to collaborationagreements, government grants and capital lease and equipment financing. The size of our future net losses will depend, in part, on the rate of growth or contraction of our expenses and the level andrate of growth, if any, of our revenues. Our ability to achieve profitability is dependent on our ability, alone or with others, to complete the development of our products successfully, obtain therequired regulatory approvals, manufacture and market our proposed products successfully or have such products manufactured and marketed by others, and gain market acceptance for such products. Therecan be no assurance as to whether or when we will achieve profitability.

Available cash resources may be insufficient to provide for our working capital needs for the next twelvemonths. In the event such cash resources are insufficient to provide for our working capital requirements, we will need to raise additional capital to continue as a going concern.

        Our recurring losses from operations raise substantial doubt about our ability to continue as a going concern. The accompanying consolidatedinterim financial statements have been prepared on a going concern basis that contemplates the realization of assets and discharge of liabilities in their normal course of business. We have sufferedrecurring losses from operations since inception and negative cash flows from operating activities during the three months ended March 31, 2018 and years ended December 31, 2017 and2016. We expect to incur additional operating losses in the foreseeable future as we continue our product development programs. Our ability to continue as a going concern will require us to obtainadditional funding. We believe that the net proceeds from this offering, together with our existing cash and cash equivalents and, will allow us to fund

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ouroperating plan through at least the next twelve months. We have based these estimates, however, on assumptions that may prove to be wrong, and we could spend our available financialresources much faster than we currently expect and need to raise additional funds sooner than we anticipate. If we are unable to raise capital when needed or on acceptable terms, we would be forced todelay, reduce or eliminate our research and development programs and commercialization efforts.

We will require substantial additional capital in the future. If additional capital is not available, we willhave to delay, reduce or cease operations.

        Developing pharmaceutical products, including conducting preclinical studies and clinical trials, is expensive. Development of our productcandidates will require substantial additional funds to conduct research, development and clinical trials necessary to bring such product candidates to market and to establish manufacturing, marketingand distribution capabilities. We expect our development expenses to substantially increase in connection with our ongoing activities, particularly as we advance our clinical programs. Our futurecapital requirements will depend on many factors, including, among others:

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the scope, rate of progress, results and costs of our preclinical and non-clinical studies, clinical trials and other research and developmentactivities;



•

the scope, rate of progress and costs of our manufacturing development and commercial manufacturing activities;



•

the cost, timing and outcomes of regulatory proceedings, including FDA review of any Biologics License Application, or BLA, or New DrugApplication, or NDA, that we file;



•

payments required with respect to development milestones we achieve under our in-licensing agreements, including any such payments toUniversity of Chicago, University of Iowa, Brigham and Women's Hospital, Inc., Brigham Young University, Public Health Service and Kenta Biotech Ltd.;



•

the costs involved in preparing, filing, prosecuting, maintaining and enforcing patent claims;



•

the costs associated with commercializing our product candidates, if they receive regulatory approval;



•

the cost and timing of establishing sales and marketing capabilities;



•

competing technological efforts and market developments;



•

changes in our existing research relationships;



•

our ability to establish collaborative arrangements to the extent necessary;



•

revenues received from any future products;



•

the ability to achieve and receive milestone payments for products licensed to collaborators; and



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payments received under any future strategic collaborations.

        Weanticipate that we will continue to generate significant losses for the next several years as we incur expenses to complete our clinical trial programs for our product candidates,build

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commercialcapabilities, develop our pipeline and expand our corporate infrastructure. We believe that the net proceeds from this offering, together with our existing cash and cash equivalents, willallow us to fund our operating plan for at least the next twelve months from the date of this prospectus. However, our operating plan may change as a result of factors currently unknown to us.Changing circumstances may cause us to consume capital faster or slower than we currently anticipate or to alter our operations. We have based these estimates on assumptions that may prove to bewrong, and we could utilize our available financial resources sooner than we currently expect.

        Therecan be no assurance that our revenue and expense forecasts will prove to be accurate, and any change in the foregoing assumptions could require us to obtain additional financingearlier than anticipated. There is a risk of delay or failure at any stage of developing a product candidate, and the time required and costs involved in successfully accomplishing our objectivescannot be accurately predicted. Actual drug research and development costs could substantially exceed budgeted amounts, which could force us to delay, reduce the scope of or eliminate one or more ofour research or development programs. Additionally, if the Cystic Fibrosis Foundation does not continue to provide sufficient level of funding support, we may not be able to complete thePhase 1/2a clinical trial relating to AR-501.

        Wemay never be able to generate a sufficient amount of product revenue to cover our expenses. Until we do, we expect to seek additional funding through public or private equity or debtfinancings, collaborative relationships, capital lease transactions or other available financingtransactions. However, there can be no assurance that additional financing will be available on acceptable terms, if at all, and such financings could be dilutive to existing security holders.Moreover, in the event that additional funds are obtained through arrangements with collaborators, such arrangements may require us to relinquish rights to certain of our technologies, productcandidates or products that we would otherwise seek to develop or commercialize ourselves.

        Ifadequate funds are not available, we may be required to delay, reduce the scope of or eliminate one or more of our research or development programs. Our failure to obtain adequatefinancing when needed and on acceptable terms would have a material adverse effect on our business, financial condition and results of operations.

Risks Relating to Manufacturing Activities

We have no experience manufacturing our product candidates at commercial scale, and there can be no assurancethat our product candidates can be manufactured in compliance with regulations at a cost or in quantities necessary to make them commercially viable. There can be no assurance that any contractmanufacturing facilities will be acceptable for licensure by regulatory authorities or that we can contract to build acceptable facilities.

        We have no experience in commercial-scale manufacturing of mAbs. We may develop our manufacturing capacity in part by building manufacturingfacilities. This activity would require substantial additional funds and we would need to hire and train significant numbers of qualified employees to staff these facilities. We may not be able todevelop commercial-scale manufacturing facilities that are adequate to produce materials for additional later-stage clinical trials or commercial use. We currently rely on CMOs for bulk productmanufacturing and sterile fill and finish of our products, and these contractors currently manufacture our product candidates at a scale

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thatis not adequate for commercial supply. Failure to find and maintain satisfactory commercial-scale manufacturing contractors could impair our ability to supply product for clinical and commercialneeds. Additionally, we may decide to outsource some or all of our bulk product manufacturing activities to a third party CMO. Failure of any of these contractors to maintain compliance with cGMPs andother regulatory and legal requirements could result in government actions that would limit or eliminate clinical trial and commercial product supply. Under any agreement with a CMO, we would haveless control over the timing and quality of manufacturing than if we were perform such manufacturing ourselves. A CMO would be manufacturing other pharmaceutical products in the same facilities as ourproduct candidates, increasing the risk of cross product contamination. Further, there is no guarantee that any CMO will continue ongoing operations, causing potential delays in product supply,reduced revenues and other liabilities for us.

        Theequipment and facilities employed in the manufacture of pharmaceuticals are subject to stringent qualification requirements by regulatory agencies, including validation of equipment,systems and processes. We may be subject to lengthy delays and expense in conducting validation studies, if we can meet the requirements at all.

        Ifwe are unable to manufacture or contract for a sufficient supply of our product candidates on acceptable terms, or if we encounter delays or difficulties in our manufacturingprocesses or our relationships with other manufacturers, our preclinical and clinical testing schedule would be delayed. This in turn would delay the submission of product candidates for regulatoryapproval and thereby delay the market introduction and subsequent sales of any products that receive regulatory approval, which would have a material adverse effect on our business, financialcondition and results of operations. Furthermore, we or our contract manufacturers must supply all necessary documentation in support of our regulatory approval applications on a timely basis and mustadhere to cGMP regulations enforced by the FDA and other regulatory bodies through their facilities inspection programs. If these facilities cannot pass a pre-approval plant inspection, the approvalby the FDA or other regulatory bodies of the products will not be granted. If the FDA or a comparable foreign regulatory authority does not approve our facilities and processes for the manufacture ofour product candidates or if they withdraw any such approval in the future, we may need to correct the issues or find alternative manufacturing facilities, which would significantly impact our abilityto develop, obtain regulatory approval for or market our product candidates, if approved.

Our contract manufacturers are subject to significant regulation with respect to manufacturing of ourproducts.

        All entities involved in the preparation of a product candidate for clinical trials or commercial sale, including our contract manufacturingorganizations used for bulk product manufacturing and filling and finishing of our bulk product, are subject to extensive regulation. Components of a finished product approved for commercial sale orused in late-stage clinical trials must be manufactured in accordance with cGMP. These regulations govern manufacturing processes and procedures, including record keeping, and the implementation andoperation of quality systems to control and assure the quality of investigational products and products approved for sale. The facilities and quality systems of some or all of our third-partycontractors must pass a pre-approval inspection for compliance with the applicable regulations as a condition of any regulatory approval of our product candidates. In addition, the regulatoryauthorities may, at any time, audit or inspect

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amanufacturing facility involved with the preparation of our product candidates or the associated quality systems for compliance with the regulations applicable to the activities being conducted. Theregulatory authorities also may, at any time following approval of a product for sale, audit the manufacturing facilities of our third-party contractors or raw material suppliers. If any suchinspection or audit identifies a failure to comply with applicable regulations or if a violation of our product specifications or applicable regulations occurs independent of such an inspection oraudit, the relevant regulatory authority may require remedial measures that may be costly and time-consuming to implement and that may include the temporary or permanent suspension of a clinical trialor commercial sales or the temporary or permanent closure of a facility. Our third-party contractors or raw material suppliers may refuse to implement remedial measures required by regulatoryauthorities. Any failure to comply with applicable manufacturing regulations or failure to implement required remedial measures imposed upon third parties with whom we contract could materially harmour business.

We rely on relationships with third-party contract manufacturers and raw material suppliers, which limits ourability to control the availability of, and manufacturing costs for, our product candidates.

        Problems with any of our contract manufacturers' or raw material suppliers' facilities or processes, could prevent or delay the production ofadequate supplies of finished products. This could delay clinical trials or delay and reduce commercial sales and materially harm our business. Any prolonged delay or interruption in the operations ofour collaborators' facilities or contract manufacturers' facilities could result in cancellation of shipments, loss of components in the process of being manufactured or a shortfall in availability ofa product candidate or products. A number of factors could cause interruptions, including, but not limited to:

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the inability of a supplier to provide raw materials;



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equipment malfunctions or failures at the facilities of our collaborators or suppliers;



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high process failure rates;



•

damage to facilities due to natural or man-made disasters;



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changes in regulatory requirements or standards that require modifications to our or our collaborators' and suppliers' manufacturing processes;



•

action by regulatory authorities or by us that results in the halting or slowdown of production of components or finished product at ourfacilities or the facilities of our collaborators or suppliers;



•

problems that delay or prevent manufacturing technology transfer to another facility, contract manufacturer or collaborator with subsequentdelay or inability to start up a commercial facility;



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a contract manufacturer or supplier going out of business, undergoing a capacity shortfall or otherwise failing to produce product ascontractually required;



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employee or contractor misconduct or negligence;



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shipping delays, losses or interruptions; and other similar factors.

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        Becausemanufacturing processes are complex and are subject to a lengthy regulatory approval process, alternative qualified production capacity and sufficiently trained or qualifiedpersonnel may not be available on a timely or cost-effective basis or at all. Difficulties or delays in ourcontract manufacturers' production of drug substances could delay our clinical trials, increase our costs, damage our reputation and cause us to lose revenue and market share if we are unable totimely meet market demand for any products that are approved for sale.

        Themanufacturing process for our product candidates has several components that are sourced from a single manufacturer. If we utilize an alternative manufacturer or alternativecomponent, we may be required to demonstrate comparability of the drug product before releasing the product for clinical use and we may not be to find an alternative supplier. For example, thestoppers used to seal the vials of our products are made by a single supplier using a proprietary formula and process. Any change to the stopper would require us to carry out lengthy studies to verifythat our product remains stable with the replacement stopper. The loss of any of our current suppliers could result in manufacturing delays for the component substitution, and we may need to acceptchanges in terms or price from our existing supplier in order to avoid such delays.

        Further,if our contract manufacturers are not in compliance with regulatory requirements at any stage, including post-marketing approval, we may be fined, forced to remove a productfrom the market and/or experience other adverse consequences, including delays, which could materially harm our business.

We use and generate hazardous materials in our business and must comply with environmental laws andregulations, which can be expensive.

        Our research, development and manufacturing involves the controlled use of hazardous materials, chemicals, various active microorganisms andvolatile organic compounds, and we may incur significant costs as a result of the need to comply with numerous laws and regulations. For example, as a pharmacologically-active material, any residualimpurities in process-waste streams must be disposed of as hazardous waste. We are subject to laws and regulations enforced by the FDA, the Drug Enforcement Agency, foreign health authorities andother regulatory requirements, including the Occupational Safety and Health Act, the Toxic Substances Control Act, the Resource Conservation and Recovery Act, and other current and potential federal,state, local and foreign laws and regulations governing the use, manufacture, storage, handling and disposal of our products, materials used to develop and manufacture our product candidates, andresulting waste products. Although we believe that our safety procedures for handling and disposing of such materials, and for killing any unused microorganisms before disposing of them, comply withthe standards prescribed by state and federal regulations, the risk of accidental contamination or injury from these materials cannot be completely eliminated. In the event of such an accident, wecould be held liable for any damages that result and any such liability could exceed our resources.

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During the course of the product life cycle we will make process changes to scale up manufacturing tocommercial manufacture or transfer the production to alternate sites or contract manufacturers. Our ability to successfully implement these changes will depend on our ability to demonstrate, to thesatisfaction of the FDA and other regulatory agencies that the product made by the new process or at the new site is comparable to the original product.

        In the event that manufacturing process changes are necessary for the further development of a product candidate, we may not be able to reachagreement with regulatory agencies on the criteria for demonstrating comparability to the original product, which would require us to repeat clinical studies performed with the original product. Thiscould result in lengthy delays in implementing the new process or site and consequent delays in regulatory approval and commercial sales of product derived from the new process. If we reach agreementwith regulatory agencies on the criteria for establishing comparability, we may not be able to meet these criteria or may suffer lengthy delays in meeting these criteria. This may result insignificant lost sales due to inability to meet commercial demand with the original product. Furthermore, studies to demonstrate comparability, or any other studies on the new process or site such asvalidation studies, may uncover findings that result in regulatory agencies delaying or refusing to approve the new process or site.

Risks Relating to Our Joint Venture Agreement

If our joint venture with Hepalink is not successful or if we fail to realize the benefits we anticipate fromsuch joint venture, we may not be able to capitalize on the full market potential of our products in China, Hong Kong, Macau and Taiwan.

        On February 11, 2018, we entered into a Joint Venture Contract, or the JV Agreement, with Shenzhen Hepalink PharmaceuticalGroup Co., Ltd., a People's Republic of China company, or Hepalink, pursuant to which we formed a Joint Venture company named Shenzen ArimabBioPharmaceuticals Co., Ltd., or SABC, a People's Republic of China Company, develop, manufacture, import and distribute AR-101 and AR-301 in China, Hong Kong, Macau and Taiwan,collectively, referred to as the Territory. The Joint Venture received regulatory approval in China and SABC was formed on July 2, 2018.

        Hepalinkcontributed the equivalent of $6.0 million in renminbi, the official currency of the People's Republic of China, and owns 51% of the capital of SABC and we contributed(i) $1.0 million in cash and (ii) a license to AR-101 and AR-301 pursuant to a Technology License and Collaboration Agreement between us and SABC and we own 49% of the capital ofSABC. In addition, Hepalink will provide SABC with clinical and regulatory personnel services for clinical and regulatory review, application and filing procedures in the Territory and we will provideclinical and regulatory personnel services to assist in coordination of the execution of the clinical study in China and also with CMC personnel services for drug supply and manufacturing planning.Upon the completion certain milestone events, which could occur as early as January 2019 and includes obtaining approval for a phase III clinical trial in mainland China, Hepalink will beobligated to contribute an equivalent of $9.0 million in renminbi in exchange for additional equity in SABC. If and to the extent these milestone events occur and Hepalink contributesadditional capital to SABC, our 49% ownership stake in SABC will be diminished in proportion to such investment.

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        WhileSABC is obligated to use its commercially best efforts to commercialize our products and product candidates in the Territory, we have limited contractual rights to direct itsactivities. Hepalink has the majority of the voting equity in SABC, and has the right to designate three of five board seats. Therefore, Hepalink may have a greater influence in the commercializationefforts and other operations of SABC. In general, our joint venture with Hepalink subjects us to a number of related risks including that:

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SABC may not commit sufficient resources to the marketing and distribution of our products in the Territory;



•

SABC may infringe the intellectual property rights of third parties, which may expose us to litigation and other potential liability;



•

our contribution of $1.0 million in cash to SABC, as long as we remain a shareholder of SABC, may not be transferred back to us or convertedinto USD and thus, may only be used for goods and services in China;



•

disputes may arise among SABC, Hepalink and us that result in the delay or termination of the commercialization of our products or productcandidates or that result in costly litigation or arbitration that diverts management attention and resources; and



•

SABC may not provide us with timely and accurate information regarding commercialization status or results, which could adversely impact ourability to manage our own commercialization efforts, accurately forecast financial results or provide timely information to our shareholders regarding our commercialization efforts in the Territory.

        Whilewe believe that our board representation, voting rights and other contractual rights with respect to SABC serve to mitigate some of these risks, we may have disagreements with theother directors and Hepalink that could impair our ability to influence SABC to act in a manner that we believe is in the best interests of our company. Upon the completion of certain milestoneevents, Hepalink will become obligated to acquire additional shares of SABC, the proceeds of which would be received by SABC in exchange for newly issued shares. We may not be able to access the fundsfor our own operations.

        Thelaws of the People's Republic of China, which govern SABC's management and operations, may not offer the same protections afforded to minority stockholders under the Delaware GeneralCorporation Law. Consequently, SABC may make business decisions that are not in our best interests as minority equityholders.

Risks Relating to Competitive Factors

We compete in an industry characterized by extensive research and development efforts and rapid technologicalprogress. New discoveries or commercial developments by our competitors could render our potential products obsolete or non-competitive.

        New developments occur and are expected to continue to occur at a rapid pace in our industry, and there can be no assurance that discoveries orcommercial developments by our competitors will not render some or all of our potential products obsolete or non-competitive, which could have a material adverse effect on our business, financialcondition and results of operations. New data from commercial and clinical-stage products continue to emerge and it is

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possiblethat these data may alter current standards of care, completely precluding us from further developing our product candidates or preventing us from getting them approved by regulatoryagencies. Further, it is possible that we may initiate a clinical trial or trials for our product candidates, only to find that data from competing products make it impossible for us to completeenrollment in these trials, resulting in our inability to file for marketing approval with regulatory agencies. Even if these products are approved for marketing in a particular indication orindications, they may have limited sales due to particularly intense competition in these markets.

        Weexpect to compete with fully integrated and well-established pharmaceutical and biotechnology companies in the near- and long-term. Most of these companies have substantially greaterfinancial, research and development, manufacturing and marketing experience and resources than we do and represent substantial long-term competition for us. Such companies may succeed in discoveringand developing pharmaceutical products more rapidly than we do or pharmaceutical products that are safer, more effective or less costly than any that we may develop. Such companies also may be moresuccessful than we are in manufacturing, sales and marketing. Smaller companies may also prove to be significant competitors, particularly through collaborative arrangements with large pharmaceuticaland established biotechnology companies. Academic institutions, governmental agencies and other public and private research organizations also conduct clinical trials, seek patent protection andestablish collaborative arrangements for the development of product candidates.

        Weexpect competition among products will be based on product efficacy and safety, the timing and scope of regulatory approvals, availability of supply, marketing and sales capabilities,reimbursement coverage, price and patent position. There can be no assurance that our competitors will not develop safer and more effective products, commercialize products earlier than we do, orobtain patent protection or intellectual property rights that limit our ability to commercialize our products.

        Therecan be no assurance that our issued patents or pending patent applications, if issued, will not be challenged, invalidated or circumvented or that the rights granted thereunderwill provide us with proprietary protection or a competitive advantage.

Our competitors may develop and market products that are less expensive, more effective, safer or reach themarket sooner than our product candidates, which may diminish or eliminate the commercial success of any products we may commercialize.

        The biopharmaceutical industry is highly competitive. There are many public and private biopharmaceutical companies, public and privateuniversities and research organizations actively engaged in the discovery and research and development of products for infectious disease. Several companies are developing mAbs to treat infections,including Merck & Co., Medimmune, LLC (AstraZeneca), Arsanis, Inc., and Alopexx Enterprises, LLC.

        Thereis no assurance, however, that another company will not discover how to successfully develop these antibodies for competing indications.

        Amongcurrent antimicrobial therapies, antibiotics, particularly those administered by inhalation, can be competitors to our products especially Panaecin for lung infections. TOBI, aninhaled antibiotic (tobramycin) has the longest treatment history, although Cayston (inhaled aztreonam) was recently approved for lung infections in cystic fibrosis patients. There are

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antibioticsbeing developed for gram-positive or gram-negative bacterial infections that could impact the use of standard of care antibiotics in hospitals. These therapies could impact both theclinical results and use of our products being developed for hospital acquired pneumonia.

        Manyof our competitors, either alone or with their strategic collaborators, have substantially greater financial, technical and human resources than we do and significantly greaterexperience in the discovery and development of drugs, obtaining FDA and other regulatory approvals, and the commercialization of those products. Accordingly, our competitors may be more successful inobtaining approval for drugs and achieving widespread market acceptance. Our competitors' drugs may be more effective, or more effectively marketed and sold, than any drug we may commercialize and mayrender our product candidates obsolete or non-competitive before we can recover the significant expenses of developing and commercializing any of our product candidates. We anticipate that we willface intense and increasing competition as new drugs enter the market and advanced technologies become available.

        Wealso compete with other clinical-stage companies and institutions for clinical trial participants, which could reduce our ability to recruit participants for our clinical trials.Delay in recruiting clinical trial participants could adversely affect our ability to bring a product to market prior to our competitors. Further, research and discoveries by others may result inbreakthroughs that render our product candidates obsolete even before they begin to generate any revenue.

        Inaddition, our competitors may obtain patent protection or FDA approval and commercialize products more rapidly than we do, which may impact future sales of any of our productcandidates that receive marketing approval. If the FDA approves the commercial sale of any of our product candidates, we will also be competing with respect to marketing capabilities and manufacturingefficiency, areas in which we have limited or no experience. We expect competition among products will be based on product efficacy and safety, the timing and scope of regulatory approvals,availability of supply, marketing and sales capabilities, product price, reimbursementcoverage by government and private third-party payors, and patent position. Our profitability and financial position will suffer if our products receive regulatory approval, but cannot competeeffectively in the marketplace.

        Ifany of our product candidates are approved and commercialized, we may face competition from biosimilars. The route to market for biosimilars was established with the passage of thePatient Protection and Affordable Care Act, or PPACA, in March 2010, providing 12 years of marketing exclusivity for reference products and an additional six months of exclusivity if pediatricstudies are conducted. In the EU, the EMA has issued guidelines for approving products through an abbreviated pathway, and biosimilars have been approved. If a biosimilar version of one of ourpotential products were approved in the U.S. or EU, it could have a negative effect on sales and gross profits of the potential product and our financial condition.

Even if we achieve market acceptance for our products, we may experience downward pricing pressure on theprice of our drugs because of generic and biosimilar competition and social pressure to lower the cost of drugs.

        Several of the FDA approved products for infectious diseases face patent expiration in the next several years. As a result, generic versions andbiosimilars of these drugs and biologicals may become available. We expect to face competition from these products, including price-based

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competition.Pressure from government and private reimbursement groups, plus patient awareness and other social activist groups to reduce drug prices may also put downward pressure on the prices ofdrugs, including our product candidates, if they are commercialized. Also, if a biosimilar to any of our product candidates is approved by regulatory agencies, there will be significant pricingpressure on our products, causing us or our collaborators to reduce the sales price of our products.

Our product candidates may not be accepted in the marketplace; therefore, we may not be able to generatesignificant revenue, if any.

        Even if our product candidates are approved for sale, physicians and the medical community may not ultimately use them or may use them only inapplications more restricted than we expect. Our product candidates, if successfully developed, will compete with a number of traditional products, including antibiotics, and immunotherapiesmanufactured and marketed by major pharmaceutical and other biotechnology companies. Our product candidates will also compete with new products currently under development by such companies andothers. Physicians will prescribe a product only if they determine, based on experience, clinical data, side effect profiles, reimbursement for their patients and other factors, that it is beneficialas compared to other products currently in use. Furthermore, physicians have been prescribing traditional antibiotics for decades and may be resistant to switching to new, less established therapies.Many other factors influence the adoption of new products, including marketing and distribution restrictions, course of treatment, adverse publicity, product pricing, the views of thought leaders inthe medical community and reimbursement by government and private third-party payors.

Risks Relating to our Reliance on Third Parties

We rely on third parties to conduct our preclinical studies and our clinical trials and to store anddistribute our products for the clinical trials we conduct. If these third parties do not perform as contractually required or expected, we may not be able to obtain regulatory approval for ourproduct candidates, or we may be delayed in doing so.

        We often rely on third parties, such as CROs, medical institutions, academic institutions, clinical investigators and contract laboratories, toconduct our preclinical studies and clinical trials. We are responsible for confirming that our preclinical studies are conducted in accordance with applicable regulations and that each of ourclinical trials is conducted in accordance with its general investigational plan and protocol. The FDA requires us to comply with Good Laboratory Practice for conducting and recording the results ofour preclinical studies and Good Clinical Practices, or GCP, for conducting, monitoring, recording and reporting the results ofclinical trials, to ensure that data and reported results are accurate and that the clinical trial participants are adequately protected. Our reliance on third parties does not relieve us of theseresponsibilities. If the third parties conducting our clinical trials do not perform their contractual duties or obligations, do not meet expected deadlines, fail to comply with GCP, do not adhere toour clinical trial protocols or otherwise fail to generate reliable clinical data, we may need to enter into new arrangements with alternative third parties and our clinical trials may be more costlythan expected or budgeted, extended, delayed or terminated or may need to be repeated, and we may not be able to obtain regulatory approval for or commercialize the product candidate being tested insuch trials.

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        OurCROs are not our employees, and we are therefore unable to directly monitor whether or not they devote sufficient time and resources to our clinical and preclinical programs. TheseCROs may also have relationships with other commercial entities, including our competitors, for whom they may also be conducting clinical trials or other product development activities that could harmour competitive position. If our CROs do not successfully carry out their contractual duties or obligations, fail to meet expected deadlines, or if the quality or accuracy of the clinical data theyobtain is compromised due to the failure to adhere to our clinical protocols or regulatory requirements, or for any other reasons, our clinical trials may be extended, delayed or terminated, and wemay not be able to obtain regulatory approval for, or successfully commercialize, our therapeutic candidates. If any such event were to occur, our financial results and the commercial prospects forour therapeutic candidates would be harmed, our costs could increase, and our ability to generate revenues could be delayed.

        Ifany of our relationships with these third-party CROs terminate, we may not be able to enter into arrangements with alternative CROs or to do so on commercially reasonable terms.Further, switching or adding additional CROs involves additional costs and requires management time and focus. In addition, there is a natural transition period when a new CRO commences work. As aresult, delays occur, which could materially impact our ability to meet our desired clinical development timelines. Though we carefully manage our relationships with our CROs, there can be noassurance that we will not encounter challenges or delays in the future or that these delays or challenges will not have a material adverse impact on our business, financial condition and prospects.

        Inaddition, our future clinical trials will require a sufficient number of test subjects to evaluate the safety and effectiveness of our therapeutic candidates. Accordingly, if our CROsfail to complywith these regulations or fail to recruit a sufficient number of patients, we may be required to repeat such clinical trials, which would delay the regulatory approval process.

        Wealso rely on other third parties to store and distribute our products for the clinical trials that we conduct. Any performance failure on the part of our distributors could delayclinical development or marketing approval of our therapeutic candidates or commercialization of our products, if approved, producing additional losses and depriving us of potential product revenue.

We may explore new strategic collaborations that may never materialize or may fail.

        We may, in the future, periodically explore a variety of new strategic collaborations in an effort to gain access to additional productcandidates or resources. At the current time, we cannot predict what form such a strategic collaboration might take. We are likely to face significant competition in seeking appropriate strategiccollaborators, and these strategic collaborations can be complicated and time-consuming to negotiate and document. We may not be able to negotiate strategic collaborations on acceptable terms, or atall. We are unable to predict when, if ever, we will enter into any additional strategic collaborations because of the numerous risks and uncertainties associated with establishing strategiccollaborations.

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Risks Relating to our Exposure to Litigation

We are exposed to potential product liability or similar claims, and insurance against these claims may notbe available to us at a reasonable rate in the future.

        Our business exposes us to potential liability risks that are inherent in the testing, manufacturing and marketing of human therapeuticproducts. Clinical trials involve the testing of product candidates on human subjects or volunteers under a research plan, and carry a risk of liability for personal injury or death to patients due tounforeseen adverse side effects, improper administration of the product candidate, or other factors. Many of these patients are already seriously ill and are therefore particularly vulnerable tofurther illness or death.

        OurU.S. clinical trial liability insurance provides for $3 million in coverage with no per occurrence limit below that amount, our Belgium clinical trial liability insuranceprovides for €3.5 million ($4.2 million) in coverage with a limit of €1 million ($1.2 million) per occurrence, our France clinical trialliability insurance provides for €6 million ($7.2 million) in coverage with a limit of €1 million ($1.2 million) per occurrence, our Spainclinical trial liability insurance provides for €2.5 million ($3.0 million) in coverage with a limit of €0.25 million ($0.3 million) peroccurrence and our U.K. clinical trial insurance provides for £5 million ($6.75 million) in coverage with a limit of £5 million ($6.75 million) peroccurrence. However, there can be no assurance that we will be able to maintain such insurance or that the amount of such insurance will be adequate to cover claims. We could be materially andadversely affected if we were required to pay damages or incur defense costs in connection with a claim outside the scope of indemnity or insurance coverage, if the indemnity is not performed orenforced in accordance with its terms, or if our liability exceeds the amount of applicable insurance. In addition, there can be no assurance that insurance will continue to be available on termsacceptable to us, if at all, or that if obtained, the insurance coverage will be sufficient to cover any potential claims or liabilities. Similar risks would exist upon the commercialization ormarketing of any products by us or our collaborators.

        Regardlessof their merit or eventual outcome, product liability claims may result in:

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decreased demand for our product;



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injury to our reputation and significant negative media attention;



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withdrawal of clinical trial volunteers;



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costs of litigation;



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distraction of management; and



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substantial monetary awards to plaintiffs.

        Shouldany of these events occur, it could have a material adverse effect on our business and financial condition.

Claims for indemnification by our directors and officers may reduce our available funds to satisfy successfulthird-party claims against us and may reduce the amount of money available to the Company.

        Our certificate of incorporation provides that we will indemnify our directors to the fullest extent permitted by Delaware law.

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        In addition, as permitted by Section 145 of the Delaware General Corporation Law, our bylaws provide that:

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we may, in our discretion, indemnify other officers, employees and agents in those circumstances where indemnification is permitted byapplicable law;



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we are required to advance expenses, as incurred, to our directors and executive officers in connection with defending a proceeding, exceptthat such directors or executive officers shall undertake to repay such advances if it is ultimately determined that such person is not entitled to indemnification;



•

we will not be obligated pursuant to our bylaws to indemnify any director or executive officer in connection with any proceeding (or partthereof) initiated by such person unless (i) such indemnification is expressly required to be made by law, (ii) the proceeding was authorized by our Board of Directors, (iii) suchindemnification is provided by us, in our sole discretion, pursuant to the powers vested in the corporation under applicable law or (iv) such indemnification is required to be made pursuant toour amended and restated bylaws;



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the rights conferred in our bylaws are not exclusive, and we are authorized to enter into indemnification agreements with our directors,officers, employees and agents and to obtain insurance to indemnify such persons; and



•

we may not retroactively amend our bylaw provisions to reduce our indemnification obligations to directors, officers, employees and agents.

        Asa result, if we are required to indemnify one or more of our directors or executive officers, it may reduce our available funds to satisfy successful third-party claims against us,may reduce the amount of money available to us and may have a material adverse effect on our business and financial condition.

Risks Relating to Regulation of Our Industry

The biopharmaceutical industry is subject to significant regulation and oversight in theUnited States, in addition to approval of products for sale and marketing. We may be subject, directly or indirectly, to federal and state healthcare fraud and abuse laws, transparency, healthinformation privacy and security laws and other healthcare laws and regulations. If we are unable to comply, or have not fully complied, with such laws, we could face substantial penalties.

        Healthcare providers, physicians and third-party payors will play a primary role in the recommendation and prescription of any future productcandidates we may develop and any product candidates for which we obtain marketing approval. In addition to FDA restrictions on marketing of biopharmaceutical products, we are exposed, directly, orindirectly, through our customers, to broadly applicable fraud and abuse and other healthcare laws and regulations that may affect the business or financial arrangements and relationships throughwhich we would market, sell and distribute our products. The laws that may affect our ability to operate include, but are not limited to:

        Thefederal Anti-Kickback Statute which prohibits any person or entity from, among other things, knowingly and willfully offering, paying, soliciting or receiving any remuneration,directly or

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indirectly,overtly or covertly, in cash or in-kind, to induce or reward either the referring of an individual for, or the purchasing, leasing, ordering or arranging for the purchase, lease or orderof any health care item or service reimbursable, in whole or in part, under Medicare, Medicaid or any other federally financed healthcare program. The term "remuneration" has been broadly interpretedto include anything of value. This statute has been interpreted to apply to arrangements between pharmaceutical manufacturers on one hand and prescribers, purchasers and formulary managers on theother hand. Although there are a number of statutory exceptions and regulatory safe harbors protecting certain common activities from prosecution, the exceptions and safe harbors are drawn narrowly,and practices that involve remuneration intended to induce prescribing, purchases or recommendations may be subject to scrutiny if they do not qualify for an exception or safe harbor. Our practicesmay not in all cases meet all of the criteria for safe harbor protection from federal Anti-Kickback Statute liability.

        Thefederal false claims and civil monetary penalty laws, including the Federal False Claims Act, which imposes significant penalties and can be enforced by private citizens throughcivil qui tam actions, prohibits any person or entity from, among other things, knowingly presenting, or causing to be presented, a false, fictitious or fraudulent claim for payment to the federalgovernment, or knowingly making, using or causing to be made, a false statement or record material to a false or fraudulent claim to avoid, decrease or conceal an obligation to pay money to thefederal government. In addition, a claim including items or services resulting from a violation of the federal Anti-Kickback Statute constitutes a false or fraudulent claim for purposes of the FederalFalse Claims Act. As a result of a modification made by the Fraud Enforcement and Recovery Act of 2009, a claim includes "any request or demand" for money or property presented to the U.S. government.Further, manufacturers can be held liable under the False Claims Act even when they do not submit claims directly to government payors if they are deemed to "cause" the submission of false orfraudulent claims. Criminal prosecution is also possible for making or presenting a false, fictitious or fraudulent claim to the federal government. Several pharmaceutical and other health carecompanies have been prosecuted under these laws for allegedly providing free product to customers with the expectation that the customers would bill federal programs for the product. Other companieshave been prosecuted for causing false claims to be submitted because of marketing of the product for unapproved, and thus non-reimbursable, uses.

        Thefederal Health Insurance Portability and Accountability Act of 1996, or HIPAA, which, among other things, imposes criminal liability for executing or attempting to execute a schemeto defraud any healthcare benefit program, including private third-party payors, knowingly and willfully embezzling or stealing from a healthcare benefit program, willfully obstructing a criminalinvestigation of a healthcare offense, and creates federal criminal laws that prohibit knowingly and willfully falsifying, concealing or covering up a material fact or making any materially false,fictitious or fraudulent statements or representations, or making or using any false writing or document knowing the same to contain any materially false, fictitious or fraudulent statement or entryin connection with the delivery of or payment for healthcare benefits, items or services.

        HIPAA,as amended by the Health Information Technology for Economic and Clinical Health Act of 2009, or HITECH, and its implementing regulations, which impose certain requirementsrelating to the privacy, security, transmission and breach reporting of individually identifiable health information upon entities subject to the law, such as health plans, healthcare clearinghousesand certain healthcare providers and their respective business associates that perform services for

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themthat involve individually identifiable health information. HITECH also created new tiers of civil monetary penalties, amended HIPAA to make civil and criminal penalties directly applicableto business associates, and gave state attorneys general new authority to file civil actions for damages or injunctions in U.S. federal courts to enforce the federal HIPAA laws and seek attorneys'fees and costs associated with pursuing federal civil actions.

        Thefederal physician payment transparency requirements, sometimes referred to as the "Physician Payments Sunshine Act," and its implementing regulations, which require certainmanufacturers of drugs, devices, biologics and medical supplies for which payment is available under Medicare, Medicaid or the Children's Health Insurance Program (with certain exceptions) to reportannually to the United States Department of Health and Human Services, or HHS, information related to payments or other transfers of value made to physicians (defined to include doctors,dentists, optometrists, podiatrists and chiropractors) and teaching hospitals, as well as ownership and investment interests held by physicians and their immediate family members.

        Stateand foreign law equivalents of each of the above federal laws, such as anti-kickback and false claims laws, that may impose similar or more prohibitive restrictions, and may applyto items or services reimbursed by non-governmental third-party payors, including private insurers.

        Statelaws that require pharmaceutical companies to implement compliance programs, comply with the pharmaceutical industry's voluntary compliance guidelines and the relevant complianceguidance promulgated by the federal government, or to track and report gifts, compensation and other remuneration provided to physicians and other healthcare providers, state and local laws thatrequire the registration of pharmaceutical sales representatives, and other federal, state and foreign laws that govern the privacy and security of health information or personally identifiableinformation in certain circumstances, including state health information privacy and data breach notification laws which govern the collection, use, disclosure, and protection of health-related andother personal information, many of which differ from each other in significant ways and often are not pre-empted by HIPAA, thus requiring additional compliance efforts.

        Becauseof the breadth of these laws and the narrowness of the safe harbors, it is possible that some of our business activities could be subject to challenge under one or more of theselaws. The scope and enforcement of each of these laws is uncertain and subject to rapid change in the current environment of healthcare reform, especially in light of the lack of applicable precedentand regulations. Federal and state enforcement bodies have recently increased their scrutiny of interactions between healthcare companies and healthcare providers, which has led to a number ofinvestigations, prosecutions, convictions and settlements in the healthcare industry.

        Ensuringthat our business arrangements with third parties comply with applicable healthcare laws and regulations will likely be costly and time consuming. If our operations are found tobe in violation of any of the laws described above or any other governmental regulations that apply tous, we may be subject to penalties, including civil, criminal and administrative penalties, damages, fines, disgorgement, individual imprisonment, exclusion from governmental funded healthcareprograms, such as Medicare and Medicaid, contractual damages, reputational harm, diminished profits and future earnings, additional reporting obligations and oversight if we become subject to acorporate integrity agreement or other agreement to resolve allegations of non-compliance with these laws, and the curtailment or restructuring of our operations, any of which could adversely affectour ability to operate our business and our results of operations.

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Our employees may engage in misconduct or other improper activities, including noncompliance with regulatorystandards and requirements, which could have a material adverse effect on our business.

        We are exposed to the risk of employee fraud or other misconduct. Misconduct by employees could include intentional failures to comply with FDAregulations, provide accurate information to the FDA, comply with manufacturing standards we have established, comply with federal and state health-care fraud and abuse laws and regulations, reportfinancial information or data accurately or disclose unauthorized activities to us. In particular, sales, marketing and business arrangements in the healthcare industry are subject to extensive lawsand regulations intended to prevent fraud, kickbacks, self-dealing and other abusive practices. These laws and regulations may restrict or prohibit a wide range of pricing, discounting, marketing andpromotion, sales commission, customer incentive programs and other business arrangements. Employee misconduct could also involve the improper use of information obtained in the course of clinicaltrials, which could result in regulatory sanctions and serious harm to our reputation. It is not always possible to identify and deter employee misconduct, and the precautions we take to detect andprevent misconduct may not be effective in controlling unknown or unmanaged risks or losses or in protecting us from governmental investigations or other actions or lawsuits stemming from a failure tobe in compliance with such laws or regulations. If any such actions are instituted against us, and we are not successful in defending ourselves or asserting our rights, those actions could have asignificant impact on our business and results of operations, including the imposition of significant civil, criminal, and administrative penalties, damages, fines, disgorgement, individualimprisonment, exclusion from governmental funded healthcare programs, such as Medicare and Medicaid, contractual damages, reputational harm, diminished profits and future earnings, additionalreporting obligations and oversight if subject to a corporate integrity agreement or other agreement to resolve allegations of non-compliance with these laws.

Health care reform measures could adversely affect our business.

        In the United States and foreign jurisdictions, there have been, and continue to be, a number of legislative and regulatory changes andproposed changes to the healthcare system that could affect our future results of operations. In particular, there have been and continue to be a number of initiatives at the U.S. federal and statelevels that seek to reduce healthcare costs. In 2010, the PPACA was enacted, which includes measures to significantly change the way health care is financed by both governmental and private insurers.Among the provisions of the PPACA of greatest importance to the pharmaceutical and biotechnology industry are the following:

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an annual, nondeductible fee on any entity that manufactures or imports certain branded prescription drugs and biologic agents, apportionedamong these entities according to their market share in certain government healthcare programs;



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implementation of the federal physician payment transparency requirements, sometimes referred to as the "Physician Payments Sunshine Act";



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a licensure framework for follow-on biologic products;



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a new Patient-Centered Outcomes Research Institute to oversee, identify priorities in, and conduct comparative clinical effectiveness research,along with funding for such research;

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establishment of a Center for Medicare Innovation at the Centers for Medicare & Medicaid Services to test innovative payment and servicedelivery models to lower Medicare and Medicaid spending, potentially including prescription drug spending;



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an increase in the statutory minimum rebates a manufacturer must pay under the Medicaid Drug Rebate Program, to 23.1% and 13% of the averagemanufacturer price for most branded and generic drugs, respectively and capped the total rebate amount for innovator drugs at 100% of the Average Manufacturer Price, or AMP;



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a new methodology by which rebates owed by manufacturers under the Medicaid Drug Rebate Program are calculated for certain drugs and biologics,including our product candidates, that are inhaled, infused, instilled, implanted or injected;



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extension of manufacturers' Medicaid rebate liability to covered drugs dispensed to individuals who are enrolled in Medicaid managed careorganizations;



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expansion of eligibility criteria for Medicaid programs by, among other things, allowing states to offer Medicaid coverage to additionalindividuals and by adding new mandatory eligibility categories for individuals with income at or below 133% of the federal poverty level, thereby potentially increasing manufacturers' Medicaid rebateliability;



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a new Medicare Part D coverage gap discount program, in which manufacturers must agree to offer 50% (and 70% commencing January 1, 2019)point-of-sale discounts off negotiated prices of applicable brand drugs to eligible beneficiaries during their coverage gap period, as a condition for the manufacturer's outpatient drugs to be coveredunder Medicare Part D; and



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expansion of the entities eligible for discounts under the Public Health program.

        Someof the provisions of the PPACA have yet to be implemented, and there have been legal and political challenges to certain aspects of the PPACA. Since January 2017, President Trumphas signed two executive orders and other directives designed to delay, circumvent, or loosen certain requirements mandated by the PPACA. Concurrently, Congress has considered legislation that wouldrepeal or repeal and replace all or part of the PPACA. While Congress has not passed repeal legislation two bills affecting the implementation of certain taxes under the PPACA have been signed intolaw. The Tax Cuts and Jobs Act of 2017 includes a provision repealing, effective January 1, 2019, the tax-based shared responsibility payment imposed by the PPACA on certain individuals whofail to maintain qualifying health coverage for all or part of a year that is commonly referred to as the "individual mandate." Additionally, on January 22, 2018, President Trump signed a continuingresolution on appropriations for fiscal year 2018 that delayed the implementation of certain PPACA-mandated fees, including the so-called "Cadillac" tax on certain high cost employer-sponsoredinsurance plans, the annual fee imposed on certain health insurance providers based on market share, and the medical device excise tax on non-exempt medical devices. Further, the Bipartisan Budget Actof 2018, or the BBA, among other things, amends the PPACA, effective January 1, 2019, to close the coverage gap in most Medicare drug plans, commonly referred to as the "donut hole." Congress mayconsider other legislation to repeal or replace elements of the PPACA.

        Manyof the details regarding the implementation of the PPACA are yet to be determined, and at this time, the full effect that the PPACA would have on our business remains unclear. In

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particular,there is uncertainty surrounding the applicability of the biosimilars provisions under the PPACA to our product candidates. The FDA has issued several guidance documents, and withdrawnothers, but no implementing regulations on biosimilars have been adopted. A number of biosimilar applications have been approved over the past few years. It is not certain that we will receive12 years of biologics marketing exclusivity for any of our products. The regulations that are ultimately promulgated and their implementation are likely to have considerable impact on the waywe conduct our business and may require us to change current strategies. A biosimilar is a biological product that is highly similar to an approved drug notwithstanding minor differences in clinicallyinactive components, and for which there are no clinically meaningful differences between the biological product and the approved drug in terms of the safety, purity, and potency of the product.

        Additionally,there has been heightened governmental scrutiny in the United States of pharmaceutical pricing practices in light of the rising cost of prescription drugs and biologics.Such scrutiny has resulted in several recent congressional inquiries and proposed and enacted federal and state legislation designed to, among other things, bring more transparency to product pricing,review the relationship between pricing and manufacturer patient programs, and reform government program reimbursement methodologies for products. At the federal level, the Trump administration'sbudget proposal for fiscal year 2019 contains further drug price control measures that could be enacted during the 2019 budget process or in other future legislation, including, for example, measuresto permit Medicare Part D plans to negotiate the price of certain drugs under Medicare Part B, to allow some states to negotiate drug prices under Medicaid, and to eliminate cost sharing for genericdrugs for low-income patients. Further, the Trump administration released a "Blueprint" to lower drug prices and reduce out of pocket costs of drugs that contains additional proposals to increase drugmanufacturer competition, increase the negotiating power of certain federal healthcare programs, incentivize manufacturers to lower the list price of their products and reduce the out of pocket costsof drug products paid by consumers. HHS has already started the process of soliciting feedback on some of these measures and, at the same, is immediately implementing others under its existingauthority. Although a number of these, and other potential, proposals will require authorization through additional legislation to become effective, Congress and the Trump administration have eachindicated that it will continue to seek new legislative and/or administrative measures to control drug costs. At the state level, legislatures have become increasingly aggressive in passinglegislation and implementing regulations designed to control pharmaceutical and biological product pricing, including price or patient reimbursement constraints, discounts, restrictions on certainproduct access, and marketing cost disclosure and transparency measures, and to encourage importation from other countries and bulk purchasing. Legally mandated price controls on payment amounts bythird-party payors or other restrictions could harm our business, results of operations, financial condition and prospects. In addition,regional healthcare authorities and individual hospitals are increasingly using bidding procedures to determine what pharmaceutical products and which suppliers will be included in their prescriptiondrug and other healthcare programs. This could reduce ultimate demand for our products or put pressure on our product pricing, which could negatively affect our business, results of operations,financial condition and prospects.

        Morerecently, on May 30, 2018, the Trickett Wendler, Frank Mongiello, Jordan McLinn, and Matthew Bellina Right to Try Act of 2017 ("Right to Try Act") was signed into law. Thelaw,

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amongother things, provides a federal framework for certain patients to access certain investigational new drug products that have completed a Phase I clinical trial and that are undergoinginvestigation for FDA approval. Under certain circumstances, eligible patients can seek treatment without enrolling in clinical trials and without obtaining FDA permission under the FDA expandedaccess program.

        Inaddition, given recent federal and state government initiatives directed at lowering the total cost of healthcare, Congress and state legislatures will likely continue to focus onhealthcare reform, the cost of prescription drugs and biologics and the reform of the Medicare and Medicaid programs. While we cannot predict the full outcome of any such legislation, it may result indecreased reimbursement for drugs and biologics, which may further exacerbate industry-wide pressure to reduce prescription drug prices. This could harm our ability to generate revenues. Increases inimportation or re-importation of pharmaceutical products from foreign countries into the United States could put competitive pressure on our ability to profitably price our products, which, inturn, could adversely affect our business, results of operations, financial condition and prospects. We might elect not to seek approval for or market our products in foreign jurisdictions in order tominimize the risk of re-importation, which could also reduce the revenue we generate from our product sales. It is also possible that other legislative proposals having similar effects will beadopted.

        Furthermore,regulatory authorities' assessment of the data and results required to demonstrate safety and efficacy can change over time and can be affected by many factors, such as theemergence of new information, including on other products, changing policies and agency funding, staffing and leadership. We cannot be sure whether future changes to the regulatory environment will befavorable or unfavorable to our business prospects. For example, average review times atthe FDA for marketing approval applications can be affected by a variety of factors, including budget and funding levels and statutory, regulatory and policy changes.

Risks Relating to Protecting our Intellectual Property

If we are unable to protect our proprietary rights or to defend against infringement claims, we may not beable to compete effectively or operate profitably.

        Our success will depend, in part, on our ability to obtain patents, operate without infringing the proprietary rights of others and maintaintrade secrets or other proprietary know-how, both in the United States and other countries. Patent matters in the biotechnology and pharmaceutical industries can be highly uncertain, caninvolve changes in laws or regulations, and involve complex legal and factual questions. Accordingly, the issuance, validity, breadth and enforceability of our patents and the existence of potentiallyblocking patent rights of others cannot be predicted with any degree of certainty, either in the United States or in other countries.

        Obtaining,maintaining, and enforcing patents is expensive and time-consuming, and we may not be able to file and prosecute all necessary or desirable patent applications, or maintain,enforce and/or license patents that may issue based on our patent applications, at a reasonable cost or in a timely manner. It is also possible that we will fail to identify patentable aspects of ourresearch and development results before it is too late to obtain patent protection. Moreover, in some circumstances, we may not have the right to control the preparation, filing and prosecution ofpatent applications, or to maintain the patents, covering technology that we license from or

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licenseto third parties and are reliant on our licensors or licensees. Further, although we enter into non-disclosure and confidentiality agreements with parties who have access to patentableaspects of our research and development output, such as our employees, corporate collaborators, outside scientific collaborators, contract research organizations, contract manufacturers, consultants,advisors and other third parties, any of these parties may breach these agreements and disclose such results before a patent application is filed, thereby jeopardizing our ability to seek patentprotection.

        Therecan be no assurance that we will discover or develop patentable products or processes or that patents will issue from any of the currently pending patent applications or thatclaims granted on issued patents will be sufficient to protect our technologies, processes, or adequately cover the actual products we may actually sell. Potential competitors or other researchers inthe field may have filed patent applications, been issued patents, published articles or otherwise created prior art that could restrict or block our efforts to obtain additional patents or act asobstacles to our pending patent applications. There also can be no assurance that our issued patents or pending patent applications, if issued, will not be challenged, invalidated, renderedunenforceable or not infringed, or that the rights granted thereunder will provide us with proprietary protection or competitive advantages. We may not be aware of all third-party intellectualproperty rights potentially relating to our product candidates or their intended uses, and as a result the impact of such third-party intellectual property rights upon the patentability of our ownpatents and patent applications, as well as the impact of such third-party intellectual property upon our freedom to operate, is highly uncertain. Patent applications in the U.S. and otherjurisdictions are typically not published until 18 months after filing or, in some cases, not at all. Therefore, we cannot know with certainty whether we were the first to make the inventionsclaimed in our patents or pending patent applications, or that we were the first to file for patent protection of such inventions. As a result, the issuance, scope, validity, enforceability andcommercial value of our patent rights are highly uncertain. Our patents or pending patent applications may be challenged in the courts or patent offices in the U.S. and abroad. For example, we may besubject to a third party pre-issuance submission of prior art to the U.S. Patent and Trademark Office, or become involved in post-grant review procedures, oppositions, derivations, reexaminations,inter partes review or interference proceedings, in the U.S. or elsewhere, challenging our patent rights or the patent rights of others. An adverse determination in any such challenges may result inloss of exclusivity or in patent claims being narrowed, invalidated, or held unenforceable, in whole or in part, which could limit our ability to stop others from using or commercializing similar oridentical technology and products, or limit the duration of the patent protection of our technology and products. In addition, given the amount of time required for the development, testing andregulatory review of new product candidates, patents protecting such candidates might expire before or shortly after such candidates are commercialized. The patent position of biopharmaceuticalcompanies generally is highly uncertain, involves complex legal and factual questions and has in recent years been the subject of much litigation, resulting in court decisions, including Supreme Courtdecisions, that have increased uncertainties as to the ability to enforce patent rights in the future. In addition, the laws of foreign countries may not protect our rights to the same extent as thelaws of the U.S., or vice versa. Our patent rights also depend on our compliance with technology and patent licenses upon which our patent rights are based and upon the validity of assignments ofpatent rights from consultants and other inventors that were, or are, not employed by us.

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        Inaddition, competitors may manufacture and sell our potential products in those foreign countries where we have not filed for patent protection or where patent protection may beunavailable, not obtainable or ultimately not enforceable or meaningful. In addition, even where patent protection is obtained, third-party competitors may challenge our patent claims in the variouspatent offices, for example via opposition in the European Patent Office or reexamination or interference proceedings in the United States Patent and Trademark Office, or USPTO, or find ways todesign around our patents by producing competitive non-infringing alternative products. The ability of such competitors to sell such products in the United States or in foreign countries wherewe have obtained patents is usually governed by the patent laws of the countries in which the product is sold.

        Wewill incur significant ongoing expenses in maintaining our patent portfolio in addition to maintaining other registered intellectual property such as trademarks and copyrights.Maintaining registered intellectual property such as patents and trademarks requires timely filing certain maintenance documents and paying certain maintenance fees, the failure of which could resultin abandonment or cancellation of such registered intellectual property. Should we lack the funds to maintain our patent portfolio or other registered intellectual property, or to enforce our rightsagainst infringers, we could be adversely impacted. Even if we succeed in enforcing one of our patents against a third party in a claim of infringement, any such action could divert the time andattention of management and impair our ability to access additional capital and/or cost us significant funds.

If we cannot meet requirements under our license and sublicense agreements, we could lose the rights to ourproducts, which could have a material adverse effect on our business.

        We depend on licensing and sublicensing agreements with third parties such as the University of Chicago, University of Iowa, Brigham and Women'sHospital, Inc., Brigham Young University, Public Health Service and Kenta Biotech Ltd to maintain the intellectual property rights to certain of our product candidates. These agreements require us tomake payments and satisfy performance obligations in order to maintain our rights under these agreements. All of these agreements last either throughout the life of the patents that are the subject ofthe agreements, or with respect to other licensed technology, for a number of years after the first commercial sale of the relevant product. If we fail to comply with the obligationsunder our license agreements or use the intellectual property licensed to us in an unauthorized manner, we may be required to pay damages and our licensors may have the right to terminate the license.If our license agreements are terminated, we may not be able to develop, manufacture, market or sell the products covered by our agreements and those being tested or approved in combination with suchproducts. Such an occurrence could materially adversely affect the value of the product candidate being developed under any such agreement and any other product candidates being developed or tested incombination.

        Inaddition, we are responsible for the cost of filing and prosecuting certain patent applications and maintaining certain issued patents licensed to us. If we do not meet ourobligations under our license agreements in a timely manner, or use the intellectual property licensed to us in an unauthorized manner, we could be required to pay damages and we could lose the rightsto our proprietary technology if our licensor terminated the license. If our license agreements are terminated, we may not be able to develop, manufacture, market or sell the

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productscovered by our agreements and any being tested or approved in combination with such products. Such an occurrence could have a material adverse effect on our business, results of operationsand financial condition.

Intellectual property rights do not necessarily address all potential threats to our competitive advantage.

        The degree of future protection afforded by our intellectual property rights is uncertain because intellectual property rights have limitations,and may not adequately protect our business, or permit us to maintain our competitive advantage. The following examples are illustrative:

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others may be able to make compounds that are similar to our product candidates but that are not covered by the claims of the patents that weown or have exclusively licensed;



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we or our licensors or strategic collaborators might not have been the first to make the inventions covered by the issued patent or pendingpatent application that we own or have exclusively licensed;



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we or our licensors or strategic collaborators might not have been the first to file patent applications covering certain of our inventions;



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others may independently develop similar or alternative technologies or duplicate any of our technologies without infringing our intellectualproperty rights;



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it is possible that our pending patent applications will not lead to issued patents;



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issued patents that we own or have exclusively licensed may not provide us with any competitive advantages, or may be held invalid orunenforceable, as a result of legal challenges by our competitors;



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our competitors might conduct research and development activities in countries where we do not have patent rights and then use the informationlearned from such activities to develop competitive products for sale in our major commercial markets;



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we may not develop additional proprietary technologies that are patentable; and



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the patents of others may have an adverse effect on our business.

        Shouldany of these events occur, they could significantly harm our business, results of operations and prospects.

Patent reform legislation could increase the uncertainties and costs surrounding the prosecution of ourpatent applications and the enforcement or defense of our issued patents.

        Changes in either the patent laws or interpretation of the patent laws in the United States and Ex-US could increase the uncertaintiesand costs. Recent patent reform legislation in the United States and other countries, including the Leahy-Smith America Invents Act, or the Leahy-Smith Act, signed into law in theUnited States on September 16, 2011, could increase those uncertainties and costs surrounding the prosecution of our patent applications and the enforcement or defense of our issuedpatents. The Leahy-Smith Act includes a number of significant changes to U.S. patent law. These include provisions that affect the way patent applications are prosecuted, redefine prior art andprovide more efficient and cost-effective avenues for competitors to challenge the validity of patents. These include allowing third-party

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submissionof prior art to the USPTO during patent prosecution and additional procedures to attack the validity of a patent by USPTO administered post-grant proceedings, including post-grant review,inter partes review, and derivation proceedings. After March 2013, under the Leahy-Smith Act, the United States transitioned to a first inventor to file system in which, assuming that the otherstatutory requirements are met, the first inventor to file a patent application will be entitledto the patent on an invention regardless of whether a third party was the first to invent the claimed invention. However, the Leahy-Smith Act and its implementation could increase the uncertaintiesand costs surrounding the prosecution of our patent applications and the enforcement or defense of our issued patents, all of which could have a material adverse effect on our business, financialcondition, results of operations and prospects.

        TheU.S. Supreme Court has ruled on several patent cases in recent years, either narrowing the scope of patent protection available in certain circumstances or weakening the rights ofpatent owners in certain situations. Depending on future actions by the U.S. Congress, the U.S. courts, the USPTO and the relevant law-making bodies in other countries, the laws and regulationsgoverning patents could change in unpredictable ways that would weaken our ability to obtain new patents or to enforce our existing patents and patents that we might obtain in the future.

We may be subject to litigation with respect to the ownership and use of intellectual property that will becostly to defend or pursue and uncertain in its outcome.

        Our success also will depend, in part, on our refraining from infringing patents or otherwise violating intellectual property owned orcontrolled by others. There is a substantial amount of intellectual property litigation in the biotechnology and pharmaceutical industries, and we may become party to, or threatened with, litigationor other adversarial proceedings regarding intellectual property rights with respect to our products candidates, including interference proceedings before the U.S. Patent and Trademark Office.Pharmaceutical companies, biotechnology companies, universities, research institutions and others may have filed patent applications or have received, or may obtain, issued patents in theUnited States or elsewhere relating to aspects of our technology, and it may not always be clear to industry participants, including us, which patents cover various types of products or methodsof use. The coverage of patents is subject to interpretation by the courts, and the interpretation is not always uniform. Third parties may allege that we have infringed or misappropriated theirintellectual property. If we were sued for patent infringement, we would need to demonstrate that our product candidates, products or methods either do not infringe the patent claims of the relevantpatent or that the patent claims are invalid or unenforceable, and we may not be able to do this. Proving invalidity is difficult. For example, in the United States, proving invalidity requiresa showing of clear and convincing evidence to overcome the presumption of validity enjoyed by issued patents. Even if we are successful in these proceedings, we may incur substantial costs and thetime and attention of our management and scientific personnel could be diverted in pursuing these proceedings, which could have a material adverse effect on us. In addition, we may not have sufficientresources to bring these actions to a successful conclusion.

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        Litigation or other legal proceedings relating to intellectual property claims, with or without merit, is unpredictable and generally expensive and time consumingand, even if resolved in our favor, is likely to divert significant resources from our core business, including distracting our technical and management personnel from their normal responsibilities.In addition, there could be public announcements of the results of hearings, motions or other interim proceedings or developments and if securities analysts or investors perceive these results to benegative, it could have a substantial adverse effect on the market price of our common stock. Such litigation or proceedings could substantially increase our operating losses and reduce the resourcesavailable for development activities or any future sales, marketing or distribution activities. We may not have sufficient financial or other resources to adequately conduct such litigation orproceedings. Some of our competitors may be able to sustain the costs of such litigation or proceedings more effectively than we can because of their greater financial resources and more mature anddeveloped intellectual property portfolios.

        Ifwe are found to infringe a third party's intellectual property rights, we could be forced, including by court order, to cease developing, manufacturing or commercializing theinfringing product candidate or product. Alternatively, we may be required to obtain a license from such third party in order to use the infringing technology and continue developing, manufacturing ormarketing the infringing product candidate. However, we may not be able to obtain any required license on commercially reasonable terms or at all. Even if we were able to obtain a license, it could benon-exclusive, thereby giving our competitors access to the same technologies licensed to us. In addition, we could be found liable for monetary damages, including treble damages and attorneys' feesif we are found to have willfully infringed a patent. A finding of infringement could prevent us from commercializing our product candidates or force us to cease some of our business operations, whichcould materially harm our business. Claims that we have misappropriated the confidential information or trade secrets of third parties could have a similar negative impact on our business.

        Itis uncertain whether the issuance of any third-party patents will require us to alter our products or processes, obtain licenses, if such licenses are available on commerciallyreasonable terms, or cease certain activities completely. Some third-party applications or patents may conflict with our issued patents or pending applications. Any such conflict could result in asignificant reduction of the scope or value of our issued or licensed patents.

        Inaddition, if patents issued to other companies contain blocking, dominating or conflicting claims and such claims are ultimately determined to be valid, we may be required to obtainlicenses to these patents or to develop or obtain alternative non-infringing technology and cease practicing those activities, including potentially manufacturing or selling any products deemed toinfringe those patents. If any licenses are required, there can be no assurance that we will be able to obtain any such licenses on commercially favorable terms, if at all, and if these licenses arenot obtained, we might be prevented from pursuing the development and commercialization of certain of our potential products. Our failure to obtain a license to any technology that we may require tocommercialize our products on favorable terms may have a material adverse impact on our business, financial condition and results of operations.

        Litigation,which could result in substantial costs to us (even if determined in our favor), may also be necessary to enforce any patents issued or licensed to us or to determine thescope and validity of the proprietary rights of others, or to defend against any accusations from third parties

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thatour products or activities are infringing their intellectual property rights. The FDA has only recently published draft guidance documents for implementation of the Biologics Price Competitionand Innovation Act, or BPCIA under the PPACA, related to the development of follow-on biologics (biosimilars), and detailed guidance for patent litigation procedures under this act has not yet beenprovided. If another company files for approval to market a competing follow-on biologic, and/or if such approval is given to such a company, we may be required to promptly initiate patent litigationto prevent the marketing of such biosimilar version of our product prior to the normal expiration of the patent. There can be no assurance that our issued or licensed patents would be held valid by acourt of competent jurisdiction or that any follow-on biologic would be found to infringe our patents.

        Inaddition, if our competitors file or have filed patent applications in the United States that claim technology also claimed by us, we may have to participate in interferenceproceedings to determine priority of invention. These proceedings, if initiated by the USPTO, could result in substantial costs to us, even if the eventual outcome is favorable to us. Such proceedingscan be lengthy, are costly to defend and involve complex questions of law and fact, the outcomes of which are difficult to predict. Moreover, we may have to participate in post-grant proceedings orthird-party ex parte or inter partes reexamination proceedings under the USPTO. An adverse outcome withrespect to a third-party claim or in an interference proceeding could subject us to significant liabilities, require us to license disputed rights from third parties, or require us to cease using suchtechnology, any of which could have a material adverse effect on our business, financial condition and results of operations.

We may become involved in lawsuits to protect or enforce our patents or other intellectual property, whichcould be expensive, time consuming and unsuccessful.

        Competitors may infringe our patents, trademarks, copyrights or other intellectual property. To counter infringement or unauthorized use, we maybe required to file infringement claims, which can be expensive and time consuming and divert the time and attention of our management and scientific personnel. Any claims we assert against perceivedinfringers could provoke these parties to assert counterclaims against us alleging that we infringe their patents, in addition to counterclaims asserting that our patents are invalid or unenforceable,or both. In any patent infringement proceeding, there is a risk that a court will decide that a patent of ours is invalid or unenforceable, in whole or in part, and that we do not have the right tostop the other party from using the invention at issue. There is also a risk that, even if the validity of such patents is upheld, the court will construe the patent's claims narrowly or decide thatwe donot have the right to stop the other party from using the invention at issue on the grounds that our patent claims do not cover the invention. An adverse outcome in a litigation or proceedinginvolving our patents could limit our ability to assert our patents against those parties or other competitors, and may curtail or preclude our ability to exclude third parties from making and sellingsimilar or competitive products. Any of these occurrences could adversely affect our competitive business position, business prospects and financial condition. Similarly, if we assert trademarkinfringement claims, a court may determine that the marks we have asserted are invalid or unenforceable, or that the party against whom we have asserted trademark infringement has superior rights tothe marks in question. In this case, we could ultimately be forced to cease use of such trademarks.

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        Evenif we establish infringement, the court may decide not to grant an injunction against further infringing activity and instead award only monetary damages, which may or may not be anadequate remedy. Furthermore, because of the substantial amount of discovery required in connection with intellectual property litigation, there is a risk that some of our confidential informationcould be compromised by disclosure during litigation. There could also be public announcements of the results of hearings, motions or other interim proceedings or developments. If securities analystsor investors perceive these results to be negative, it could have a material adverse effect on the price of shares of our common stock. Moreover, there can be no assurance that we will have sufficientfinancial or other resources to file and pursue such infringement claims, which typically last for years before they are concluded. Even if we ultimately prevail in such claims, the monetary cost ofsuch litigation and the diversion of the attention of our management and scientific personnel could outweigh any benefit we receive as a result of the proceedings.

We may rely on trade secret and proprietary know-how which can be difficult to trace and enforce and, if weare unable to protect the confidentiality of our trade secrets, our business and competitive position would be harmed.

        We also rely on trade secrets to protect technology, especially where patent protection is not believed to be appropriate or obtainable or wherepatents have not issued. For example, our manufacturing process involves a number of trade secret steps, processes, and conditions. Trade secrets and know-how can be difficult to protect. We attemptto protect our proprietary technology and processes, in part, with confidentiality agreements and assignment ofinvention agreements with our employees and confidentiality agreements with our consultants and certain contractors. Despite these efforts, any of these parties may breach the agreements and discloseour proprietary information, including our trade secrets, and we may not be able to obtain adequate remedies for such breaches. Any disclosure, either intentional or unintentional, by our employees,the employees of third parties with whom we share our facilities or third party consultants and vendors that we engage to perform research, clinical studies or manufacturing activities, ormisappropriation by third parties (such as through a cybersecurity breach) of our trade secrets or proprietary information could enable competitors to duplicate or surpass our technologicalachievements, thus eroding our competitive position in our market.

        Enforcinga claim that a party illegally disclosed or misappropriated a trade secret is difficult, expensive and time-consuming, and the outcome is unpredictable. In addition, somecourts inside and outside the United States are less willing or unwilling to protect trade secrets. If any of our trade secrets were to be lawfully obtained or independently developed by acompetitor or other third party, we would have no right to prevent them from using that technology or information to compete with us. If any of our trade secrets were to be disclosed to orindependently developed by a competitor or other third party, our competitive position would be harmed.

        Therecan be no assurance that these agreements are valid and enforceable, will not be breached, that we would have adequate remedies for any breach, or that our trade secrets will nototherwise become known or be independently discovered by competitors. We may fail in certain circumstances to obtain the necessary confidentiality agreements or assignment of invention agreements, ortheir scope or term may not be sufficiently broad to protect our interests or transfer adequate rights to us.

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        Ifour trade secrets or other intellectual property become known to our competitors, it could result in a material adverse effect on our business, financial condition and results ofoperations. To the extent that we or our consultants or research collaborators use intellectual property owned by others in work for us, disputes may also arise as to the rights to related orresulting know-how and inventions.

The patent protection and patent prosecution for some of our product candidates is dependent or may bedependent in the future on third parties.

        While we normally seek and gain the right to fully prosecute the patents relating to our product candidates, there may be times when platformtechnology patents or product-specific patents that relate to our product candidates are controlled by our licensors. In addition, our licensors and/or licensees may have back-up rights to prosecutepatent applications in the event that we do not do so or choose not to do so, and our licensees may have the right to assume patent prosecution rights after certain milestones are reached. If any ofour licensing collaborators fails to appropriately prosecute and maintain patent protection for patents covering any of our product candidates, our ability to develop and commercialize those productcandidates may be adversely affected and we may not be able to prevent competitors from making, using and selling competing products.

We may not be able to protect our intellectual property rights throughout the world.

        Patents are of national or regional effect, and filing, prosecuting and defending patents on all of our product candidates throughout the worldwould be prohibitively expensive. As such, we may not be able to prevent third parties from practicing our inventions in all countries outside the United States, or from selling or importingproducts made using our inventions in and into the United States or other jurisdictions. Further, the legal systems of certain countries, particularly certain developing countries, do not favorthe enforcement of patents and other intellectual property protection, particularly those relating to pharmaceuticals or biologics, which could make it difficult for us to stop the infringement of ourpatents or marketing of competing products in violation of our proprietary rights generally. In addition, certain developing countries, including China and India, have compulsory licensing laws underwhich a patent owner may be compelled to grant licenses to third parties. In those countries, we and our licensors may have limited remedies if patents are infringed or if we or our licensors arecompelled to grant a license to a third party, which could materially diminish the value of those patents. This could limit our potential revenue opportunities. Accordingly, our efforts to enforce ourintellectual property rights around the world may be inadequate to obtain a significant commercial advantage from the intellectual property that we develop or license.

Patent terms may be inadequate to protect our competitive position on our product candidates for an adequateamount of time.

        Patent rights are of limited duration. Given the amount of time required for the development, testing and regulatory review of new productcandidates, patents protecting such candidates might expire before or shortly after such product candidates are commercialized. Even if patents covering our product candidates are obtained, once thepatent life has expired for a product, we may be open to competition from biosimilar or generic products. A patent term extension based

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onregulatory delay may be available in the U.S. However, only a single patent can be extended for each marketing approval, and any patent can be extended only once, for a single product. Moreover,the scope of protection during the period of the patent term extension does not extend to the full scope of the claim, but instead only to the scope of the product as approved. Laws governinganalogous patent term extensions in foreign jurisdictions vary widely, as do laws governing the ability to obtain multiple patents from a single patent family. Additionally, we may not receive anextension if we fail to apply within applicable deadlines, fail to apply prior to expiration of relevant patents or otherwise fail to satisfy applicable requirements. If we are unable to obtain patentterm extension or restoration, or the term of any such extension is less than we request, the period during which we will have the right to exclusively market our product will be shortened and ourcompetitors may obtain approval of competing products following our patent expiration, and our revenue could be reduced, possibly materially.

We may be subject to claims by third parties asserting that our employees or we have misappropriated theirintellectual property, or claiming ownership of what we regard as our own intellectual property.

        Some of our employees and our licensors' employees, including our senior management, were previously employed at universities or at otherbiotechnology or pharmaceutical companies, including our competitors or potential competitors. Some of these employees may have executed proprietary rights, non-disclosure and non-competitionagreements, or similar agreements, in connection with such previous employment. Although we try to ensure that ouremployees do not use the proprietary information or know-how of others in their work for us, we may be subject to claims that we or these employees have used or disclosed intellectual property,including trade secrets or other proprietary information, of any such third party. Litigation may be necessary to defend against such claims. If we fail in defending any such claims, in addition topaying monetary damages, we may lose valuable intellectual property rights or personnel or sustain damages. Such intellectual property rights could be awarded to a third party, and we could berequired to obtain a license from such third party to commercialize our technology or products. Such a license may not be available on commercially reasonable terms or at all. Even if we aresuccessful in defending against such claims, litigation could result in substantial costs and be a distraction to management.

        Inaddition, while we typically require our employees, consultants and contractors who may be involved in the development of intellectual property to execute agreements assigning suchintellectual property to us, we may be unsuccessful in executing such an agreement with each party who in fact develops intellectual property that we regard as our own, which may result in claims byor against us related to the ownership of such intellectual property. If we fail in prosecuting or defending any such claims, in addition to paying monetary damages, we may lose valuable intellectualproperty rights. Even if we are successful in prosecuting or defending against such claims, litigation could result in substantial costs and be a distraction to our senior management and scientificpersonnel.

Obtaining and maintaining our patent protection depends on compliance with various procedural, documentsubmissions, fee payment and other requirements imposed by governmental patent agencies, and our patent protection could be reduced or eliminated for non-compliance with these requirements.

        Periodic maintenance fees on any issued patent are due to be paid to the USPTO and foreign patent agencies in several stages over the lifetimeof the patent. The USPTO and various foreign

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governmentalpatent agencies require compliance with a number of procedural, documentary, fee payment and other similar provisions during the patent application process. While an inadvertent lapse canin many cases be cured by payment of a late fee or by other means in accordance with the applicable rules, there are situations in which noncompliance can result in abandonment orlapse of the patent or patent application, resulting in partial or complete loss of patent rights in the relevant jurisdiction. Non-compliance events that could result in abandonment or lapse of apatent or patent application include, but are not limited to, failure to respond to official actions within prescribed time limits, non-payment of fees and failure to properly legalize and submitformal documents. If we fail to maintain the patents and patent applications covering our product candidates, our competitive position would be adversely affected.

Risks Related to Owning our Common Stock

Upon completion of the offering we will be subject to the reporting requirements of federal securities laws,which can be expensive and may divert resources from other projects, thus impairing our ability grow.

        Upon completion of the offering we will be subject to reporting and other obligations under the Securities Exchange Act, of 1934, as amended, orthe Exchange Act, including the requirements of Section 404 of the Sarbanes-Oxley Act. Section 404 requires us to conduct an annual management assessment of the effectiveness of ourinternal controls over financial reporting. These reporting and other obligations place significant demands on our financial resources.

        Itmay be time consuming, difficult and costly for us to develop and implement the internal controls and reporting procedures required by the Sarbanes-Oxley Act. We will need to hireadditional financial reporting, internal controls and other finance personnel in order to develop and implement appropriate internal controls and reporting procedures. If we are unable to comply withthe internal controls requirements of the Sarbanes-Oxley Act, then we may not be able to obtain the independent accountant certifications required by such act, which may preclude us from keeping ourfilings with the SEC current and interfere with the ability of investors to trade our securities and for our shares to be listed on any national securities exchange or quoted on the OTCQB.

An active trading market for our common stock may not develop, and you may not be able to sell your commonstock at or above the initial public offering price.

        Prior to the completion of this offering, there has been no public market for our common stock. An active trading market for shares of ourcommon stock may never develop or be sustained following this offering. If an active trading market does not develop, you may have difficulty selling your shares of common stock at an attractiveprice, or at all. The price for our common stock in this offering will be determined by negotiations between us and the underwriters, and it may not be indicative of prices that will prevail in theopen market following this offering. Consequently, you may not be able to sell your common stock at or above the initial public offering price or at any other price or at the time that you would liketo sell. An inactive market may also impair our ability to raise capital by selling our common stock, and it may impair our ability to attract and motivate our employees through equity incentiveawards and our ability to acquire other companies, products or technologies by using our common stock as consideration.

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The price of our common stock may fluctuate substantially.

        You should consider an investment in our common stock to be risky, and you should invest in our common stock only if you can withstand asignificant loss and wide fluctuations in the market value of your investment. Some factors that may cause the market price of our common stock to fluctuate, in addition to the other risks mentionedin this "Risk Factors" section and elsewhere in this prospectus, are:

•

sale of our common stock by our stockholders, executives, and directors;



•

volatility and limitations in trading volumes of our shares of common stock;



•

our ability to obtain financings to conduct and complete research and development activities including, but not limited to, our human clinicaltrials, and other business activities;



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our announcements or our competitors' announcements regarding new products or services, enhancements, significant contracts, acquisitions orstrategic investments;



•

failures to meet external expectations or management guidance;



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clinical trial progress and outcomes;



•

changes in our capital structure or dividend policy;



•

our cash position;



•

announcements and events surrounding financing efforts, including debt and equity securities;



•

our inability to enter into new markets or develop new products;



•

reputational issues;



•

announcements of acquisitions, partnerships, collaborations, joint ventures, new products, capital commitments, or other events by us or ourcompetitors;



•

changes in general economic, political and market conditions in any of the regions in which we conduct our business;



•

changes in industry conditions or perceptions;



•

changes in valuations of similar companies or groups of companies;



•

analyst research reports, recommendation and changes in recommendations, price targets, and withdrawals of coverage;



•

departures and additions of key personnel;



•

disputes and litigations related to contractual obligations;



•

changes in applicable laws, rules, regulations, or accounting practices and other dynamics; or



•

other events or factors, many of which may be out of our control.

        Inaddition, if the market for stocks in our industry or industries related to our industry, or the stock market in general, experiences a loss of investor confidence, the trading priceof our

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commonstock could decline for reasons unrelated to our business, financial condition and results of operations. If any of the foregoing occurs, it could cause our stock price to fall and may exposeus to lawsuits that, even if unsuccessful, could be costly to defend and a distraction to management.

Our management has broad discretion in using the net proceeds from this offering.

        We have stated, in only a general manner, how we intend to use the net proceeds from this offering. See "Use of Proceeds." We cannot, with anyassurance, be more specific at this time. We will have broad discretion in the timing of the expenditures and application of proceeds received in this offering. If we fail to apply the net proceedseffectively, we may not be successful in bringing our proposed products to market. You will not have the opportunity to evaluate all of the economic, financial or other information upon which we maybase our decisions to use the net proceeds from this offering.

Our principal stockholders and management own a significant percentage of our stock and will be able toexercise significant influence over matters subject to stockholder approval.

        As of June 30, 2018, our executive officers, directors and principal security holders, together with their respective affiliates, ownedapproximately 25% of our outstanding securities. Upon completion of the offering (if the underwriters exercise their over-allotment option in full) our executive officers, directors and principalsecurity holders, together with their respective affiliates, will own approximately            % of our outstanding securities. Accordingly, this group of security holders will be able toexert asignificant degree of influence over our management and affairs and over matters requiring security holder approval, including the election of our Board of Directors, future issuances of oursecurities, declaration of dividends and approval of other significant corporate transactions. This concentration of ownership could have the effect of delaying or preventing a change-of-control ofthe Company or otherwise discouraging a potential acquirer from attempting to obtain control of us, which in turn could have a material and adverse effect on the fair market value of our securities.In addition, this significant concentration of share ownership may adversely affect the trading price for our common stock if investors perceive disadvantages in owning stock in a company with suchconcentrated ownership.

Our ability to use our net operating loss carry-forwards and certain other tax attributes is limited bySections 382 and 383 of the Internal Revenue Code.

        Net operating loss carryforwards allow companies to use past year net operating losses to offset against future years' profits, if any, toreduce future tax liabilities. Sections 382 and 383 of the Internal Revenue Code of 1986 limit a corporation's ability to utilize its net operating loss carryforwards and certain other taxattributes (including research credits) to offset any future taxable income or tax if the corporation experiences a cumulative ownership change of more than 50% over any rolling three year period.State net operating loss carryforwards (and certain other tax attributes) may be similarly limited. An ownership change can therefore result in significantly greater tax liabilities than a corporationwould incur in the absence of such a change and any increased liabilities could adversely affect the corporation's business, results of operations, financial condition and cash flow.

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        Evenif an ownership change has not occurred and does not occur as a result of this offering, ownership changes may occur in the future as a result of additional equity offerings orevents over which we will have little or no control, including purchases and sales of our equity by our five percent security holders, the emergence of new five percent security holders, redemptionsof our securities or certain changes in the ownership of any of our five percent security holders.

U.S. federal income tax reform could adversely affect us.

        On December 22, 2017, President Trump signed into law the "Tax Cuts and Jobs Act," or TCJA, that significantly reforms the InternalRevenue Code of 1986, as amended. The TCJA, among other things, includes changes to U.S. federal tax rates, imposes significant additional limitations on the deductibility of interest, allows for theexpensing of capital expenditures, a reduction to the maximum deduction allowed for net operating losses generated in tax years after December 31, 2017, and puts into effect the migration froma "worldwide" system of taxation to a partially territorial system. We do not expect tax reform to have a material impact to our projection of minimal cash taxes or to our net operating losses. Ournet deferred tax assetsand liabilities will be revalued at the newly enacted U.S. corporate rate, and the impact will be recognized in our tax expense in the year of enactment. Further, any eligibility we may have or maysomeday have for tax credits associated with the qualified clinical testing expenses arising out of the development of orphan drugs will be reduced to 25% as a result of the TCJA; thus, our nettaxable income may be affected. We continue to examine the impact this tax reform legislation may have on our business. The impact of this tax reform on holders of our common stock is uncertain andcould be adverse. This prospectus does not discuss any such tax legislation or the manner in which it might affect purchasers of our common stock. We urge our stockholders, including purchasers ofcommon stock in this offering, to consult with their legal and tax advisors with respect to such legislation and the potential tax consequences of investing in our common stock.

You will incur immediate dilution as a result of this offering.

        If you purchase common stock in this offering, you will pay more for your shares than the net tangible book value of your shares. As a result,you will incur immediate dilution of $            per share, representing the difference between the assumed initial public offering price of$            per share (the midpoint of the rangeon the cover of this prospectus) and our estimated net tangible book value per share as of December 31, 2017 of $            . Accordingly, should we be liquidated at our book value,youwould not receive the full amount of your investment.

Future sales and issuances of our common stock or rights to purchase common stock pursuant to our equityincentive plan could result in additional dilution of the percentage ownership of our stockholders and could cause our share price to fall.

        We expect that significant additional capital will be needed in the future to continue our planned operations, including expanding research anddevelopment, funding clinical trials, purchasing of capital equipment, hiring new personnel, commercializing our products, and continuing activities as an operating public company. To the extent weraise additional capital by issuing equity securities, our stockholders may experience substantial dilution. We may sell common stock, convertible securities or other equity securities in one or moretransactions at

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pricesand in a manner we determine from time to time. If we sell common stock, convertible securities or other equity securities in more than one transaction, investors may be materially diluted bysubsequent sales. Such sales may also result in material dilution to our existing stockholders, and new investors could gain rights superior to our existing stockholders.

We do not intend to pay cash dividends on our shares of common stock so any returns will be limited to thevalue of our shares.

        We currently anticipate that we will retain future earnings for the development, operation and expansion of our business and do not anticipatedeclaring or paying any cash dividends for the foreseeable future. Any return to stockholders will therefore be limited to the increase, if any, of our share price.

We are an "emerging growth company" and will be able to avail ourselves of reduced disclosure requirementsapplicable to emerging growth companies, which could make our common stock less attractive to investors.

        We are an "emerging growth company," as defined in the Jumpstart Our Business Startups Act of 2012, or the JOBS Act, and we intend to takeadvantage of certain exemptions from various reporting requirements that are applicable to other public companies that are not "emerging growth companies" including not being required to comply withthe auditor attestation requirements of Section 404(b) of the Sarbanes-Oxley Act, reduced disclosure obligations regarding executive compensation in our periodic reports and proxy statements,and exemptions from the requirements of holding a nonbinding advisory vote on executive compensation and stockholder approval of any golden parachute payments not previously approved. In addition,Section 107 of the JOBS Act also provides that an "emerging growth company" can take advantage of the extended transition period provided in Section 7(a)(2)(B) of the Securities Act, forcomplying with new or revised accounting standards. In other words, an "emerging growth company" can delay the adoption of certain accounting standards until those standards would otherwise apply toprivate companies. We are electing to delay such adoption of new or revised accounting standards, and as a result, we may not comply with new or revised accounting standards on the relevant dates onwhich adoption of such standards is required fornon-emerging growth companies. As a result of such election, our financial statements may not be comparable to the financial statements of other public companies. We cannot predict if investors willfind our common stock less attractive because we may rely on these exemptions. If some investors find our common stock less attractive as a result, there may be a less active trading market for ourcommon stock and our stock price may be more volatile. We may take advantage of these reporting exemptions until we are no longer an "emerging growth company." We will remain an "emerging growthcompany" until the earliest of (i) the last day of the fiscal year in which we have total annual gross revenues of $1.07 billion or more; (ii) the last day of our fiscal yearfollowing the fifth anniversary of the date of the completion of this offering; (iii) the date on which we have issued more than $1 billion in nonconvertible debt during the previousthree years; or (iv) the date on which we are deemed to be a large accelerated filer under the rules of the Securities and Exchange Commission.

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Because we have elected to defer compliance with new or revised accounting standards, our financial statementdisclosure may not be comparable to similar companies.

        We have elected to use the extended transition period for complying with new or revised accounting standards under Section 102(b)(1) ofthe JOBS Act. This allows us to delay the adoption of new or revised accounting standards that have different effective dates for public and private companies until those standards apply to privatecompanies. As a result of our election, our financial statements may not be comparable to companies that comply with public company effective dates.

        Becauseof this extended transition period, we may be less attractive to investors and it may be difficult for us to raise additional capital as and when we need it. Investors may beunable to compare our business with other companies in our industry if they believe that our financial accounting is not as transparent as other companies in our industry. If we are unable to raiseadditional capital as and when we need it, our financial condition and results of operations may be materially and adversely affected.

We may be at risk of securities class action litigation.

        We may be at risk of securities class action litigation. This risk is especially relevant for us due to our dependence on positive clinicaltrial outcomes and regulatory approvals of each of our product candidates. In the past, biotechnology and pharmaceutical companies have experienced significant stock price volatility, particularlywhen associated with binary events such as clinical trials and product approvals. If we face such litigation, it could result in substantial costs and a diversion of management's attention andresources, which could harm our business and results in a decline in the market price of our common stock.

Our management will be required to devote substantial time to compliance initiatives.

        As a public company, we will incur significant legal, accounting and other expenses that we did not incur as a newly formed entity. TheSarbanes-Oxley Act, as well as rules subsequently implemented by the SEC and The Nasdaq Capital Market, have imposed various new requirements on public companies, including requiring establishment andmaintenance of effective disclosure and financial controls and changes in corporate governance practices. Our management and other personnel will need to devote a substantial amount of time to thesenew compliance initiatives. Moreover, these rules and regulations will increase our legal and financial compliance costs and will make some activities more time consuming and costly. We expect theserules and regulations to make it more difficult and more expensive for us to obtain director and officer liability insurance and we may be required to incur substantial costs to maintain the same orsimilar coverage.

There is no guarantee that our common stock will be listed on The Nasdaq Capital Market.

        We have applied to have our shares of common stock listed on The Nasdaq Capital Market. Upon completion of this offering, we believe that wewill satisfy the listing requirements and expect that our common stock will be listed on The Nasdaq Capital Market. Such listing, however, is not guaranteed. If the application is not approved, wewill seek to have our common stock quoted on the OTCQB. Even if such listing is approved, there can be no assurance any broker will

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beinterested in trading our common stock. Therefore, it may be difficult to sell any shares you purchase in this offering if you desire or need to sell them. Neither we nor the underwriters canprovide any assurance that an active and liquid trading market in our common stock will develop or, if developed, that the market will continue.

Even if we are successful in listing our common stock on The Nasdaq Capital Market, our common stock may bedelisted if we fail to comply with continued listing standards.

        If we fail to meet any of the continued listing standards of The Nasdaq Capital Market, our common stock could be delisted from The NasdaqCapital Market. These continued listing standards include specifically enumerated criteria, such as:

•

a $1.00 minimum closing bid price;



•

stockholders' equity of $2.5 million;



•

500,000 shares of publicly-held common stock with a market value of at least $1 million;



•

300 round-lot stockholders; and



•

compliance with Nasdaq's corporate governance requirements, as well as additional or more stringent criteria that may be applied in theexercise of Nasdaq's discretionary authority.

        Ifwe fail to comply with Nasdaq's continued listing standards, we may be delisted and our common stock will trade, if at all, only on the over-the-counter market, such as the OTCBulletin Board or OTCQX market, and then only if one or more registered broker-dealer market makers comply with quotation requirements. In addition, delisting of our common stock could depress ourstock price, substantially limit liquidity of our common stock and materially adversely affect our ability to raise capital on terms acceptable to us, or at all. Finally, delisting of our common stockcould result in our common stock becoming a "penny stock" under the Exchange Act.

Upon our dissolution, you may not recoup all or any portion of your investment.

        In the event of a liquidation, dissolution or winding-up of us, whether voluntary or involuntary, the proceeds and/or our assets may not besufficient to repay the aggregate initial public offering price you paid for shares purchased in this offering. In this event, you could lose some or all of your investment.

We have identified certain material weaknesses in our internal control over financial reporting. Failure tomaintain effective internal controls could cause our investors to lose confidence in us and adversely affect the market price of our common stock. If our internal controls are not effective, we maynot be able to accurately report our financial results or prevent fraud.

        Effective internal control over financial reporting is necessary for us to provide reliable financial reports in a timely manner. In connectionwith the preparation of our financial statements for the year ended December 31, 2017 and 2016, we concluded that there were material weaknesses in our internal control over financialreporting. A material weakness is a significant deficiency, or a combination of significant deficiencies, in internal control over financial reporting such that it is reasonably possible that amaterial misstatement of the annual or interim

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financialstatements will not be prevented or detected on a timely basis. We have identified certain material weaknesses in our internal controls resultingfrom:

•

one individual having almost complete responsibility for the processing of financial information; and



•

our finance department not having adequate staff to process in a timely manner complex, non-routine transactions.

        Whilewe have designed and implemented, or expect to implement, measures that we believe address or will address these control weaknesses, we continue to develop our internal controls,processes and reporting systems by, among other things, hiring qualified personnel with expertise to perform specific functions, implementing software systems to manage our revenue and expenses and toallow us to budget, undertaking multi-year financial planning and analyses and designing and implementing improved processes and internal controls, including ongoing senior management review and auditcommittee oversight. Upon completion of this offering we plan to begin measures to remediate the identified material weakness by hiring financial consultants and expect to hire additional senioraccounting staff to complete the remediation by the end of 2018. We expect to incur additional costs to remediate these weaknesses, primarily personnel costs and external consulting fees. We may notbe successful in implementing these systems or in developing other internal controls, which may undermine our ability to provide accurate, timely and reliable reports on our financial and operatingresults. Further, we will not be able to fully assess whether the steps we are taking will remediate the material weaknesses in our internal control over financial reporting until we have completedour implementation efforts and sufficient time passes in order to evaluate their effectiveness. In addition, if we identify additional material weaknesses in our internal control over financialreporting, we may not detect errors on a timely basis and our financial statements may be materially misstated. Moreover, in the future we may engage in business transactions, such as acquisitions,reorganizations or implementation of new information systems that could negatively affect our internal control over financial reporting and result in material weaknesses.

        Ourmanagement and independent registered public accounting firm did not perform an evaluation of our internal control over financial reporting during any period in accordance with theprovisions of the Sarbanes-Oxley Act. Had we and our independent registered public accounting firm performed an evaluation of our internal control over financial reporting in accordance with theprovisions of the Sarbanes-Oxley Act, additional control deficiencies amounting to material weaknesses may have been identified. If we identify new material weaknesses in our internal control overfinancial reporting, if we are unable to comply with the requirements of Section 404 of the Sarbanes-Oxley Act in a timely manner, if we are unable to assert that our internal control overfinancial reporting is effective, or if our independent registered public accounting firm is unable to express an opinion as to the effectiveness of our internal control over financial reporting, wemay be late with the filing of our periodic reports, investors may lose confidence in the accuracy and completeness of our financial reports and the market price of our common stock could benegatively affected. As a result of such failures, we could also become subject to investigations by the stock exchange on which our securities are listed, the SEC, or other regulatory authorities,and become subject to litigation from investors and stockholders, which could harm our reputation, financial condition or divert financial and management resources from our core business.

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Financial reporting obligations of being a public company in the United States are expensive andtime-consuming, and our management will be required to devote substantial time to compliance matters.

        As a publicly traded company we will incur significant additional legal, accounting and other expenses that we did not incur as a privatelyheld, company. The obligations of being a public company in the United States require significant expenditures and will place significant demands on our management and other personnel,including costs resulting from public company reporting obligations under the Securities Exchange Act of 1934, as amended, or the Exchange Act, and the rules and regulations regarding corporategovernance practices, including those under the Sarbanes-Oxley Act of 2002, or the Sarbanes-Oxley Act, the Dodd-Frank Wall Street Reform and Consumer Protection Act, or the Dodd-Frank Act, and thelisting requirements of the stock exchange on which our securities are listed. These rules require the establishment and maintenance of effective disclosure and financial controls and procedures,internal control over financial reporting and changes in corporate governance practices, among many other complex rules that are often difficult to implement, monitor and maintain compliance with.Moreover, despite recent reforms made possible by the JOBS Act, the reporting requirements, rules, and regulations will make some activities more time-consuming and costly, particularly after we arenolonger an "emerging growth company." In addition, we expect these rules and regulations to make it more difficult and more expensive for us to obtain director and officer liability insurance. Ourmanagement and other personnel will need to devote a substantial amount of time to ensure that we comply with all of these requirements and to keep pace with new regulations, otherwise we may fall outof compliance and risk becoming subject to litigation or being delisted, among other potential problems.

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CAUTIONARY NOTE CONCERNING FORWARD-LOOKING STATEMENTS

        This prospectus contains forward-looking statements that involve risks and uncertainties. You should not place undue reliance onthese forward-looking statements. Our actual results could differ materially from those anticipated in the forward-looking statements for many reasons, including the reasons described in our"Prospectus Summary," "Use of Proceeds," "Risk Factors," "Management Discussion and Analysis of Financial Condition and Result of Operations," and "Business" sections. In some cases, you can identifythese forward-looking statements by terms such as "anticipate," "believe," "continue," "could," "depends," "estimate," "expects," "intend," "may," "ongoing," "plan," "potential," "predict," "project,""should," "will,""would" or the negative of those terms or other similar expressions, although not all forward-looking statements contain those words.

        Ouroperations and business prospects are always subject to risks and uncertainties including, among others:

•

the timing of regulatory submissions;



•

our ability to obtain and maintain regulatory approval of our existing product candidates and any other product candidates we may develop, andthe labeling under any approval we may obtain;



•

approvals for clinical trials may be delayed or withheld by regulatory agencies;



•

preclinical and clinical studies will not be successful or confirm earlier results or meet expectations or meet regulatory requirements or meetperformance thresholds for commercial success;



•

risks relating to the timing and costs of clinical trials, the timing and costs of other expenses;



•

risks associated with obtaining funding from third parties;



•

management and employee operations and execution risks;



•

loss of key personnel;



•

competition;



•

risks related to market acceptance of products;



•

intellectual property risks;



•

assumptions regarding the size of the available market, benefits of our products, product pricing, timing of product launches;



•

risks associated with the uncertainty of future financial results;



•

risks associated with this offering;



•

our ability to attract collaborators and partners; and



•

risks associated with our reliance on third party organizations.

        Theforward-looking statements in this prospectus represent our views as of the date of this prospectus. We anticipate that subsequent events and developments will cause our views tochange. However, while we may elect to update these forward-looking statements at some point in the future, we have no current intention of doing so except to the extent required by applicable law.You should, therefore, not rely on these forward-looking statements as representing our views as of any date subsequent to the date of this prospectus.

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INDUSTRY AND MARKET DATA

        This prospectus contains estimates and other statistical data made by independent parties and by us relating to market size andgrowth and other data about our industry. We obtained the industry and market data in this prospectus from our own research as well as from industry and general publications, surveys and studiesconducted by third parties. This data involves a number of assumptions and limitations and contains projections and estimates of the future performance of the industries in which we operate that aresubject to a high degree of uncertainty. We caution you not to give undue weight to such projections, assumptions andestimates. Further, industry and general publications, studies and surveys generally state that they have been obtained from sources believed to be reliable, although they do not guarantee theaccuracy or completeness of such information. In addition, while we believe that the results and estimates from our internal research are reliable, such results and estimates have not been verified byany independent source.

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USE OF PROCEEDS

        We estimate that the net proceeds from our issuance and sale of            shares of our common stock in this offering willbe approximately $             million, assuming an initial public offering price of $            per share, which is themidpoint of the range listed on the cover page of thisprospectus, after deducting estimated underwriting discounts and commissions and estimated offering expenses payable by us. If the underwriters exercise their over-allotment option in full, weestimate that the net proceeds from this offering will be approximately $             million.

        Weintend to use the net proceeds to fund our planned clinical trials, manufacturing and process development, analytical testing, regulatory expenses and for general corporate purposes,including working capital. We intend to use the net proceeds from this offering as follows:

•

Approximately $            for the planned Phase 3 pivotal trial evaluating AR-301 for the treatment of HAP and VAP associated with S. aureus infection.



•

Approximately $            for the ongoing Phase 2 trial evaluating AR-105 for the treatment of HAP and VAPassociated with P. aeruginosa infection.



•

Approximately $            for the manufacturing of clinical supplies of AR-101 for use in the planned Phase 2/3pivotal trial evaluatingAR-101 for the treatment of HAP and VAP associated with P. aeruginosa infection.



•

Approximately $            for the manufacturing of clinical supplies of AR-105 for use in the planned Phase 3clinical trial.



•

The remainder for general corporate purposes, including working capital and regulatory expenses.

        Weexpect that the application of the proceeds to each of the activities as described above will be sufficient to complete such activities, but there can be no guarantee that we will notrequire additional funds to complete the activities or that, even if we do receive additional funds, that we will be able to complete the trials at all. Please see "Risk Factors —Risks Relating to Clinical Development and Commercialization of Our Product Candidates."

        Inthe ordinary course of our business, we expect to from time to time evaluate the acquisition of, investment in or in-license of complementary products, technologies or businesses, andwe could use a portion of the net proceeds from this offering for such activities. We currently do not have any agreements, arrangements or commitments with respect to any potential acquisition,investment or license.

        Thisexpected use of net proceeds from this offering represents our intentions based upon our current plans and business conditions. The amounts and timing of our actual expenditures mayvary significantly depending on numerous factors, including the status of and results from clinical trials of our product candidates. As a result, our management will retain broad discretion over theallocation of the net proceeds from this offering. We may find it necessary or advisable to use thenet proceeds from this offering for other purposes, and we will have broad discretion in the application of net proceeds from this offering. Furthermore, we anticipate that we will need to secureadditional funding for the further development of our product candidates or commercially launch our product candidates in the United States.

        Pendingour use of the net proceeds from this offering, we intend to invest the net proceeds in a variety of capital preservation investments, including short-term, investment-grade,interest-bearing instruments and U.S. government securities.

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DIVIDEND POLICY

        We have never paid or declared any cash dividends on our common stock, and we do not anticipate paying any cash dividends on ourcommon stock in the foreseeable future. We intend to retain all available funds and any future earnings to fund the development and expansion of our business. Any future determination to pay dividendswill be at the discretion of our board of directors and will depend upon a number of factors, including our results of operations, financial condition, future prospects, contractual restrictions,restrictions imposed by applicable law and other factors our board of directors deems relevant.

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CAPITALIZATION

        The following table sets forth our cash and cash equivalents and capitalization as of March 31,2018:

•

on an actual basis;



•

on a pro forma basis to give effect to (i) the automatic conversion of all outstanding shares of our Series A convertiblepreferred stock into an aggregate of 36,196,193 shares of our common stock and (ii) the automatic conversion of all outstanding preferred stock warrants into warrants to purchase8,725,289 shares of our common stock, including the resultant reclassification of our preferred stock warrant liability to additional paid-in capital, a component of total stockholders' equityin connection with such conversion, upon the closing of this offering; and



•

on a pro forma, as adjusted basis to give effect to (i) the pro forma adjustments set forth above and (ii) the issuance and saleof            shares of common stock in this offering assuming an initial offering public offering price of $            per share(the midpoint of the range set forth on the cover page ofthis prospectus), after deducting the estimated underwriting discounts and commissions and our estimated offering expenses.

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        Thenumber of shares of our common stock that will be outstanding after this offering is based on 37,263,883 shares of our common stock outstanding as of June 30, 2018, andexcludes:

•

4,942,873 shares of our common stock issuable upon the exercise of options to purchase shares of our common stock outstanding as ofJune 30, 2018, with a weighted-average exercise price of $1.82 per share;



•

3,897,482 shares of our common stock issuable upon the exercise of warrants to purchase common stock outstanding as of June 30, 2018,with a weighted-average exercise price of $2.73 per share;



•

8,725,289 shares of our common stock issuable upon the exercise of warrants to purchase Series A convertible preferred stock outstandingas of June 30, 2018 with a weighted average exercise price of $2.26 per share; and



•

359,445 shares of our common stock reserved for future issuance under our 2014 Equity Incentive Plan, or the 2014 Plan.

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DILUTION

        If you invest in our common stock, your ownership interest will be diluted to the extent of the difference between the initialpublic offering price per share of our common stock and the pro forma as adjusted net tangible book value per share of our common stock immediately after this offering. Dilution results from the factthat the initial public offering price per share is substantially in excess of the book value per share attributable to the existing stockholders for the presently outstanding stock. As ofMarch 31, 2018, our pro forma net tangiblebook value was $15,694,000, or $0.42 per share of common stock. Pro forma net tangible book value per share represents the amount of our total tangible assets less total liabilities, divided by37,263,883, the number of shares of common stock outstanding at March 31, 2018, after giving effect to (i) the automatic conversion of all outstanding shares of our Series Aconvertible preferred stock into an aggregate 36,196,193 shares of common stock and (ii) the automatic conversion of all outstanding preferred stock warrants into warrants to purchase8,725,289 shares of our common stock, including the resultant reclassification of our preferred stock warrant liability to additional paid-in capital, a component of total stockholders' equityin connection with such conversion, upon the closing of this offering

        Aftergiving effect to the pro forma adjustments set forth above and the sale of shares of our common stock in this offering, assuming an initial public offering price of$            per share, the mid-point of the price range set forth on the cover page of this prospectus, after deducting estimated underwriting discounts and commissions and estimatedofferingexpenses payable by us, our pro forma, as adjusted net tangible book value as of December 31, 2017 would have been $             million, or$            per share. This amountrepresents an immediate increase in pro forma, as adjusted net tangible book value of $            per share to our existing stockholders and an immediate dilution in pro forma, as adjustednettangible book value of approximately $            per share to new investors purchasing shares of our common stock in this offering. We determine dilution by subtracting the pro forma, asadjustednet tangible book value per share after the offering from the amount of cash that a new investor paid for a share of common stock.

        Thefollowing table illustrates this dilution on a per share basis:

        Ifthe underwriters exercise their option to purchase additional shares in full, the pro forma, as adjusted net tangible book value per share after giving effect to the offering would be$            per share. This represents an increase in pro forma, as adjusted net tangible book value of $            per share toexisting stockholders and dilution in pro forma, as adjustednet tangible book value of $            per share to new investors.

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        A$1.00 increase (decrease) in the assumed initial public offering price of $            , the midpoint of the range set forth on the cover page of this prospectus, would increase(decrease) our pro forma, as adjusted net tangible book value after this offering by $             million and the pro forma, as adjusted net tangible book value per share after thisoffering by $            per share and would increase (decrease) the dilution per share to new investors in this offering by$            per share, assuming the number of shares offered byus, as set forth on the cover page of this prospectus, remains the same, and after deducting estimated underwriting discounts and commissions. Similarly, each increase (decrease) of 1.0 millionshares in the number of shares of common stock offered by us would increase (decrease) the dilution per share to new investors in this offering by $            per share, assuming no changein theassumed initial public offering price, as set forth on the cover page of this prospectus, and after deducting estimated underwriting discounts and commissions. The information discussed above isillustrative only and may change based on the actual initial public offering price and other terms of the offering determined at pricing.

        Thefollowing table summarizes, on the pro forma as adjusted basis described above, the total number of shares of common stock purchased from us, the total consideration paid or to bepaid, and the average price per share paid or to be paid by existing shareholders and by new investors in this offering at an assumed initial public offering price of $            per share,whichis the midpoint of the range set forth on the cover page of this prospectus, before deducting estimated underwriting discounts and commissions and estimated offering expenses payable by us:

        A$1.00 increase (decrease) in the assumed initial public offering price of $            per share, which is the midpoint of the range set forth on the cover page of this prospectus,would increase (decrease)the total consideration paid by investors participating in this offering, total consideration paid by all stockholders and the average price per share paid by all stockholders by approximately$             million, $             million and$            million, respectively, assuming that the number of shares offered by us, as set forth on the cover page of thisprospectus, remains the same. Similarly, each increase (decrease) of 1.0 million shares in the number of shares of common stock offered by us would increase (decrease) the total considerationpaid by investors participating in this offering, total consideration paid by all stockholders and the average price per share paid by all stockholders by approximately $            million,$            million and $            million, respectively, assuming no change in the assumed initial public offering price.

        Thetable above assumes no exercise of the underwriters' over-allotment option in this offering. If the underwriters' over-allotment option is exercised in full, the number of commonshares held by new investors purchasing common stock in this offering would be increased to        % of the total number of shares of common stock outstanding after this offering, and thenumber of shares held by existing shareholders would be reduced to        % of the total number of shares of common stock outstanding after this offering.

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        Tothe extent that stock options or warrants are exercised, new stock options are issued under our equity incentive plan, or we issue additional common stock in the future, there will befurther dilution to investors participating in this offering. In addition, we may choose to raise additional capital because of market conditions or strategic considerations, even if we believe thatwe have sufficient funds for our current or future operating plans. If we raise additional capital through the sale of equity or convertible debt securities, the issuance of these securities couldresult in further dilution to our shareholders.

        Thenumber of shares of our common stock that will be outstanding after this offering is based on 37,263,883 shares of our common stock outstanding as of June 30, 2018, andexcludes:

•

4,942,873 shares of our common stock issuable upon the exercise of options to purchase shares of our common stock outstanding as ofJune 30, 2018, with a weighted-average exercise price of $1.82 per share;



•

3,897,482 shares of our common stock issuable upon the exercise of warrants to purchase common stock outstanding as of June 30, 2018,with a weighted-average exercise price of $2.73 per share;



•

8,725,289 shares of our common stock issuable upon the exercise of warrants to purchase Series A convertible preferred stock outstandingas of June 30, 2018 with a weighted average exercise price of $2.26 per share; and



•

359,445 shares of our common stock reserved for future issuance under our 2014 Equity Incentive Plan, or the 2014 Plan.

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SELECTED CONSOLIDATED FINANCIAL DATA

        The following table summarizes our selected consolidated financial data for the periods and as of thedates indicated. Our selected consolidated statements of operations data for each of the periods ended December 31, 2017 and 2016, and our selected consolidated balance sheet data as ofDecember 31, 2017 and 2016, have been derived from our audited financial statements and their related notes, which are included elsewhere in this prospectus. The unaudited selected consolidatedstatements of operations data for the three months ended March 31, 2018 and 2017, and the unaudited consolidated balance sheet data as of March 31, 2018, are derived from our unauditedconsolidated financial statements, which are included elsewhere in this prospectus. Our unaudited consolidated financial statements have been prepared on the same basis as the audited consolidatedfinancialstatements and, in the opinion of management, include all adjustments, consisting of normal recurring adjustments necessary for a fair presentation of our financial condition as of such dates and ourresults of operations for such periods. Our historical results are not necessarily indicative of the results to be expected for any future periods and our interim results are not necessarilyindicative of the results to be expected for the full fiscal year. Our selected consolidated financial data should be read together with the section entitled "Management's Discussion and Analysis ofFinancial Condition and Results of Operations" and with our consolidated financial statements and their related notes, which are included elsewhere in this prospectus.

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Consolidated Statements of Operations Data
(In thousands, except share and per share data)

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Consolidated Balance Sheet Data
(In thousands)

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MANAGEMENT'S DISCUSSION AND ANALYSIS OF
FINANCIAL CONDITION AND RESULTS OF OPERATIONS

        The following discussion and analysis should be read in conjunction with "Selected ConsolidatedFinancial Data" and our financial statements and related notes included elsewhere in this prospectus. This discussion and analysis and other parts of this prospectus contain forward-looking statementsbased upon current beliefs, plans and expectations that involve risks, uncertainties and assumptions, such as statements regarding our plans, objectives, expectations, intentions and projections. Ouractual results and the timing of selected events could differ materially from those anticipated in these forward-looking statements as a result of several factors, including those set forth under"Risk Factors" and elsewhere in this prospectus. You should carefully read the "Risk Factors" section of this prospectus to gain an understanding of the important factors that could cause actualresults to differ materially from our forward-looking statements. Please also see the section entitled "Cautionary Note Concerning Forward-Looking Statements."

Overview

        We are a late-stage biopharmaceutical company focused on the discovery and development of targeted immunotherapy using fully human monoclonalantibodies, or mAbs, to treat life-threatening infections. mAbs represent an innovative treatment approach that harnesses the human immune system to fight infections and are designed to overcome thedeficiencies associated with current therapies, such as rise in drug resistance, short duration of response, negative impact on the human microbiome, and lack of differentiation among the treatmentalternatives. The majority of our product candidates are derived by employing our differentiated antibody discovery platform called MabIgX. Our proprietary product pipeline is comprised of fully humanmAbs targeting specific pathogens associated with life-threatening bacterial infections, primarily hospital-acquired pneumonia, or HAP, and ventilator-associated pneumonia, or VAP. Two of our productcandidates have exhibited promising preclinical data and clinical data are available from two completed studies. Our lead product candidate, AR-301, also referred to as Salvecin, targets the alphatoxin produced by gram-positive bacteria Staphylococcus aureus, or S. aureus, a common pathogenassociated with HAP and VAP. We have conducted an end-of-Phase 2 meetingwith the US Food and Drug Administration, or FDA, and expect to initiate a Phase 3 pivotal trial for AR-301 in the second half of 2018.

        Todate, we have devoted substantially all of our resources to research and development efforts relating to our therapeutic candidates, including conducting clinical trials anddeveloping manufacturing capabilities, in-licensing related intellectual property, protecting our intellectual property and providing general and administrative support for these operations. We havegenerated revenue from our payments under our collaboration strategic research and development contracts and federal awards and grants, as well as awards and grants from not-for-profit entities andfee for service to third party entities. Since our inception, we have funded our operations primarily through these sources and the issuance of convertible preferred stock and debt securities.

        Wehave incurred losses in most years since our inception. Our net losses were approximately $24.7 million for the year ended December 31, 2017 and $8.4 million forthe year ended December 31, 2016 and $7.3 million for the three months ended March 31, 2018. As of March 31, 2018, we had an accumulated deficit of approximately$55.8 million. As of March 31, 2018, we had

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$20.4million of cash and cash equivalents. Substantially all our net losses have resulted from costs incurred in connection with our research and development programs, clinical trials, intellectualproperty matters, building our manufacturing capabilities, and from general and administrative costs associated with our operations.

        Wehave not yet achieved commercialization of our products and have a cumulative net loss from our operations. We will continue to incur net losses for the foreseeable future. Ourconsolidated financial statements have been prepared assuming that we will continue as a going concern. We will require additional capital to meet our long-term operating requirements. We expect toraise additional capital through the sale of equity and/or debt securities. Historically, our principal sources of cash have included proceeds from grant funding, fees for services performed, issuanesof convertible debt and the sale of our preferred stock. We principal uses of cash have included cash used in operations. We expect that the principal uses of cash in the future will be for continuingoperations, funding of research and development including our clinical trials and general working capital requirements.

        Weanticipate that our expenses will increase substantially if and as we:

•

continue enrollment in our ongoing clinical trials;



•

initiate new clinical trials;



•

seek to identify, assess, acquire and develop other products, therapeutic candidates and technologies;



•

seek regulatory and marketing approvals in multiple jurisdictions for our therapeutic candidates that successfully complete clinical studies;



•

establish collaborations with third parties for the development and commercialization of our products and therapeutic candidates;



•

make milestone or other payments under our agreements pursuant to which we have licensed or acquired rights to intellectual property andtechnology;



•

seek to maintain, protect, and expand our intellectual property portfolio;



•

seek to attract and retain skilled personnel;



•

incur the administrative costs associated with being a public company and related costs of compliance;



•

create additional infrastructure to support our operations as a commercial stage public company and our planned future commercializationefforts; and



•

experience any delays or encounter issues with any of the above.

        Weexpect to continue to incur significant expenses and increasing losses for at least the next several years. Accordingly, we anticipate that we will need to raise additional capital inaddition to the net proceeds from this offering in order to obtain regulatory approval for, and the commercialization of our therapeutic candidates. Until such time that we can generate meaningfulrevenue from product sales, if ever, we expect to finance our operating activities through public or private equity or debt financings, government or other third-party funding and othercollaborations, strategic alliances and licensing arrangements or a combination of these

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approaches.If we are unable to obtain funding on a timely basis, we may be required to significantly curtail, delay or discontinue one or more of our research or development programs or thecommercialization of any approved therapies or products or be unable to expand our operations or otherwise capitalize on our business opportunities, as desired, which could materially adversely affectour business, financial condition and results of operations.

Financial Overview

Revenue

        Our sources of revenue are grants and contract services provided to third party entities related to research and development activities underspecific agreements with such granting authorities and third parties. As there is a contractually agreed upon price, and collectability from the granting authorities or other entities is reasonablyassured, revenue for these services are earned according to the terms of the respective agreements, usually as progress is made throughout the term of the agreement or as certain material milestonesare met.

        Inaddition, we have an award agreement with the Cystic Fibrosis Foundation to support funding for the development of our Inhaled Gallium Citrate Anti-Infective program. In addition, wehave a collaborative and option agreement with GlaxoSmithKline Biologicals S.A., or GSK, aimed at evaluating improved formulations for a rotavirus vaccine. These agreements contain upfrontpayments. We recognize revenue from upfront payments ratably over the term of our estimated period of performance under the agreements or as certain milestones are met. In addition to receivingupfront payments, we may also be entitled to milestone and other contingent payments upon achieving predefined objectives or the exercise of options for specified programs by our strategic partners.Such payments are recorded as revenue when we achieve the underlying milestone if there is substantive uncertainty at the date the arrangement is entered into that the event will be achieved. For theyear ended December 31, 2017, we recognized approximately$89,000 in revenue pursuant to our Cystic Fibrosis Foundation agreement and we recognized approximately $771,000 in revenue pursuant to our GSK agreement. For the three months ended March 31,2018, we recognized approximately $322,000 in revenue pursuant to our Cystic Fibrosis Foundation agreement and no revenue pursuant to our GSK agreement. No revenue was recognized on either agreementprior to 2017.

        Weexpect that any revenue we generate for the foreseeable future will fluctuate from period to period as a result of the timing and amount of milestones and other payments from ouragreements.

Cost of Contract Revenue

        Cost of contract revenue includes the costs of research and development personnel, lab supplies, outside research expenses and facility costsand other indirect and overhead costs associated with contract services for third party entities.

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Research and Development Expenses

        We recognize research and development expenses as they are incurred. Our research and development expenses consist primarilyof:

•

salaries and related overhead expenses, which include stock-based compensation and benefits for personnel in research and developmentfunctions;



•

fees paid to consultants and contract research organizations, or CROs, including in connection with our preclinical studies and clinical trialsand other related clinical trial fees, such as for investigator grants, patient screening, laboratory work, clinical trial material management and statistical compilation and analyses;



•

costs related to acquiring and manufacturing clinical trial materials;



•

costs related to compliance with regulatory requirements; and



•

payments related to licensed products and technologies.

        Weexpense all research and development costs in the periods in which they are incurred. Costs for certain development activities are recognized based on an evaluation of the progress tocompletion of specific tasks using information and data provided to us by our vendors and clinical sites. Nonrefundable advance payments for goods or services to be received in future periods for usein research and development activities are deferred and capitalized. The capitalized amounts are then expensed as the related goods are delivered and the services are performed.

        Fromour inception through March 31, 2018, we have incurred approximately $53.3 million in research and development expenses.

        Weplan to increase our research and development expenses for the foreseeable future as we continue to develop our therapeutic programs, and subject to the availability of additionalfunding, further advance the development of our therapeutic candidates for additional indications and begin to conduct clinical trials. We typically use our employee and infrastructure resourcesacross multiple research and development programs, and accordingly we have not historically allocated resources specifically to our individual clinical programs.

        Theprocess of conducting the necessary clinical research to obtain regulatory approval is costly and time-consuming, and the successful development of our therapeutic candidates ishighlyuncertain. As a result, we are unable to determine the duration and completion costs of our research and development projects or when and to what extent we will generate revenue from thecommercialization and sale of any of our therapeutic candidates.

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General and Administrative Expenses

        General and administrative expenses consist primarily of costs related to executive, finance, corporate development and administrative supportfunctions, including stock-based compensation expenses and benefits for personnel in general and administrative functions. Other significant, general and administrative expenses include rent,accounting and legal services, obtaining and maintaining patents or other intellectual property rights, the cost of various consultants, occupancy costs, insurance premiums and information systemscosts.

        Weexpect that our general and administrative expenses will increase as we operate as a public company, continue to conduct our clinical trials and prepare for commercialization. Webelieve that these increases will likely include increased costs for director and officer liability insurance, costs related to the hiring of additional personnel to support product commercializationefforts and increased fees for outside consultants, attorneys and accountants. We also expect to incur increased costs to comply with corporate governance, internal controls, investor relations anddisclosures, and similar requirements applicable to public companies.

Interest and Other Income (Expense), Net

        Interest and other income (expense), net consists primarily of accrued interest on outstanding convertible debt, amortization of debt discountassociated with the issuance of the convertible debt and interest on our line of credit with a financial institution.

Critical Accounting Policies and Estimates

        Our management's discussion and analysis of our financial condition and results of operations is based on our consolidated financial statements,which we have prepared in accordance with generally accepted accounting principles in the United States, or GAAP. The preparation of our consolidated financial statements requires us to make estimatesand assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of our financial statements, as well as the reportedexpenses during the reported periods. We evaluate these estimates and judgments on an ongoing basis. We base our estimates on historical experience and on various other factors that we believe arereasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities that are not readily apparent from other sources. Ouractual results may differ from these estimates under different assumptions or conditions.

        Wedefine our critical accounting policies as those accounting principles generally accepted in the United States that require us to make subjective estimates and judgments about mattersthat are uncertain and are likely to have a material impact on our financial condition and results of operations as well as the specific manner in which we apply those principles. We believe thecritical accounting policies used in the preparation of our financial statements that require significant estimates and judgments are as follows:

Use of Estimates

        The preparation of consolidated financial statements requires management to make estimates and assumptions that affect the reported amounts ofassets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements and the reported

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amountsof expenses during the reporting period. Such estimates include those related to the evaluation of our ability to continue as a going concern, revenue recognition, long-lived assets,convertible debt, income taxes, assumptions used in the Black-Scholes-Merton, or BSM, model to calculate the fair value of stock-based compensation, Monte Carlo Simulation, or MSM, model to calculatethe fair value of warrants, deferred tax asset valuation allowances, valuation of our common and convertible preferred stock, fair value assumptions used in the valuation of warrants issued withconvertible notes and convertible preferred stock warrant liabilities, preclinical study and clinical trial accruals and various accrued liabilities. Our actual results could differ from theseestimates.

Revenue Recognition

        Revenue is recognized in accordance with the Financial Accounting Standards Board, or FASB Accounting Standards Codification, or ASC 605,Revenue Recognition which requires that four basic criteria must be met before revenue can be recognized: (1) persuasive evidence of an arrangement exists; (2) delivery has occurred andtitle and the risksand rewards of ownership have been transferred to the client or services have been rendered; (3) the price is fixed or determinable; and (4) collectability is reasonably assured.

        During2017 and 2016, revenue includes grant awards and contract services entered into with government and or other agencies for specific research and development efforts. We recognizerevenue under such awards and contracts as the related qualified research and development expenses are incurred or under the milestone method, up to the limit of the prior approval funding amounts,and when we have determined that we have earned the right to receive the recognized portion according to the terms of the original grant awarded.

        During2016, all grant revenue was derived from a grant awarded by the National Institute of Health. All contract revenue was derived from a contract with the National Institute ofHealth and small amounts of fee-for-service contracts with other third parties. We recorded approximately $1,072,000 in grant revenue during the year ended December 31, 2016 for its ourcontract with the National Institute of Health. The contract ended in late 2016.

        During2017, all grant revenue was derived from our award agreement with the Cystic Fibrosis Foundation.

        InDecember 2016, we received an award from the Cystic Fibrosis Foundation for approximately $2,902,000. The agreement contains an upfront payment of $200,000 which is being recognizedstraight-line over the term of the contract as we believe the upfront fee relates to services performed throughout the contract period and the upfront fee does not represent a substantive milestonewithin the agreement. Recognition of revenue for the remaining payments under the agreement will be recognized using the milestone method as substantive milestones are met since there is uncertaintyas to whether the milestones will be met and our performance will be responsible for achieving the respective milestones. The milestones relate to both preclinical development and regulatory relatedactivities. The agreement also specifies that we are obligated to cumulatively spend on the development program at least an equal amount as it received from the non-profit organization. In the eventthat we do not spend as much as we received under the agreement, we are obligated to return any overage to the Cystic Fibrosis Foundation.

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        In2017, we entered into a collaborative research and development agreement with GSK. In accordance with the agreement, we received an upfront fee and annual fees and amounts fordevelopment work to be performed as specifically outlined under the agreement. The work to be performed was delineated into three specific research projects. In assessing the appropriate revenuerecognition related to a collaboration agreement, we first determined whether the arrangement includes multiple elements, such as the delivery of intellectual property rights and research anddevelopment services. The multiple elements were analyzed to determine whether the deliverables could be separated or whether they must be accounted for as a single unit of accounting. We determinedthat none of the elements had stand-alone value and that the agreement qualifies for treatment as a multiple element arrangement to be accounted for as a single unit of accounting. Amounts receivedprior to satisfying the revenue recognition criteria are recorded as deferred revenue in our balance sheet. Recognition of revenue under the contract will be based on the terms of the contract andwill be recognized under the proportional performance method derived from the completion of certain stages as defined within the contract.

        Forthe year ended December 31, 2017, approximately $771,000 was recorded as collaboration revenue related to our agreement with GSK. For the three months ended March 31,2018, no collaboration revenue was recorded under our agreement with GSK.

Research and Development

        Research and development costs are charged to operations as incurred.

Stock-Based Compensation

        We recognize compensation expense for all stock-based awards to employees and directors based on the grant-date estimated fair values, net of anestimated forfeiture rate. We recognize stock-based compensation cost for employees and directors on a straight-line basis over the requisite service period for the award. Stock-based compensationexpense is recognized only for those awards that are ultimately expected to vest. We estimate forfeitures based on an analysis of historical employee turnover and will continue to evaluate theappropriateness of the forfeiture rate based on actual forfeiture experience, analysis of employee turnover and other factors. We will revise the forfeiture estimate, if necessary, in subsequentperiods if actual forfeitures differfrom those estimates. Changes in forfeiture estimates impact stock-based compensation cost in the period in which the change in estimate occurs.

        TheBSM option pricing model incorporates various highly sensitive assumptions, including the fair value of our common stock, expected volatility, expected term and risk-free interestrates. The weighted average expected life of options was calculated using the simplified method as prescribed by the SEC's Staff Accounting Bulletin No. 107, or SAB No. 107. Thisdecision was based on the lack of relevant historical data due to our limited historical experience. In addition, due to our limited historical data, the estimated volatility also reflects theapplication of SAB No. 107, incorporating the historical volatility of comparable companies whose stock prices are publicly available. The risk-free interest rate for the periods within theexpected term of the option is based on the U.S. Treasury yield in effect at the time of grant. The dividend yield was zero, as we have never declared or paid dividends and have no plans to do so inthe foreseeable future.

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        Weaccount for stock-based compensation arrangements with nonemployees by recording the expense of such services based on the estimated fair value of the common stock at the measurementdate. The value of the equity instrument, including adjustment to fair value at each balance sheet date, is charged to earnings over the term of the service agreement.

        Dueto the absence of a public market trading for our common stock, it is necessary to estimate the fair value of the common stock underlying our stock-based awards when performing fairvalue calculations. The estimated fair value of our common stock was determined using methodologies, approaches and assumptions consistent with the American Institute of Certified Public Accountants,or AICPA, Practice Aid: Valuation of Privately-Held-Company Equity Securities Issued as Compensation.

        Thesame methods were applied to estimate the fair value of member shares in the predecessor LLC. We expect to utilize fair market values as determined by trades in the publicmarkets at such time as our shares trade publicly and an observable market exists.

Fair Value of Common Stock

        To assist our board of directors with the determination of the exercise price of our stock options and the fair value of the common stockunderlying the options, we obtained third-party valuations of our common stock as of various dates since we began granting options, with concluded fair values between $0.45 per share and $2.68 pershare. Our board of directors considered the fair values of the common stock derived in the third-party valuations as one of the factors it considered when setting the exercise prices for optionsgranted. The valuations were performed in accordance with applicable elements of the AICPA Practice Aid. The AICPA Practice Aid identifies various available methods for allocating enterprise valueacross classes and series of capital stock to determine the estimated fair value of common stock at each valuation date. In accordance with the AICPA Practice Aid, we considered the followingmethods:

•

Option Pricing Method.  Under the option pricing method, or OPM, shares arevalued by creating a series of call options with exercise prices based on the liquidation preferences and conversion terms of each equity class. The estimated fair values of the preferred and commonstock are inferred by analyzing these options.



•

Probability-Weighted Expected Return Method.  Under the probability-weightedexpected return method, or PWERM, common equity value is based upon an analysis of various future outcomes, such as an initial public offering, or IPO, merger or sale, dissolution, or continuedoperation as a private enterprise until a later exit date. The future allocated value is based upon the probability-weighted present values of expected future investment returns, considering each ofthe possible outcomes available to the enterprise, as well as the rights of each security class.

        Ourboard of directors also considered a range of objective and subjective factors and assumptions in estimating the fair value of our common stock on the date of grant, including:progress of our research and development efforts; our operating results and financial condition, including our levels of available capital resources; rights and preferences of our common stockcompared to the rights and preferences of our other outstanding equity securities; our stage of development and material risks related to our business; our commercial success in regard to our cathetersales; the achievement of enterprise milestones; the valuation of publicly-traded

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companiesin the life sciences and biotechnology sectors, as well as recently completed mergers and acquisitions of peer companies; equity market conditions affecting comparable public companies; thelikelihood of achieving a liquidity event for the shares of common stock, such as an initial public offering given prevailing market and biotechnology sector conditions; and that the grants involvedilliquid securities in a private company. The fair value of our common stock as of December 31, 2017 and 2016 and March 31, 2018 was $2.68 and $1.50 and $2.79, respectively.

        Followingthe closing of this offering, the fair value of our common stock will be determined based on the closing price of our common stock on The Nasdaq Capital Market on the dateimmediately prior to the date of grant.

Income Taxes

        We account for income taxes under the liability method. Under this method, deferred tax assets and liabilities are determined based on thedifference between the financial statement and tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to affect taxable income.Valuation allowances are established when necessary to reduce deferred tax assets to the amounts expected to be realized.

        Weassess all material positions taken in any income tax return, including all significant uncertain positions, in all tax years that are still subject to assessment or challenge by therelevant taxing authorities. Assessing an uncertain tax position begins with the initial determination of the positions sustainability and is measured at the largest amount of benefit that is greaterthan fifty percent likely of being realized upon ultimate settlement. At each balance sheet date, unresolved uncertain tax positions must be reassessed, and we will determine whether (i) thefactors underlying the sustainability assertion have changed and (ii) the amount of the recognized benefit is still appropriate. The recognition and measurement of tax benefits requiressignificant judgment. Judgments concerning the recognition and measurement of a tax benefit might change as new information becomes available.

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Results of Operations

Comparison of the Three Months Ended March 31, 2018 and 2017

        The following table summarizes our results of operations for the three months ended March 31, 2018 and 2017 (in thousands):

        Grant Revenue.    Grant revenue increased by approximately $300,000 from $22,000 for the nine months ended March 31, 2017 to $322,000for thethree months ended March 31, 2018 due primarily to triggering a milestone related to the Cystic Fibrosis Foundation ("CF Foundation") award.

        Research and Development Expenses.    Research and development expenses increased by approximately $1,808,000 from $4,818,000 for the threemonths endedMarch 31, 2017 to $6,626,000 for the three months ended March 31, 2018 due primarily to increased activity in our Phase 2 Aerucin clinical trial, work performed on Panaecin aspart of our award agreement with the CF Foundation, an ongoing toxicology study, manufacturing drugs for current and future trials and an increase in personnel and related expenses.

        General and Administrative Expenses.    General and administrative expenses increased by approximately $39,000 from $1,027,000 for thethree monthsended March 31, 2017 to $1,066,000 for the three months ended March 31, 2018 due primarily to an increase in professional services, personnel related costs and other administrativeexpenses partially offset by lower stock-based compensation charges.

        Interest and Other Income (Expense), net.    Interest and other income (expense), net increased by approximately $49,000 from $25,000 forthe threemonths ended March 31, 2017 to $74,000 for the three months ended March 31, 2018 due primarily to a higher interest rate earned on our cash balances.

        Change in Fair Value of Warrant Liability.    Change in fair value of warrant liability for the three months ended March 31, 2018decreased byapproximately $2,376,000 from $2,414,000 for

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thethree months ended March 31, 2017 to $38,000 for the three months ended March 31, 2018 due primarily to a smaller increase in the underlying fair value of our Series Aconvertible preferred stock for the three months ended March 31, 2018.

Comparison of the Year Ended December 31, 2017 and 2016

        The following table summarizes our results of operations for the year ended December 31, 2017 and 2016 (in thousands):

 

        Contract Revenue.    Contract revenue decreased by approximately $2,068,000 from $2,068,000 for the year ended December 31, 2016 to$0 for theyear ended December 31, 2017 due primarily to the completion of our biodefense contract with the NIH at the end of the third quarter of 2016, and the completion of our contract with GSK in 2016.

        Collaboration Revenue.    Collaboration revenue increased by approximately $771,000 from $0 for the year ended December 31, 2016 to$771,000 forthe year ended December 31, 2017 due to the triggering of a milestone on our GSK collaboration agreement.

        Grant Revenue.    Grant revenue decreased by approximately $112,000 from $201,000 for the year ended December 31, 2016 to $89,000 forthe yearended December 31, 2017 due primarily to the completion of our NIH grant for rotavirus which ended during the middle of 2016.

        Cost of Contract Revenue.    Cost of contract revenue decreased by approximately $1,927,000 from $1,927,000 for the year endedDecember 31, 2016to $0 for the year ended December 31, 2017 due to the completion of our biodefense contract with the NIH our contract with GSK in 2016.

        Research and Development Expenses.    Research and development expenses increased by approximately $11,177,000 from $6,261,000 for theyear endedDecember 31, 2016 to $17,438,000 for the year ended December 31, 2017 due primarily to increased activity in our Phase 2 Aerucin

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clinicaltrial, manufacturing drugs for current and future trials and an increase in personnel and related expenses.

        General and Administrative Expenses.    General and administrative expenses increased by approximately $1,195,000 from $1,965,000 for theyear endedDecember 31, 2016 to $3,160,000 forthe year ended December 31, 2017 due primarily to an increase in stock-based compensation charges, professional services, personnel related costs and other administrative expenses.

        Interest and Other Income (Expense), net.    Interest and other income (expense), net for the year ended December 31, 2017 increased byapproximately$600,000 from an expense of $366,000 for the year ended December 31, 2016 to income of $234,000 for the year ended December 31, 2017 due primarily to more interest income from a higheraverage cash balance as compared to amortization of debt discount related to the issuance of common stock warrants attached to the convertible notes which matured in December 2016.

        Change in Fair Value of Warrant Liability.    Change in fair value of warrant liability for the year ended December 31, 2016 increasedbyapproximately $4,980,000 from $172,000 for the year ended December 31, 2016 to $5,152,000 for the year ended December 31, 2017 due to an increase in the underlying fair value of theCompany's Series A convertible preferred stock and the issuance of additional preferred warrants during 2017.

Liquidity, Capital Resources and Going Concern

        We have not yet achieved commercialization of its products and has a cumulative net loss from its operations. We will continue to incur netlosses for the foreseeable future. Our consolidated financial statements have been prepared assuming that we will continue as a going concern. We will require additional capital to meet our long-termoperating requirements. We expect to raise additional capital through the sale of equity and/or debt securities. Historically, our principal sources of cash have included proceeds from grant funding,fees for services performed, issuances of convertible debt and the sale of our preferred stock. Our principal uses of cash have included cash used in operations. We expect that the principal uses ofcash in the future will be for continuing operations, funding of research and development including our clinical trials and general working capital requirements.

Cash Flows

        Our net cash flow from operating, investing and financing activities for the periods below were as follows (in thousands):

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        Cash Flows from Operating Activities.    Net cash used in operating activities was approximately $4,437,000 for the three months endedMarch 31,2018, which was primarily due to our net loss of $7,334,000. The difference between our net loss and our net cash used in operating activities was due primarily to non-cash expenses and an increase inour liabilities and deferred revenue partially offset by a decrease in prepaid expenses and other assets. Net cash used in operating activities was approximately $3,307,000 for the three months endedMarch 31, 2017, which was primarily due to our net loss of $8,212,000. The difference between our net loss and our cash used in operating activities was due primarily to non-cash expenses andan increase in our liabilities and deferred revenue partially offset by a decrease in prepaid expenses and other assets.

        Cash Flows from Investing Activities.    Net cash used in investing activities of $272,000 during the three months ended March 31,2018 was dueto the cash paid for equipment purchases. There was no cash used in investing activities during the three months ended March 31, 2017.

        Cash Flows from Financing Activities.    Net cash provided by financing activities of $4,496,000 during the three months endedMarch 31, 2017 wasdue to the receipt of cash from a stock subscription agreement entered into during the previous year.

        Ournet cash flow from operating, investing and financing activities for the periods below were as follows (in thousands):

        Cash Flows from Operating Activities.    Net cash used in operating activities was approximately $17,557,000 for the year endedDecember 31,2017, which was primarily due to our net loss of $24,656,000. The difference between our net loss and our net cash used in operating activities was due primarily to non-cash expenses and a decrease inour accounts receivable and an increase in our liabilities and deferred revenue partially offset by an increase in prepaid expenses and other assets. Net cash used in operating activities wasapproximately $6,091,000 for the year ended December 31, 2016, which was primarily due to our net loss of $8,422,000. The difference between our net loss and our net cash used in operatingactivities was due primarily to non-cash expenses and a decrease in our accounts receivable, prepaid expenses and deposits.

        Cash Flows from Investing Activities.    Net cash used in investing activities of $698,000 during the year ended December 31, 2017was due to thecash paid for equipment purchases. Net cash used in investing activities of $15,000 during the year ended December 31, 2016 was due to the cash paid for an equipment purchase.

        Cash Flows from Financing Activities.    Net cash provided by financing activities of $21,060,000 during the year ended December 31,2017 was theresult of $21,060,000 of stock subscription proceeds and net proceeds received from the issuance of our Series A convertible preferred stock. Net cash provided by financing activities of $25,505,000during the year ended December 31, 2016

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wasthe result of $25,805,000 of net proceeds received from the issuance of our Series A convertible preferred stock partially offset by paying off our line of credit in the amount of $300,000.

Future Funding Requirements

        To date, we have generated revenue from grants and contract services performed and the issuance of convertible preferred stock. We do not knowwhen, or if, we will generate any revenue from our development stage therapeutic programs. We do not expect to generate any revenue from sales of our therapeutic candidates unless and until we obtainregulatory approval. At the same time, we expect our expenses to increase in connection with our ongoing development activities, particularly as we continue the research, development and clinicaltrials of, and seek regulatory approval for, our therapeutic candidates. Upon the closing of this offering, we expect to incur additional costs associated with operating as a public company. Inaddition, subject to obtaining regulatory approval of any of our therapeutic candidates, we expect to incur significant commercialization expenses for product sales, marketing, manufacturing anddistribution. We anticipate that we will need additional funding in connection with our continuing operations. Additionally, if the Cystic Fibrosis Foundation does not continue to provide sufficientlevel of funding support, we may not be able to complete the Phase 1/2a clinical trial relating to AR-501.

        Basedupon our current operating plan, we believe that the net proceeds from this offering, together with our existing cash and cash equivalents, will enable us to fund our operationsfor at least the 12 months after the date of this prospectus. We intend to use the net proceeds we receive from this offering for clinical trials of our lead programs, working capital, researchand development of additional future products or therapies and general corporate purposes. We have based our estimates on assumptions that may prove to be wrong, and we may use our available capitalresources sooner than we currently expect. Because of the numerous risks and uncertainties associated with the development and commercialization of our therapeutic candidates, we are unable toestimate the amounts of increased capital outlays and operating expenditures necessary to complete the development of our therapeutic candidates.

        Ourfuture capital requirements will depend on many factors, including:

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the progress, costs, results and timing of our clinical trials;



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FDA acceptance, if any, of our therapies for infectious diseases and for other potential indications;



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the outcome, costs and timing of seeking and obtaining FDA and any other regulatory approvals;



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the number and characteristics of product candidates that we pursue, including our product candidates in preclinical development;



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the ability of our product candidates to progress through clinical development successfully;



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our need to expand our research and development activities;



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the costs of acquiring, licensing or investing in businesses, products, product candidates and technologies;

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•

our ability to maintain, expand and defend the scope of our intellectual property portfolio, including the amount and timing of any payments wemay be required to make, or that we may receive, in connection with the licensing, filing, prosecution, defense and enforcement of any patents or other intellectual property rights;



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our need and ability to hire additional management and scientific, medical and administrative personnel;



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the effect of competing technological and market developments; and



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our need to implement additional internal systems and infrastructure, including financial and reporting systems.

        Untilsuch time that we can generate meaningful revenue from the sales of approved therapies and products, if ever, we expect to finance our operating activities through public orprivate equity or debt financings, government or other third-party funding, and other collaborations, strategic alliances and licensing arrangements or a combination of these approaches. To the extentthat we raise additional capital through the sale of equity or convertible debt securities, the ownership interests of our common stockholders will be diluted, and the terms of these securities mayinclude liquidation or other preferences that adversely affect the rights of our common stockholders. Debt financing, if available, may involve agreements that include conversion discounts orcovenants limiting or restricting our ability to take specific actions, such as incurringadditional debt, making capital expenditures or declaring dividends. If we raise additional funds through government or other third-party funding, marketing and distribution arrangements or othercollaborations, or strategic alliances or licensing arrangements with third parties, we may have to relinquish valuable rights to our technologies, future revenue streams, research programs or productcandidates or to grant licenses on terms that may not be favorable to us.

Off-Balance Sheet Arrangements

        During the periods presented we did not have, nor do we currently have, any off-balance sheet arrangements as defined under the rules of theSEC.

JOBS Act Accounting Election

        The JOBS Act permits an "emerging growth company" such as us to take advantage of an extended transition period to comply with new or revisedaccounting standards applicable to public companies. We are choosing to take advantage of this provision and, as a result, we will adopt the extended transition period available under the JOBS Actuntil the earlier of the date we (i) are no longer an emerging growth company or (ii) affirmatively and irrevocably opt out of the extended transition period provided under the JOBS Act.

Recent Accounting Pronouncements

        In July 2017, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2017-11, Earnings PerShare (Topic 260); Distinguishing Liabilities from Equity (Topic 480); Derivatives and Hedging (Topic 815): (Part I) Accounting for Certain Financial Instruments with DownRound Features; (Part II) Replacement of the Indefinite Deferral for Mandatorily Redeemable Financial Instruments of Certain Nonpublic Entities and Certain Mandatorily Redeemable NoncontrollingInterests with a Scope Exception ("ASU

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2017-11").ASU 2017-11 allows companies to exclude a down round feature when determining whether a financial instrument (or embedded conversion feature) is considered indexed to the entity's ownstock. As a result, financial instruments (or embedded conversion features) with down round features may no longer be required to be accounted for as derivative liabilities. A company will recognizethe value of a down round feature only when it is triggered and the strike price has been adjusted downward. For equity-classified freestanding financial instruments, an entity will treat the value ofthe effect of the down round as a dividend and a reduction of income available to common shareholders in computing basic earnings per share. For convertible instruments with embedded conversionfeatures containing down round provisions, entities will recognize the value of the down round as a beneficial conversion discount to be amortized to earnings. ASU 2017-11 is effective for fiscalyears beginning after December 15, 2019, and interim periods within those fiscal years. Early adoption is permitted. The guidance in ASU 2017-11 can be applied using a full or modifiedretrospective approach. We are currently evaluating the impact of adopting this guidance.

        InMay 2017, the FASB issued ASU 2017-09, "Compensation — Stock Compensation (Topic 718): Scope of Modification Accounting," to provide clarity and reduce bothdiversity in practice and cost complexity when applying the guidance in Topic 718 to a change to the terms and conditions of a stock-based payment award. ASU 2017-09 also provides guidanceabout the types of changes to the terms or conditions of a share-based payment award that require an entity to apply modification accounting in accordance with Topic 718. For all entities,including emerging growth companies, the standard is effective for annual periods beginning after December 15, 2017, and for interim periods therein. Early adoption is permitted. The adoptionof this standard did not have a material effect.

        InJanuary 2017, the FASB issued ASU No. 2017-04, "Intangibles — Goodwill and Other: Simplifying the Test for Goodwill Impairment," to simplify thesubsequent measurement of goodwill by eliminating Step 2 from the goodwill impairment test. The standard is effective for public entities for annual or any interim goodwill impairment tests in annualreporting periods beginning after December 15, 2019. For all other entities, including emerging growth companies, the standard is effective for annual or any interim goodwill impairment testsin annual reporting periods beginning after December 15, 2021. Early adoption of this standard is permitted. We are currently evaluating the impact of adopting this guidance.

        InAugust 2016, the FASB issued ASU 2016-15, "Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments." ASU 2016-15 reduces diversity inpractice by providing guidance on the classification of certain cash receipts and payments in the statement of cash flows. ASU 2016-15 clarifies that when cash receipts and cash payments have aspectsof more than one class of cash flows and cannot be separated, classification will depend on the predominant source or use. ASU 2016-15 is effective on a retrospective basis for fiscal years, and forinterim periods within those fiscal years, beginning after December 15, 2018, with early adoption permitted. We are currently evaluating the impact of adopting this guidance.

        InApril 2016, the FASB issued ASU No. 2016-10, "Revenue from Contract with Customers: Identifying Performance Obligations and Licensing." The amendments in this update clarifythe two following aspects (a) contracts with customers to transfer goods and services in exchange for consideration and (b) determining whether an entity's promise to grant a licenseprovides a customer with either a right to use the entity's intellectual property (which is satisfied at a point in

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time)or a right to access the entity's intellectual property (which is satisfied over time). The amendments in this Update are intended to reduce the degree of judgment necessary to comply withTopic 606. The new standard is effective for fiscal years beginning after December 15, 2018. We are currently evaluating the impact of adopting this guidance.

        InMarch 2016, the FASB issued ASU No. 2016-09, "Improvements to Employee Share-Based Payment Accounting," which is intended to improve the accounting for employee share-basedpayments. The ASU simplifies several aspects of the accounting for share-based payment award transactions, including; the income tax consequences, classification of awards as either equity orliabilities, and the classification on the statement of cash flows. The new standard is effective for fiscal years beginning after December 15, 2017, and upon adoption, an entity should applythe amendments by means of a cumulative-effect adjustment to the balance sheet at the beginning of the first reporting period in which the guidance is effective. Early adoption is permitted. Theadoption of this standard did not have a material effect.

        InFebruary 2016, the FASB issued ASU No. 2016-02, "Leases (Topic 842)." The pronouncement requires the recognition of a liability for lease obligations and a correspondingright-of-use asset on the balance sheet and disclosure of key information about leasing arrangements. This pronouncement is effective for reporting periods beginning after December 15, 2019using a modified retrospective adoption method. We are currently evaluating the impact of adopting this guidance.

        InMay 2014, the FASB issued ASU No. 2014-19, "Revenue from Contracts with Customers." The objective of ASU 2014-19 is to establish a single comprehensive model for entities touse in accounting for revenue arising from contracts with customers and will supersede most of the existing revenue recognition guidance, including industry-specific guidance. The core principle ofASU 2014-09 is that an entity recognizes revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to beentitled in exchange for those goods or services. The new guidance is effective for annual reporting periods (including interim periods within those periods) beginning after December 15, 2018.Early adoption is not permitted. The standard permits the use of either a retrospective or modified retrospective (cumulative effect) transition method. We are currently evaluating the impact ofadopting this guidance.

Quantitative and Qualitative Disclosure about Market Risk

        We do not believe that our cash and cash equivalents have significant risk of default or illiquidity. While we believe our cash and cashequivalents do not contain excessive risk, we cannot provide absolute assurance that in the future our investments will not be subject to adverse changes in market value. In addition, we maintainsignificant amounts of cash and cash equivalents at one or more financial institutions that are in excess of federally insured limits.

        Inflationgenerally affects us by increasing our cost of labor and clinical trial costs. We do not believe that inflation has had a material effect on our results of operations duringthe periods presented.

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BUSINESS

Overview

        We are a late-stage biopharmaceutical company focused on the discovery and development of targeted immunotherapy using fully human monoclonalantibodies, or mAbs, to treat life-threatening infections. mAbs represent a fundamentally new treatment approach in the infectious disease market and are designed to overcome key issues associatedwith current therapies, including drug resistance, short duration of response, negative impact on the human microbiome, and lack of differentiation between treatment alternatives. Our proprietaryproduct pipeline is comprised of fully human mAbs targeting specific pathogens associated with life-threatening bacterial infections, primarily hospital-acquired pneumonia, or HAP, andventilator-associated pneumonia, or VAP. Three of our product candidates have exhibited promising preclinical data and clinical data are available from two completed studies and are in pivotal trialstage. Our lead product candidate, AR-301, also referred to as Salvecin, targets the alpha toxin produced by gram-positive bacteria Staphylococcusaureus, or S. aureus, a common pathogen associated with HAP and VAP. In contrast to other programs targeting S. aureus toxins,we are developing AR-301 as a treatment of pneumonia, rather than prevention of S. aureus colonized patients from progressionto pneumonia. We have conducted an end-of-Phase 2 meeting with the US Food and Drug Administration, or FDA, and expect to initiate a Phase 3 pivotal trial for AR-301 in the second halfof 2018. In addition, we are developing AR-105, also referred to as Aerucin, and AR-101, also referred to as Aerumab. AR-105 targets gram-negative bacteria Pseudomonasaeruginosa, or P. aeruginosa, and has been granted Fast-Track designation by the FDA. We initiated a global Phase 2 trialfor AR-105 in HAP and VAP patients in the second quarter of 2017. AR-101 also targets gram-negative bacteria P. aeruginosa and has been granted orphandrug designation in the U.S. and EU. We plan to initiate a Phase 2/3 pivotal trial for AR-101 in the second half of 2019.

        Themajority of candidates from our product pipeline are derived by employing our differentiated antibody discovery platform called MabIgX. This platform is designed to comprehensivelyscreen the B-cell repertoire and isolate human antibody-producing B-cells from individuals who have either successfully overcome an infection by a particular pathogen or have been vaccinated against aparticular pathogen. We believe that B-cells from these patients are the ideal source of highly protective and efficacious mAbs which can been administered safely to other patients. MabIgX also allowsfor rapid, high-throughput screening of B-cells and direct manufacturing of mAbs. As a result, we can significantly reduce time for antibody discovery and manufacturing compared to conventionalapproaches.

        Ourinitial clinical indication is for adjunctive therapeutic treatment with standard of care, or SOC, antibiotics for HAP and VAP. Mortality and morbidity associated with HAP and VAP inthe intensive care units, or ICU, remain high despite aggressive treatment with SOC antibiotics. Current SOC antibiotics used to treat HAP and VAP typically involve a combination of several broadspectrum antibiotics that are prescribed empirically at the start of treatment. The specificempirical antibiotic regimens that are prescribed vary widely among physicians, and generally resulted in modest clinical benefits due to a number of reasons, including the frequent mismatch of theantibiotics regimen to the etiologic agent and/or infection by an antibiotic resistant strain. Recently, rapid diagnostic tests have been introduced that allow the identification of infection-

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causingagents within hours. These increasingly common tests allow physicians to prescribe a targeted anti-infective drug, rather than a broad-spectrum antibiotic. This evidenced-based treatmentapproach is designed to remove issues associated with SOC antibiotics treatment practices, and to improve the effectiveness of SOC antibiotics, while not competing directly with antibiotics. Incontrast to the lack of differentiation among SOC antibiotics, mAbs are highly differentiated from SOC antibiotics in mechanism of action and pharmacodynamic profile, and thus are well suited tocomplement antibiotics action and are effective against antibiotic resistant bacteria. To emphasize the benefits of our product candidates as an adjunctive therapy, we design clinical trials based onsuperiority endpoints.

        HAPand VAP pose serious challenges in the hospital setting, as SOC antibiotics are becoming inadequate in treating infected patients. There are approximately 3,000,000 cases ofpneumonia reported in the U.S. per year and approximately 628,000 annual cases of HAP and VAP caused by Gram negative bacteria and MRSA (DRG, 2016). These patients are typically at high risk ofmortality, which is compounded by other life-threatening co-morbidities and the rise in antibiotic resistance. Epidemiology studies estimate that the probability of death attributed to S. aureus rangesfrom 29% to 55% and P. aeruginosa ranges from 24% to 76%. In addition, pneumoniainfections can prolong patient stays in ICUs and the use of mechanical ventilation, creating a major economic burden on patients, hospital systems and payors. For example, ICU cost of care for aventilated pneumonia patient is approximately $10,000 per day, and the duration of ICU stay is typically twice that of a non-ventilated patient (Infection Control and Hospital Epidemiology. 2010, vol.31, pp. 509-515). The average cost of care per pneumonia patient is approximately $41,250 which increases 86% for HAP/VAP patients to approximately $76,730. We estimate that our three clinical mAbcandidates have an addressable market of $25 billion and the potential to address approximately 325,000 HAP and VAP patients in the U.S.

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        Ourproprietary pipeline is primarily focused on severe lung infections and is comprised of six wholly-owned product candidates which are highlighted below.

Figure 1
Our Product Pipeline

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AR-301 (Salvecin, or tosatoxumab) is a fullyhuman immunoglobulin 1, or IgG1, mAb targeting the gram-positive bacteria S. aureus alphatoxin. We are developing AR-301 initially as an adjunctiveimmunotherapy in combination with SOC antibiotics to treat acute pneumonia caused by S. aureus infection. We filed an IND for AR-301 on June 5,2015. We have recently completed a randomized, double-blind, placebo-controlled Phase 2a trial in 48 HAP and VAP patients. The trial met its primary endpoint of tolerability. AR-301 wasgenerally well tolerated with no serious adverse events, or SAEs, related to the product candidate, and its pharmacokinetic properties were consistent with that of human IgG1. In addition, the trialshowed trends towards benefit in various patient benefits related endpoints, including improvements in time on ventilator for VAP patients, microbiological eradication rate, time to microbiologicaleradication, and overall ICU and hospital stays for AR-301 plus SOC antibiotics compared to antibiotics alone. We expect to initiate a Phase 3 pivotal trial in VAP patients in the second halfof 2018. AR-301 has been granted Fast-Track designation by the FDA, orphan drug designation in the EU, and has filed for orphan drug designation in the U.S.



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AR-105 (Aerucin) is a fully human IgG1 mAb targeting the gram-negative bacteria P. aeruginosa. We aredeveloping AR-105 initially as an adjunctive immunotherapy to treat acute pneumonia caused by P.aeruginosa infection. We filed an IND for AR-105 on

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January 8,2015. In a recent Phase 1 trial in healthy adults, AR-105 was well-tolerated at all dose levels with no SAEs, and its pharmacokinetic profile was consistent with that of humanIgG1. In preclinical studies, AR-105 exhibited broad binding profile and mediated killing of over 90% of clinical isolates tested. AR-105 also demonstrated protective effects in prophylaxis animalmodels and synergistic effect in combination with antibiotics. We initiated a global Phase 2 trial in HAP/VAP patients in the second quarter of 2017 and expect to report interim data in thefirst half of 2019. AR-105 has been granted Fast-Track designation by the FDA.

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AR-101 (Aerumab) is a fully human immunoglobulin M, or IgM, mAb targeting the gram-negativebacteria P. aeruginosa serotype O11. We filed an Investigational Medicinal Product Dossier, or IMPD, with the EU on October 22, 2004. We plan tofile an IND after the initiation of our Phase 2/3 pivotal trial described below. We have completed a Phase 1 trial in healthy adults and a Phase 2a trial in 27 HAP and VAPpatients. In the Phase 2a trial, AR-101 plus SOC antibiotics was generally well tolerated. The per protocol population demonstrated numeric improvement over standalone antibiotics acrossmultiple clinical endpoints, including initial clinical resolution rate, time to initial clinical resolution, time on ventilator or in ICU and all-cause mortality was seen. We plan to initiate a Phase2/3 pivotal trial in the second half of 2019. AR-101 has been granted orphan drug designation in the U.S. and in the EU.



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AR-401 is our mAb discovery program aimed at treating infections caused by Acinetobacter baumannii, agram-negative bacterium that is increasingly prevalent in blood stream, lung and skin infections. We used our MabIgXtechnology to identify novel targets and select several fully human mAb candidates that bind to outer membrane proteins of the bacteria. We intend to select a development candidate for additionalpreclinical studies.



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AR-201 is a fully human IgG1 mAb with high affinity for respiratory syncytial virus, or RSV,glycoprotein F and neutralizes diverse clinical isolates of RSV. In in vivo preclinical studies, AR-201 has shown to be 12-fold more potent than Synagisin a head-to-head comparison study, a currently marketed drug for pediatric RSV. AR-201 has also been shown to bind to RSV strains that are resistant to Synagis.



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AR-501 (Panaecin) is a broad spectrum small molecule anti-infective we are developing inaddition to our targeted mAb product candidates. This product candidate is currently in late preclinical studies and is funded by the Cystic Fibrosis Foundation through Phase 1/2a trial. AR-501is administered as an inhalable aerosol to treat lung infections in cystic fibrosis patients. Preclinical studies have shown that mice infected with P.aeruginosa can be rescued with a single inhalation exposure of aerosolized AR-501. We expect to file the Investigational New Drug, or IND, application and initiate aPhase 1/2a trial in healthy adults and Cystic Fibrosis patients in the second half of 2018.

        Todate, we have raised over $60 million in private investments. Furthermore, we have been able to augment our own financial resources by obtaining approximately$40 million of non-dilutive awards and grants, including approximately $32 million from the Department of Health and Human Services, or DHHS, the National Institute of Health, or NIH,and the Biomedical Advanced Research and Development Authority, or BARDA, and approximately $7.5 million from the Department of Defense, PATH/Gates Foundation, the Cystic Fibrosis

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Foundationand other strategic research and development collaborations. We believe that our ability to attract significant financial investments and grant funding underscores the recognized need fornew anti-infective products and the strength of our product candidate portfolio.

        Wehave assembled a senior management team with substantial product development experience and a successful track record of navigating complex drug development and regulatory pathways.Our management team has over 175 years of combined drug development experience from proven biopharmaceutical companies, such as Abgenix, Inc. Aviron, Genentech, Inc.,GlaxoSmithKline plc, Celgene Corporation, MedImmune, LLC and Novartis AG among others, and has contributed to the development and launch of products with multi-billions in annual sales.

Strategy

        Our goal is to become a global leader in anti-infective immunotherapy by discovering, developing and commercializing best-in-class mAbs with thepotential to significantly improve upon SOC treatments for life-threatening infections. Key elements of our strategy are as follows:

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Efficiently advance our product candidates to worldwide approval andcommercialization.  We intend to leverage the favorable regulatory environment in the infectious disease market and closely interact with the FDA,the European Medicines Agency, or the EMA, and other regulatory agencies to create efficient clinical development plans and expedite approval pathways for our product candidates. For developmentoutside of the U.S., we will evaluate potential regional collaborations which may lead to more rapid and cost-effective path to market compared to a standalone strategy.



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Obtain favorable regulatory designations for our productcandidates.  Regulatory designations can provide numerous benefits for our product candidates, including expedited development pathway and review,market exclusivity, premium pricing and faster product adoption among others. To date, we have successfully applied for and received Fast Track Designation for AR-301 and AR-105, orphan drugdesignation in the U.S. for AR-101 and orphan drug designation in the EU for AR-301 and AR-101. We seek to obtain these designations in addition to others, such as Qualified Infectious DiseaseProduct, or QIDP, and Breakthrough Therapy designations, for our existing and future product candidates to enhance their likelihood of approval and commercial success.



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Demonstrate pharmacoeconomic benefits of our productcandidates.  We aim to change the treatment paradigm of infectious disease by focusing on the pharmacoeconomic benefits of our product candidates.We utilize superiority clinical trial designs rather than non-inferiority designs typically used by antibiotics, as positive outcomes from such trials can better demonstrate efficacy and safetyadvantages of our product candidates. We target indications where our product candidates may address drivers of high cost of care in hospital settings, such as time on ventilator, ICU stay andhospital stay. In addition, we will continue to invest resources in market research to better identify and quantify pharmacoeconomic benefits of our product candidates.



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Implement a targeted commercializationstrategy.  Our core therapeutic indications can be addressed with a relatively small, specialized sales organization. As such, we intend to buildand operate our own dedicated sales force to directly market our products in the U.S., to

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hospitals.For geographies outside of the U.S., we may seek commercial partners with more regional expertise to maximize the commercial value of our products.

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Employ our MabIgX antibody discovery platform to expand our productpipeline.  We believe our MabIgX platform offers us distinct advantages over our peers in terms of new product candidate discovery anddevelopment. We can screen and identify functionally optimized B-cells from patients, and directly manufacture mAbs, by up to one year faster then traditional technologies. Our differentiated approachreduces mAb discovery and manufacturing time by up to one year compared to traditional technologies. We believe that using our technology, clinical drug supplies can be manufactured within one yearfrom screening the patient's blood. We intend to continue to use our MabIgX platform to generate new product candidates for bacterial, viral and other infectious diseases where mAb immunotherapy hasthe potential to address deficiencies of current treatment alternatives.



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Continue to pursue grant funding and strategiccollaborations.  To date, we have been awarded approximately $40 million in non-dilutive grant funding. We believe that the industry's needfor novel products, such as our product candidates, makes non-dilutive funding from governmental agencies and research organizations more accessible. Furthermore, our robust pipeline of wholly-ownedproduct candidates and highly productive discovery platform offer opportunities for value-accretive partnerships. We will continue to pursue grant funding and strategic collaborations in addition totraditional financings.

Market Opportunities

        Our mission is to improve the treatment of infectious diseases, particularly the deficiencies of conventional antibiotics. It is widelyrecognized that there is a growing problem of antibiotic resistance at a time when the pipeline of antibiotics is dwindling and much of the development activity currently ongoing is devoted tomodifications of existing classes of antibiotics. We believe this antibiotic strategy has merely delayed rather than solved the underlying resistance problem as evidenced by the spread of drugresistant bacteria, particularly in the hospital settings. The drug resistance and adverse impact on the human microbiome, particularly the gut microbial flora, brought about by frequent use ofbroad spectrum antibiotics increased the need for targeted, narrow spectrum anti-infectives that counteract only the etiologic bacterial agent. The ability to identify the infection-causing agent hassignificantly improved in recent years because of the availability and proliferation of rapid diagnostic tests. These diagnostics have enabled the identification of pathogen profiles within hours ofpatient sample collection, thus providing physicians with the rapid, precise information necessary to make more informed treatment decisions. Given the identity of the specific pathogen responsiblefor an infection, we believe the physician is more likely to prescribe a targeted anti-infective, rather than a broad-spectrumantibiotic. Therefore, we believe that the treatment of infectious diseases will see a paradigm shift from broad spectrum antibiotic utilization to narrow, targeted anti-infectives. Such paradigmshift is similar to that observed in oncology starting in the early 2000s, from broad acting chemotherapies to targeted immune-oncology mAbs. Therefore, we believe that the opportunity for applicationof mAbs in infectious diseases is highly attractive.

        Thecurrent small molecule antibiotics market is crowded, highly competitive, and lacking in product differentiation. The lack of antibiotic product differentiation is traced to theusage of

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non-inferiorityclinical trial designs that is common practice for most of the antibiotics that have been marketed to date. No new class of antibiotic has been introduced to the market within the lasttwo decades, which further heightens the need for new anti-infectives. In addition to significant market differentiation, mAbs may offer substantially less market competition, and higher barrier toentry. Unlike antibiotics, mAbs have a more predictable and attractive safety profile and are designed to kill via an immunological mechanism of action that is different from the mechanisms of actionof all antibiotics and mechanisms of antibiotic resistance. Therefore, so long as it binds to such bacteria or their toxins, mAbs are likely unaffected by the rise in antibiotic resistant bacteria andwill remain effective against antibiotic resistant bacteria. mAbs also have a dosing frequency of once or twice a month and may require only a single administration for treatment of hospital acquiredpneumonia. Our mAbs will be used as an adjunct therapy in combination with antibiotics, so they will not directly compete with antibiotics. By improving the outcome in terms of mortality and reducingthe time to clinical cure and length of hospital and ICU stay, mAbs offer both a medical benefit to the patient and an economic benefit to the hospital. Our clinical study designs utilize superiorityin primary end points, which will allow for clear demonstration of measureable clinical benefits and product differentiation.

        Weare initially focused on respiratory infections in the ICU settings, particularly bacterial pneumonia caused by agents that have approximate prevalence as shown in Figure 2. Inthe U.S., there are approximately 628,000 cases of HAP and VAP (DRG 2016). HAP due to methicillin-resistant Staphylococcus aureus, or MRSA, infectionsresults in substantial loss of life with an annual worldwide incidence of approximately 200,000 patients (Decision Resources, 2016 data) and mortality rates as high as 50% depending on the patientpopulation and treatment regimen (Methicillin-Resistant Staphylococcus Aureus, Decision Resources, 2016). Mechanical Ventilation for VAP patients costs over $30 billion annually in the U.S. Infectionsdue to MRSA represent a high-value segment of the overall antibiotics market. According to this report, the worldwide market for existing therapies for MRSA infections was over $800 million in2015. The progressively aging population is expected to increase the number of MRSA infections that resultin HAP. Moreover, MRSA infections are associated with significantly longer hospital stays, repeated hospitalizations and increased healthcare costs. Currently, the median hospital stay of a patientwith VAP is 29 days, and the average length of ICU stay is 19 days. The median total hospitalization costs for a VAP patient is approximately $198,000. Current SOC antibiotics for MRSApneumonia is dominated by five antibiotics Linezolid, Daptomycin, Vancomycin, Ceftaroline and Tigecycline, which combined have approximately 90% market share. There is a significant need for newanti-MRSA agents given the S. aureus resistance rate of 31% to 53%. We believe that the addition of AR-301 to SOC antibiotics has the potential toimprove clinical outcome and could be effective in patients with MRSA infections.

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Figure 2
Most Common Bacterial Pathogens in ICU Pneumonia

Figure 3
Potential Addressable Patient Population of our mAbs

        Pseudomonasinfection is caused by strains of bacteria found widely in the environment. P. aeruginosa is one of the most commongram-negative bacteria that is associated with a number of human infections. Drugs targeting gram-negative bacteria must cross both the inner and outer membranes of the bacterial cell, as compared tothose directed against gram-positive bacteria, which must only cross one cell membrane. As a result, gram-negative bacteria tend to be more resistant to antibiotics and the body's own immune system.

        Serious Pseudomonas infections usually occur in people in the hospital and/or with weakened immune systems. Patients in hospitals,especially those on breathing machines, those with devices such as catheters, and patients with wounds from surgery or from burns are potentially at risk for serious, life-threatening infections.Infections of the blood, pneumonia and infections following surgery can lead to severe illness and death. Pseudomonas infections are generally treatedwith antibiotics. Unfortunately, in hospitalized patients, Pseudomonas infections, such as those caused by many other hospital bacteria, are becomingmore difficult to treat because of increasing antibiotic resistance. Multidrug-resistant Pseudomonas can be deadly for patients in critical care.

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Figure 3shows the potential addressable patient population of our three clinical candidates in the US, Europe and Japan (DRG 2016 epidemiological data). According to the Centers for DiseaseControl and Prevention, or CDC, an estimated 51,000 healthcare-associated P. aeruginosa infections occur in the U.S. each year. More than 6,000, or 13%,of these are multidrug-resistant, leading to roughly 400 deaths per year. Multidrug-resistant Pseudomonas was given a threat level of "serious threat"in the CDC's report in 2013 titled, Antibiotic Resistance Threats in the United States.

        Cephalosporinand beta lactamases are the most commonly prescribed first line therapy to treat P. aeruginosa pneumonia, but these drugshave a resistance rate of approximately 30%. The lack of new anti-infective agents and the difficulty of developing new anti-infectives to gram-negative pathogens such as P.aeruginosa has been a public health challenge (Gram Negative Infections, Decision Resources, 2009). Unfortunately, many of the new anti-infectives currently in development aremodifications of existing antibiotics, which likely will be susceptible to resistance through the same mechanisms as current therapies. The need is especially acute for P.aeruginosa, which harbors multi-drug resistant plasmids and is the target of few new drugs under development. As is the case with HAP caused by S.aureus, there is substantial mortality associated with HAP caused by P. aeruginosa and an annual worldwide incidence ofapproximately 450,000 patients (Gram Negative Infections, Decision Resources, 2009). This report estimated the worldwide market for existing therapies for HAP due to Gram-negative infections to be$2.0 billion in 2016 and projected it to increase to $3.7 billion by 2026. Additionally, the markets for lung andblood-born infection such as sepsis are characterized by patients who either have a disruption of the normal protective barrier to infection or have an underlying chronic disease such as cysticfibrosis, non-cystic fibrosis bronchiectasis and chronic obstructive pulmonary disease, or COPD, that leaves the lungs and systemic organs in a weakened state and susceptible to infections by P. aeruginosa.

Cystic Fibrosis with Pseudomonas aeruginosa Infection

        There are more than 70,000 patients with cystic fibrosis worldwide. 80% of these patients present with chronic polymicrobial infections,particularly P. aeruginosa infection. We believe the medical need and market potential for an anti-infective therapeutic that can be given to cysticfibrosis patients chronically is substantial. The current market for inhaled antimicrobials for cystic fibrosis, based on recent combined sales figures for TOBI (tobramycin) and Cayston (aztreonam),is approximately $600 million worldwide. Existing therapies such as aminoglycoside antibiotics lead to a temporary improvement in bacterial load, but ultimately 80% to 95% of cystic fibrosispatients succumb to respiratory failure due to chronic P. aeruginosa infection and airway inflammation. P.aeruginosa is the most significant pathogen, with the majority of cystic fibrosis patients becoming chronically infected by the age of 18 years.

Our Product Candidates

        mAbs represent a fundamentally new immunologic approach for treating bacterial infections that can potentially overcome the problems of toxicityand resistance that may occur with traditional antibiotics when they are used long-term in individual patients and pervasively across patient populations. Our product portfolio consists of candidatesthat have novel mechanisms of action that differ from that of traditional antibiotics and includes five mAb programs, most are discovered using our MabIgX platform technology, and one broad spectrumsmall molecule anti-infective.

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AR-301

        Our lead product candidate, AR-301 is a fully human mAb of IgG1, for the treatment of lung infections resulting from S.aureus including MRSA strains. We are developing AR-301 as an adjunctive therapy with SOC antibiotics to treat HAP and VAP, which is in contrast to other mAb programs currentlyunder development for prevention of HAP and VAP. AR-301 was discovered by screening the B-cell immune response repertoire generated against S. aureusinfection. It has received Fast-Track designation in the U.S., Orphan status in the EU and is ready to advance into a Phase 3 pivotal trial.

        Werecently completed a Phase 2a clinical trial with AR-301 plus SOC antibiotics compared to SOC antibiotics alone to treat HAP and VAP caused by S.aureus. AR-301 is targeted against S. aureus alphatoxin, which is a toxin produced by most S.aureus strains to cause destruction of human cells and tissues, and in mouse models is thus effective against S. aureusinfections whether or not the bacteria are resistant to conventional antibiotics. We believe AR-301 has the potential to positively impact the outcome of S.aureus infections in patients by improving survival rates and/or shortening the duration of overall hospital stays, the length of time a patient requires mechanicalventilation, or the time a patient spends in the ICU.

Background and Mechanism of Action

        AR-301 was discovered by screening B-cell lymphocytes from a patient with a confirmed S. aureusinfection. AR-301 binds to alphatoxin with high affinity and prevents its assembly into an active complex, which prevents alphatoxin-mediated breakdown of cell membranes, or lysis, of erythrocytes,human lung cells and immune cells such as lymphocytes (see Figure 4 below). This prevention of killing of host cells, in turn, may protect the patient from further progression of pneumonia disease andsystemic infections caused by S. aureus. During infection and active proliferation, S. aureus ismetabolically more virulent, geared toward higher toxin production than during its more sessile colonization stage. In contrast to other programs targeting S.aureus colonization, AR-301 targets the active, disease causing infection stage. There is no commercially available product that specifically neutralizes the pathogeniceffects brought about by S. aureus toxins. We believe that this mechanism of action complements the bacterial killing properties of many conventionalantibiotics, essentially neutralizing the bacterial toxins left behind following antibiotic-mediated killing. Additional indications for AR-301 may include any S.aureus infection, particularly surgical site infections, blood stream infections, endocarditis, and skin and soft tissue infections such as diabetic ulcers andnon-healing wounds.

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Figure 4
AR-301's Mechanism of Action

Clinical Development Summary.

        We recently completed a randomized, double-blind, placebo-controlled, active comparator, ascending dose Phase 2a clinical trial to assessthe safety, tolerability, pharmacokinetics, efficacy and pharmacodynamics of a single intravenous administration of AR-301 plus SOC in patients with severe pneumonia caused by S. aureus (Francois, B.et al., 2018. Intensive Care Medicine journal, in-press). The SOC regimens were the physicians' choice and were based on the individual clinical site'sprescribing practice. Forty eight patients wereenrolled in the study. Six patients enrolled in the first cohort (1 mg/kg AR-301 plus SOC), eight in the second cohort (3 mg/kg AR-301 plus SOC), ten in the third cohort (10 mg/kg AR-301 plus SOC) andeight in the fourth cohort (20 mg/kg AR-301 plus SOC). An additional 16 patients received placebo plus SOC as an active control. This Phase 2a clinical trial included 31 sites located acrossBelgium, France, Spain, the United Kingdom, and the U.S. and was designed primarily to address the safety and pharmacokinetics of AR-301. The drug was generally well tolerated. In exploratory analysisof the VAP subgroup of 25 patients, numeric clinical improvement of antibody treated patients over placebo were observed in time to extubation. Additionally, patients treated with AR-301 exhibitedtrends toward a higher rate of microbiological eradication, and reduction in number of hospital or ICU days.

Phase 2a Safety and Pharmacokinetics.

        Data from the Phase 2a clinical trial suggest that AR-301 was well tolerated as a treatment for severe pneumonia due to S. aureuswhen used as directed and in addition to antibiotics. Few (2.8%) adverse events, or AEs, and no SAEs were deemed related to AR-301 treatment.A total of 36 SAEs were observed, which are listed as follows: septic shock (3 patients or approximately 6.3% of patients), anaemia (3 patients), bacteraemia (2 patients orapproximately 4.2% of patients), sepsis (2 patients), acute respiratory failure (2 patients), hypoxia (2 patients), pancreatic abscess (1 patient or approximately 2.1% ofpatients), pneumonia (1 patient), carbon dioxide increase (1 patient), gamma-glutamyltransferase increase (1 patient), platelet count increase

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(1 patient),abnormal prothrombin level (1 patient), duodenal ulcer (1 patient), epistaxis (1 patient), hypoventilation (1 patient), pleurisy(1 patient), pulmonary embolism (1 patient), haemodynamic instability (1 patient), hypotension (1 patient), shock haemorrhagic (1 patient), superior vena cavasyndrome (1 patient), vena cava thrombosis (1 patient), cardiac arrest (1 patient), coronary artery stenosis (1 patient), ventricular tachycardia (1 patient),multi-organ failure (1 patient), pyrexia (1 patient), hepatic failure (1 patient), hepatocellular injury (1 patient), hypoalbuminaemia (1 patient), malnutrition(1 patient), heparin-induced thrombocytopenia (1 patient), coma (1 patient), peripheral motor neuropathy (1 patient), renal failure acute (1 patient), renal failurechronic (1 patient), renal tubular necrosis (1 patient), post procedural haemorrhage (1 patient) and subdural haematoma (1 patient). Immunogenicity was observed in onesubject, with no related adverse event. No significant difference in mortality was observed between groups. There were six deaths in the trial, none of which were deemed related to AR-301.Furthermore, the overall mortality observed (8.5%) in this small sample size study was very low when compared to historic published references. The pharmacokinetic, or PK, profile of AR-301 isconsistent with that of a human IgG1mAb, with a plasma half-life of 23 to 31 days, and supports a single-dose administration for the pneumonia indication (Figure 5).

Figure 5
Pharmacokinetics Profile of AR-301

Phase 2a clinical Efficacy.

        We assessed multiple endpoints of clinical improvement including time to extubation. Time intubated to day 28 showed a decrease in the length oftime patients who were treated with AR-301 plus SOC remained intubated as compared to those receiving placebo and SOC. When the subset of 25 patients with VAP was assessed, a Kaplan-Meyer analysis oftime to extubation showed a separation of the group of patients treated with AR-301 plus SOC as compared to those treated with placebo plus SOC (see Figure 6). In the same subgroup of VAPpatients, ventilation

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timewas reduced numerically for patients in all four active dose groups receiving AR-301 plus SOC compared to those receiving placebo plus SOC. In an exploratory analysis, with all four treatedcohorts pooled and compared versus the placebo cohort, statistical significance was achieved at p<0.01. The lack of dose response could be attributed to high variability associated witha small sample size, and/or to the high level of circulating AR-301 mAbas compared to alphatoxin load in infected patients, i.e. even at the lowest dose administered (i.e. one mg/kg) it is estimated that there is more than ten-fold mAbs than the predictedalphatoxin load.

Figure 6
Impact Adjunctive AR-301 Treatment on Mechanical Ventilation Time (VAP subgroup)

        Wealso determined microbiological outcomes in the overall study population. Eradication or presumed eradication (cured of pneumonia) was observed in 25 (78.1%) patients treated withAR-301 plus SOC and ten (62.5%) of 16 subjects treated with placebo plus SOC. Details of microbiologial outcome by treatment cohort are provided in Figure 7a and the mean time to eradication of S. aureus bacteria also trended shorter in AR-301 treated cohorts as compared to the Placebo cohort (Figure 7b).

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Figure 7a
Summary of Microbiological Outcome by Dose Level

Figure 7b
Mean Time to Microbiological Eradication

        Whenclinical cure was assessed based on the sole judgment of the investigator, there was no statistically significant difference between the groups, and the overall cure rate was highcompared to historic published references. Over the first 28 days of the study, the length of stay in the ICU and in the hospital both showed a modest decrease in the AR-301 plus SOC groups ascompared to placebo plus SOC-treated subjects, however, this difference did not reach statistical significance.

        AlthoughSOC antibiotics were effective, the results suggest that the addition of AR-301 to SOC treatment may increase the rate of microbiological eradication, and may reduce time toeradication, time under mechanical ventilation and overall duration of hospital stay. Time ventilated in the pooled AR-301 treated cohorts (n=20) showed an exploratory p<0.01 reduction in the subsetof patients with VAP as compared to the placebo plus SOC cohort (n=5).

Preclinical Summary

        In vitro studies demonstrated the selective binding of AR-301 to alphatoxin as well as theability of AR-301 to neutralize toxin effects on several cell models. Antigen specificity and alphatoxin binding were confirmed by performing binding assays using purified bacterial toxins from variedsources including bacterial cell supernatants of the most prevalent epidemic MRSA strains worldwide, and bacterial cell supernatants of an extensive panel of MRSA and methicillin sensitive S. aureus, orMSSA, clinical isolates. AR-301 was shown to bind to greater than 95% of all S. aureusclinical isolates tested (more than 110 tested).

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        Preclinicaltesting in an experimental acute S. aureus pneumonia mouse model and sepsis model showed that AR-301 can be used asprophylactic to prevent infection-associated morbidity and mortality or as a therapeutic when delivered intravenously as a stand-alone treatment. For example, in the prophylactic murine lung infectionmodel (see Figure 8), we evaluated the ability of AR-301 to protect against disease. Groups of 15 mice received an intraperitoneal injection of either isotype control antibody (human IgG1) orAR-301 two hours prior to the time of intranasal infection with bacterial strains of interest and were then monitored over 72 hours for lethal disease. The studies were conducted with threedistinct S. aureus strains, including Newman, a methicillin-sensitive clinical isolate that maintains a stable virulence phenotype in thelaboratory, USA100, a methicillin-resistant hospital isolate, and USA300/LAC, a methicillin-resistant epidemic clone that is the most widely circulated MRSA strain in the U.S. As demonstrated inFigure 8, AR-301 conferred in a dose-dependent manner significant protection against mortality induced by an acute infection with Newman (A), USA100 (B) and USA300 (C).

Figure 8
Effect of AR-301 in Prophylactic S. aureus Pneumonia Model

        Intherapeutic mouse pneumonia studies, AR-301 demonstrated protection against death caused by either the MSSA strain Newman (Figure 9A) or the MRSA strain USA100(Figure 9B), even when AR-301 was applied up to several hours post infection. Overall, protection decreased (mortality increased) in the groups with later antibody application and withduration of the observation period, thereby suggesting that alphatoxin may be essential, particularly during the early stage of pathogenesis. We believe an extrapolation of these findings to humandisease implies that treatment with AR-301 early in the course of S. aureus pneumonia has the potential to delay

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diseaseprogression, providing a much-needed window of opportunity to enhance the utility of antimicrobial and supportive therapies.

Figure 9
Effect of AR-301 in Therapeutic S. aureus Pneumonia Model

        Administrationof AR-301 mediates protection in a therapeutic S. aureus pneumonia model. Mice were treated with AR-301 two hours prior tointranasal infection or four hours, eight hours, and 12 hours post challenge. For both bacterial MSSA (A) and MRSA (B) isolates tested, a significant decrease in 48 hoursmortality was observed for antibody applications up to 12 hours post infection. Statistical significance (p<0.05) is indicated in Figure 9 by an asterisk.

        Tounderstand the mechanism by which lethal disease was averted by AR-301, bacterial loads in the lungs of mice treated with isotype control IgG1 or AR-301 were assessed 24 hourspost-infection. Treatment of mice with isotype control IgG1 antibody or AR-301 two hours prior to the time of infection at a concentration of ten mg/kg each leads to a marked reduction in S. aureusburden in the lungs. Importantly, this reduction in bacterial load was apparent upon infection with MSSA strain Newman (A) andboth hospital-acquired MRSA strain US100 (B) and community-acquired MRSA strain US300 (C). The horizontal bars indicate the mean bacterial load. (see Figure 10). These datasupport the hypothesis that by neutralizing alphatoxin, AR-301 may mitigate alphatoxin-mediated killing of immune cells, thereby preserving the immune system's natural ability to reduce bacterialburden.

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Figure 10
Effect of AR-301 on Lung Bacterial Load in a S. aureus Pneumonia Model

        Collectively,the above preclinical animal infection and treatment studies suggested that treatment with AR-301 resulted in improvement in resolution of disease, and further suggestedthat neutralizing alphatoxin was necessary and sufficient to confer protection against morbidity and mortality.

        Thetoxicology program for AR-301 determined that there was no toxicity in the dose-range pilot study and the repeat-dose toxicity study performed in mice. Further, no treatment-relatedmicroscopic changes at the injection sites were observed, thereby confirming good local tolerance of AR-301.

Planned Development Activities

        We plan to conduct two pivotal clinical trials in pneumonia patients for regulatory approval in the U.S. and Europe. We had an end ofPhase 2 meeting with the FDA in June 2017 on the two proposed primary efficacy endpoints, ventilation time and clinical cure, for these two Phase 3 clinical trials. We also submitted abriefing document and received feedback from a EMA's Scientific Advice experts in January 2018. We are currently in negotiations with the FDA and EMA on these endpoints, or a consolidated singleprimary endpoint, which may include the components of mortality, ventilation requirements and signs and symptoms of pneumonia. Per discussions with clinical experts in the field, >15%improvement of AR-301 plus SOC over placebo plus SOC on these efficacy outcomes is deemed to be clinically meaningful. The first Phase 3 clinical trial will be a randomized, double-blind,placebo-controlled active comparator AR-301 (20 mg/kg) plus SOC versus placebo plus SOC. We plan to enroll approximately 210 VAP microbiologically evaluable patients at approximately 125clinical sites in over 15 countries. Assuming a treatment effect of clinical cure of 85% versus 65% in active drug treated patients would provide 90% power to demonstrate a statistically significantresult. We also reached agreement with the FDA on the size of the safety database required for approval and we plan to include the following safety endpoints: immunogenicity, adverse events, andstandard safety laboratory tests. We expect to enroll the first subject in the second half of 2018, plan to include an interim data readout in the second half of 2019, and complete enrollment by thefirst half of 2020.

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AR-105

        AR-105 is a broadly active fully human IgG1 mAb targeting P. aeruginosa alginate, a widelydistributed cell surface polysaccharide involved in surface adhesion, biofilm formation, and protection against the human immune system. We found that it was expressed in over 90% of P. aeruginosaclinical isolates from pneumonia patients suggesting the potential for broad coverage. In addition, alginate is highly conserved and wehave not identified any escape mutants to date. We believe that AR-105 plus combinations of antibiotics may be beneficial to the overall therapeutic efficacy of treatment regimens because P. aeruginosais a problematic, difficult-to-treat bacterium that often requires a combination of antibiotics to effectively treat.

        Anincreasing concern with P. aeruginosa infections is the increasing incidence of multi-drug resistant hospital associated lunginfections, including HAP and VAP, occurring in patients on mechanical ventilators. It is estimated that the addressable patient population in the United States, EU and Japan combined is approximately478,000 patients. As a result, we are developing AR-105 plus SOC antibiotics as an adjunctive therapy to treat HAP and VAP. AR-105 was shown to be well tolerated in the recently completedPhase 1 clinical trial in healthy volunteers. We are currently in a global Phase 2 clinical study with this product candidate and project data readout in the first half of 2019.

        Alginateproduction is a hallmark of chronic P. aeruginosa infection and progressive decline in lung function in patients with cysticfibrosis. As a result, we believe that AR-105 can potentially be developed as a therapy to treat P. aeruginosa infection in cystic fibrosis patients. Weplan to explore the mAb utility in this indication in the future.

Background and Mechanism of Action

        AR-105 specifically binds to P. aeruginosa alginate expressed on the cell surface of P. aeruginosa. AR-105 binding activates the C3b component of the complement system, a part of the immune system which binds to the bacterial cellwall in a process called antibody opsonization. The cell surface bound antibody and C3b are then recognized by receptors on the cell surface of immune cells called polymorphonuclear leukocytes, whichresults in the phagocytosis, or ingestion, and killing of the bacterial cell (see Figure 11).

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Figure 11
Mechanism of Action of AR-105 mAb

Clinical Development Summary

        We recently completed an open-label, single ascending dose Phase 1 clinical trial of AR-105 in which all subjects received oneintravenous dose of AR-105. The trial consisted of three dose cohorts of AR-105 with safety and pharmacokinetics outcome as shown in Figure 12. Cohort one received two mg/kg of AR-105 (n=fivesubjects), cohort two received eight mg/kg of AR-105 (n=six subjects), and cohort three received 20 mg/kg of AR-105 (n=five subjects). The dose levels for the study were selected based on animalstudies showing prophylactic and therapeutic effects in a pneumonia animal model and toxicological studies. The results showed that AR-105 was well tolerated at all dose levels tested, with no SAEsobserved, and a total of 14 AEs that were deemed to be non-remarkable and typical of mAb infusion (e.g. infusion site edema, headache, etc.). Furthermore, the PK profile of AR-105 wasfound to be consistent with the known PK profiles of IgG1 mAbs.

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Figure 12
Summary of AR-105 Phase 1 Study

Preclinical Activity Summary

        In in vitro studies, AR-105 demonstrated the ability to bind to and kill a wide range (greaterthan 90%) of P. aeruginosa clinical isolates from pneumonia patients through opsonic phagocytosis. These clinical isolates included P. aeruginosa strainswith varying levels of antibiotic resistance to TOBI (tobramycin) and Cayston (aztreonam) suggesting that AR-105's activity isindependent of the antibiotic resistance status of a given P. aeruginosa strain.

        Severalpreclinical animal models have demonstrated the protective activity of AR-105 treatment against P. aeruginosa infections. AR-105prevented both morbidity and mortality resulting from infection when administered intravenously either prophylactically or therapeutically in an acute P.aeruginosa pneumonia mouse model. AR-105 had a synergistic effect when combined with antibiotics tobramycin (Figure 13 Left Panel) or meropenem (Figure 13 Right Panel) in P. aeruginosa infected mice exhibiting severe pneumonia (Figure 13).

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Figure 13
Synergistic Protection of P. aeruginosa Infected Mice Using AR-105 and Antibiotic Tobramycin (left) or Meropenem (right)

        Inthe study depicted above, infected mice were treated with sub-protective dose levels of AR-105 (0.01 and 0.04 mg/kg, once via nasal administration) and either tobramycin or meropenem(1.4 and 0.8 mg/kg, respectively, daily via intravenous administration) separately and in combination, followed by assessment of lung bacterial load (measured as colony forming units, or CFUs) at T=0and 24 hours post-drug treatments. The combination of AR-105 and tobramycin or meropenem showed lower bacterial load than either treatment individually.

        Therapeuticprotection by AR-105 was also demonstrated in a mouse model of sepsis where the infection was initiated by an intraperitoneal injection of P.aeruginosa followed by an intraperitoneal injection with escalating doses of AR-105 four hours later. Treatment with AR-105 resulted in protection from the lethality of the P. aeruginosa infection. Increasing doses of AR-105 resulted in increased protection. Collectively, the results of these preclinical studiesdemonstratedthat AR-105 is highly effective in mice in attenuating pulmonary and septic infections caused by P. aeruginosa.

Planned Development Activities

        We initiated a Phase 2 clinical trial in VAP patients on mechanical ventilation in the second quarter of 2017. This trial is arandomized, double-blind, active comparator trial with a single dose of AR-105 (20 mg/kg) plus SOC antibiotics or placebo plus SOC antibiotics. This study is being conducted at approximately 90 sitesin fourteen countries, in the U.S., EU and Asia. This study is

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designedto detect superiority in the primary endpoint of clinical cure rate on day 14 at p-value of 0.05.

AR-101

        AR-101 is a human IgM mAb that we are developing to treat P. aeruginosa, the leading cause ofhospital acquired lung infections. AR-101, which we are initially developing as an adjunct therapy for the treatment of HAP and VAP caused by P.aeruginosa serotype O11, binds to the lipopolysaccharide, or LPS, on the cell surface of P. aeruginosa. Serotype O11 isone of the most prevalent P. aeruginosa serotypes in HAP and VAP, representing approximately 23% of cases (Lu et al 2014). It is estimated thatthe addressable patient population in the U.S., EU and Japan combined is approximately 95,600 patients. AR-101 has been granted orphan drug designation in the U.S. and in the EU. We intend toincorporate a companion diagnostic test based on polymerase chain reaction, or PCR, technology that can rapidly identify P. aeruginosa serotype O11strains in order to identify those patients most likely to respond to AR-101. We have completed a Phase 1 safety and tolerability trial of single ascending doses of AR-101 in healthy adults andan open-label Phase 2a safety and pharmacokinetics trial of up to three single doses ofAR-101 in pneumonia patients. These studies suggested AR-101 to be generally well tolerated in both healthy adults and HAP and VAP patients. Comparison of the per protocol population (n=13) of thePhase 2a study, which excluded four patients from the ITT population (n=17) because they did not complete the treatment regimen, and a contemporaneous control cohort suggested that AR-101therapy may improve survival, cure rate of the index pneumonia, and time to cure pneumonia.

Figure 14.
AR-101 Mechanism of Action

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Background and Mechanism of Action

        Upon binding, AR-101 mediates the deposition of the human complement to the surface of P. aeruginosa bacteria. Thisantibody-complement complex leads to improved recognition by the host immune cells, which results in engulfment andkilling of the bacteria (Figure 14). AR-101, like IgM antibodies in general, provides several advantages towards more effective bacterial killing. They possess ten binding sites rather than two forIgG, and they are 100 to 1,000 times more effective than IgG at binding and/or activating key enzymes that facilitate thekilling of P. aeruginosa. As a result, IgM antibodies are becoming more prevalent as candidates for drug therapies.

Clinical Development Summary

        We have completed two clinical studies of AR-101 to date. We completed a Phase 1 study in healthy volunteers to assess the safety andpharmacokinetic characteristics of AR-101. This randomized, double-blind, placebo-controlled study enrolled 32 volunteers in four antibody treatment cohorts at doses of 0.1, 0.4, 1.2 and 4.0 mg/kg aswell as placebo cohort. No SAEs were observed, and no subject was discontinued due to an AE. Reported AEs were mild or moderate in intensity, and all resolved without sequelae, and the incidence ofAEs did not increase with the dose. There was no activation of an immune response against AR-101. Pharmacokinetic characteristics that were observed were consistent with the characteristics of a humanIgM, with a serum half-life between 70 and 95 hours.

        Subsequently,we completed an open-label Phase 2a study in 18 subjects, which was the first study performed in the target indication of patients with severe bacterial pneumoniacaused by P. aeruginosa serotype O11. Treatment consisted of three intravenous infusions of 1.2 mg/kg of AR-101 given over two hours on days one,four and seven for a total dose of 3.6 mg/kg. The 30-day survival rates were 82% and 100% in the intent-to-treat (ITT; 17 subjects) and the per protocol (13 subjects) populations, respectively.Clinical resolution of pneumonia was observed in 76% of patients in the ITT population and 100% of patients in the per protocol population. Microbiological resolution was observed in six subjects,representing 35% of the ITT population and 31% of the per protocol population. The time to resolution of pneumonia was 14 days and nine days in the ITT and per protocol populations,respectively. The time to extubation or cessation of ICU management was 22 days in the ITT and 13 days in the per protocol populations, respectively. Measurements of clinical statusimproved promptly in parallel with clinical resolution of disease.

        14SAEs were experienced by six of the subjects. The types of SAEs were: gastrointestinal bleeding (3 patients or approximately 21% of patients), cardiac and respiratory arrest(2 patients or approximately 14% of patients), multi-organ failure (2 patients), hyperbilirubinemia and cholestasis (1 patient or approximately 7% of patients), neutropenia(1 patient), low count of platelets (1 patient), activated partial thromboplastin time (1 patient), prolongation (1 patient), septic shock (1 patient); cholestasis(1 patient) and troponin increase (due to cardiac arrest) (1 patient). An event of cardiorespiratory arrest was judged as probably related to AR-101 and events of hyperbilirubinemia andcholestasis, although pre-existent, were deemed possibly related. In both cases, the investigators assessed that a contribution by AR-101 to the adverse event could not beexcluded with certainty but acknowledged other probable causes were acknowledged. The other SAEs were deemed unrelated.

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        Inparallel, we also conducted a contemporaneous cohort study of the incidence and outcome of HAP and VAP caused by various P. aeruginosaserotypes in critically ill patients. The data were extracted from the medical files of the patients selected according to eligibility criteria similar to those of our Phase 2a study. Cohortpatients infected with P. aeruginosa serotype O11 (14 patients in total) had a lower survival rate, cure rate, and microbiological resolution rate, aswell as longer mean times on ventilator and in the ICU as compared to patients in our Phase 2a clinical trial who received a complete treatment of three 1.2 mg/kg doses of AR-101. A summary ofthe results of the Phase 2a study and the contemporaneous cohort study is shown in Figure 15 below.

Figure 15
AR-101 Phase 2 Trial Comparison of Adjunctive (AR-101 + Antibiotics)
to Cohort (Antibiotics Alone) Groups

Preclinical Summary

        AR-101 reacts with a wide range of P. aeruginosa serotype O11 clinical isolates from differenthospitals, indicating broad application against infections with this serotype. AR-101 is also capable of stimulating phagocytic immune cells to ingest P.aeruginosa bacterial cells in a dose dependent manner, thereby killing the pathogen. Passive immunization with murine mAb recognizing O-polysaccharides in LPS of P. aeruginosa conferred protection against lethal challenge with live pseudomonas bacteria in several animal models of pneumonia infections. Inpreclinical studies, AR-101 was found to demonstrate attenuating protection against pulmonary infections caused by P. aeruginosa serotype O11 andexhibited a complementary effect with meropenem, a broad-spectrum antibiotic. Additionally, we had the following observations in preclinical studies of AR-101. AR-101 protected mice in adose-dependent manner from P. aeruginosa infection after a burn-wound challenge. Doses of five mg/mouse(corresponding to about 0.2 mg/kg body weight) conferred 70% to 100% protection from systemic P. aeruginosa challenge.Administration of decreasing doses resulted in lower survival rates and administration of AR-101 led to rapid clearance of P. aeruginosa from thelung in mice and was associated with milder lung pathology six

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and24 hours after infection. In addition, AR-101-treated animals had a significantly lower systemic P. aeruginosa bacterial load compared tocontrol animals that received saline. To mimic the adjunctive use of AR-101 in humans, AR-101 was administered in combination with meropenem (used clinically to treat pseudomonal infections) in amodified lung challenge model. When meropenem and AR-101 were administered in combination, significant reductions in lung weight (a surrogate marker for injection-induced inflammation), bacterial loadand lung inflammation were observed in infected mice compared to each agent given alone.

Planned Development Activities

        We plan to initiate a double-blind, randomized, placebo-controlled Phase 2/3 clinical trial as an adjunct to SOC antibiotics H2 of 2019.The clinical trial will enroll adult patients with HAP or VAP. As with the prior Phase 2a study, the primary efficacy endpoint in this study will include clinical cure rate. Time to clinicalcure was an endpoint that achieved statistical significance in the Phase 2a study (p=0.005) and will be evaluated in detail in thePhase 2/3 study. We will also assess microbiological endpoints as well as select pharmacoeconomic endpoints and pharmacokinetics.

AR-201

        We have obtained a high affinity anti-RSV F-protein mAb, which we refer to as AR-201. RSV is the leading cause of lower respiratory tractillness in infants and young children worldwide. In premature neonates, RSV infection results in high levels of morbidity. In the U.S. alone, there are more than 234,000 hospitalizations and 14,000deaths per yearattributable to RSV. The only prophylaxis for RSV is Synagis (palivizumab), a humanized murine mAb that targets the RSV glycoprotein F and has been shown to reduce the rate of RSV-associatedhospitalization by 50%. Synagis-resistant RSV strains are rising, which emphasize the need for additional anti-RSV products against different epitopes. Tonsils of RSV-infected patients were used as aB-cell source for screening new antibody candidates with improved activity against RSV F-protein.

        Comparedto Synagis, AR-201 has higher affinity for F protein (700 pM versus 60 pM) and superior in vitro neutralization activity. AR-201was found to bind to naturally occurring Synagis-resistant strains. AR-201's epitope is distinct from that of Synagis, and as a result, can potently neutralize Synagis-resistant isolates. Preliminarycotton rat testing demonstrates that AR-201 provides comparable protection to Synagis in this animal model. We intend to develop AR-201 for the prevention of RSV in neonates and in additionalhigh-risk patients. As part of a recent NIH Small Business Innovation Research, or SBIR, award, we are using recombinant approaches to extend the half-life of AR-201 to create a potential foronce-a-season dosing, which we believe will provide opportunities for introduction of anti-RSV prophylaxis into worldwide markets that are not served by the existing Synagis product.

AR-401

        AR-401 is our mAb discovery program aimed at treating infections caused by A. baumannii, whichis a gram-negative pathogen that is rapidly emerging as a serious threat to patients in hospital care. Its high level of resistance to first-line antibiotic therapies, potential to survive prolongedperiods on dry surfaces and ability to form biofilms rapidly on artificial devices, such as catheters and ventilators, have made it particularly virulent. The clinical impact of A. baumannii

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infectionscan have serious adverse consequences with crude mortality rates reaching 30% in infected ICU patients. Moreover, infection with A. baumanniileads to an increased length of stay at the ICU of an average of 15 extra days. We intend to develop an anti-A. baumannii human mAb to address the unmetmedical need for new and effective anti-infectives to treat severe and life-threatening infections caused by this difficult-to-treat bacterium.

        Wehave made significant progress toward the identification of potential anti-microbial targets on A. baumannii, which we believe willfacilitate the development of both active and passive immune-based therapies. We believe our preliminary target identification work on A. baumannii isamong the most comprehensive to date. We used a proteomic approach to identify bacterial surface proteins that are accessible to the immune system. We then performed a thorough analysis using multiplebioinformatic tools that reduced the number of identified proteins to eight outer membrane proteins on A. baumannii. Our studies showed that activeimmunization with each protein reduced mortality in a pneumonia model. Antibodies against these A. baumannii targets were also detected in the majorityof A. baumannii infected patient sera. Polyclonal rabbit immune sera raised against these targets mediated protection in the Acinetobacter pneumonia mousemodel as shown by a reduction of mortality and clinical score.

        Ofthe eight surface proteins identified as potential targets for mAbs, three have been previously characterized. The five remaining proteins are of unknown function, potentiallyrepresenting completely unique and innovative targets. Antibody titers to all eight proteins can be detected in sera of convalescent patients whereas sera from healthy donors from a regional bloodbank have only very low or undetectable antibody serum titers to these proteins. An initial study demonstrated that the peripheral blood lymphocytes, or PBL, from patients with a high serum titer canresult in hybridoma cell lines that specifically stain A. baumannii cells. Our planned next step for this program is to select a lead therapeutic mAband advance into in vitro potency testing and in vivo assessment of therapeutic efficacy in an A. baumanniichallenge mouse model.

AR-501

        We are developing AR-501 (gallium(III) citrate) as an anti-infective therapy to manage both chronic lung infections in cystic fibrosis patientsand acute pneumonia in HAP and VAP patients AR-501 exhibits broad antimicrobial activity against antibiotic resistant gram-negative and gram-positive bacteria in free-living, or planktonic, andbiofilm communities, as well as against fungi. We believe AR-501's unique combination of broad spectrum antimicrobial activity against pathogens, lower propensity to develop resistance than inhaledTOBI (tobramycin) and Cayston (aztreonam), and less frequent dosing as compared to SOC, make it an ideal candidate for treatment of chronic polymicrobial infections, such as lung infections in cysticfibrosis patients.

        Toenhance delivery to the lungs and provide a simple method of administration, we are developing AR-501 as an inhaled formulation that can be administered conveniently with one ofseveral commercially available liquid nebulization devices. We were recently awarded a development grant from the Cystic Fibrosis Foundation for approximately $3 million to develop anaerosolized formulation of AR-501 to manage bacterial lung infections in cystic fibrosis patients. We have produced, good manufacturing practice, or GMP, clinical bulk drug that is ready for use inhuman clinical trials, and we have completed good laboratory practice, or GLP, toxicology studies. We believe that the unique characteristics of AR-501, namely broad spectrum activity, lowerpropensity to develop resistance, and long half-life, may enable cystic fibrosis patients to

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avoidthe current need for the intermittent "drug holidays" commonly employed with SOC drugs such as TOBI (tobramycin). The unique characteristics of AR-501 may also benefit patients with otherinfectious lung diseases such as chronic obstructive pulmonary disease, bronchiectasis, and pneumonia.

Background and Mechanism of Action

        AR-501 is a proprietary formulation of gallium(III) citrate. Trivalent ions of the element gallium (Ga) have biologic activity because Ga(III)chemically mimics the ferric iron ions (Fe(III)) that bacteria and many other microorganisms require for survival. Bacterial iron-binding proteins imperfectly distinguish Ga(III) from Fe(III),functionally starving bacteria of iron and poisoning critical Fe(III)-dependent metabolic pathways. We believe this unique mechanism of action is distinct from those underlying all currentantibiotics.

        Thereis a long history of administering gallium(III) salts to humans. Gallium scans are used as diagnostic tests to identify areas of inflammation, infection, or cancer in the body, andGanite, a formulation of gallium(III) nitrate, was introduced in 2003 as an FDA-approved intravenous treatment for hypercalcemia secondary to cancer. The anti-infective activity was only recentlydemonstrated using gallium(III) nitrate in citrate buffer. Our in vitro tests and in vivo animal studiesshow that gallium(III) citrate exhibits the same antimicrobial activity as gallium(III) nitrate in citrate buffer, demonstrating that Ga(III) ion itself, and not any particular salt form, isresponsible for the anti-infective activity.

Clinical Data Summary

        More than 50 published human clinical trials conducted in more than 1,000 cancer patients attest to the safety of systemic Ga(III) compounds andestablish a tolerated dose that greatly exceeds the dose at which we project AR-501 will be used. Recently an open-label Phase 1 proof-of-concept clinical trial of Ganite administeredintravenously to cystic fibrosis patients showed evidence of an improvement in lung function and reduction of P. aeruginosa burden in the lungs.Investigators at the University of Washington, or UW, and the Cystic Fibrosis Foundation conducted the clinical study, and we analyzed patient samples to determine pharmacokinetics. The aim of thestudy was to assess the pharmacokinetics, lung distribution, and safety of intravenous Ga(III) in cystic fibrosis patients. This non-randomized Phase 1 study comprised two dosing cohorts(cohort one: n=9 patients, cohort two: n=11 patients). Analysis of subjects' sputum, urine, and plasma showed persistent Ga(III) levels in sputum up to 28 days after a single dose.Encouragingly, a number of patients in both cohorts showed significant reduction in sputum P. aeruginosa and an improvement in steady forcedexpiratory volume (FEV1) throughout the 28 days. We anticipate that inhaled AR-501 can result in at least 100-fold higher Ga(III) concentration in the lungs. The UW investigators continue todevelop Ganite as an intravenous treatment for cystic fibrosis associated lung infections and recently initiated a randomized, double-blind Phase 2 clinical study in cystic fibrosis patients.This study is expected to be completed in the second half of 2018 and may provide additional clinical evidence of the safety and efficacy of Ga(III) in cystic fibrosis patients.

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Preclinical Data Summary

        AR-501 exhibits antimicrobial activity in diverse in vitro and invivo bacterial infection models. The in vitro activity of Ga(III) salts extends to many gram-negative and some gram-positivebacteria, and in vivo activity has been demonstrated against P. aeruginosa when administered viainhalation and intraperitoneal injection. We showed that persistent exposure of P. aeruginosa to gallium(III) citrate did not change the minimuminhibitory concentration, or MIC, whereas parallel studies demonstrated a greater than eight-fold rise in MIC for the antibioticstobramycin, vancomycin, or aztreonam. Thus we believe that for mechanistic reasons, bacteria are less likely to develop resistance to Ga(III) compounds than to conventional antibiotics.Pharmacokinetic studies of inhaled AR-501 in mice showed the initial half-life was 0.6 hours and the terminal half-life was 40.0 hours. In preclinical animal lung infection studies,AR-501 at an inhaled dose as low as 3.7 mg/kg is protective against a lethal challenge with P. aeruginosa strain PA103.

        Wetested the local effects of inhaled Ga(III) on lung tissues by examining the acute pulmonary toxicity of inhaled gallium(III) nitrate formulated in a citrate buffer in mice. Weexposed animals to aerosolized gallium(III) nitrate formulated in a citrate buffer (12.5 mg/mL) for two, four, or six hours in a whole body exposure chamber. Histopathological evaluation revealed nosignificant changes in lung tissues. Inflammation was observed that reached a maximum at four to eight hours post dosing, but waned beyond eight hours. Mice and subsequently dogs that wereadministered AR-501 by inhalation once per week for 28 days (five administrations), showed unremarkable clinical chemistry findings, and no significant adverse observations were noted in thelungs or kidneys. The no observed adverse effect level from the GLP toxicology testing has been established.

Planned Development Activities

        Our AR-501 development program includes toxicity testing in two animal species in accordance with GLP requirements to assess the safety ofAR-501 administered by inhalation. The program includes GLP toxicology studies in mice and dogs, encompassing both single dose and repeated dose administration of AR-501 by inhalation. We plan tosubmit an IND to the FDA in which we propose a two-part, double-blind, randomized, placebo-controlled, ascending dose study to evaluate the safety, tolerability, PK, and respiratory lung functionmeasures following the administration of inhaled AR-501 first in normal healthy adults, then in adult cystic fibrosis patients.

Our MAbIgX Fully Human Antibody Discovery Platform

        Our proprietary MabIgX discovery platform enables us to rapidly screen, identify and optimize fully human therapeutic mAb product candidatesdirectly from the B-cells ofpatients. We have developed a method of selecting rare, potent B-cells isolated either from convalescent individuals who have successfully survived an infection with the pathogen or healthyindividuals who have been actively immunized with a vaccine against a target pathogen. These B-cells produce antibodies that are highly relevant for the body's defense against a particular pathogenand which we believe will be highly protective mAb therapeutic product candidates. Our mAb product candidates are of completely human origin, which we believe maximizes the antibodies' protection andeffector functions and minimizes the risk of adverse reactions. Our MabIgX technology

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platformdoes not require the use of recombinant antibody technologies or any genetic engineering steps that can be time consuming and may be protected by third party intellectual property rights.

        Webelieve our MabIgX drug discovery platform, which enables us to rapidly identify and manufacture naturally occurring fully human antibody product candidates, provides us with thefollowing competitive advantages:

•

ability to rapidly screen for rare and potent B-cells to produce differentiated mAb product candidates and expeditiously progress productcandidates from target identification to clinical development;



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broad applicability to produce immunologically and clinically relevant product candidates across all relevant immunoglobulin isotypes,including IgG, IgA, IgM and IgE antibodies;



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discovery of mAb product candidates with high efficacy due to recognition of epitopes relevant for humans;



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generation of mAb product candidates that are well tolerated and that have the potential for multiple administrations due to lowimmunogenicity, or nominal ability to provoke an anti-drug immune response; and



•

ability to rapidly progress to clinical manufacturing by avoiding the need for time consuming recombinant antibody engineering processes andproduction cell lines.

        OurMabIgX technology platform is summarized in Figure 16.

Figure 16.
MabIgX B-cell Discovery and Manufacturing Process Flow

        Thefirst step in our process is the selection of immunized or convalescent patients who serve as donors for blood collection. We have collaborations with physicians as well asspecialized clinical sites for the selection, recruitment and blood collection of convalescent donors. We also

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haveestablished protocols for the selection of donors and the optimal time for blood collection, both of which depend largely on the targeted infection and the desired isotype of the desired mAb.

        Thenwe apply classical hybridoma technology, whereby the human B-cells of the donors are isolated, transiently immortalized by infection with Epstein-Barr virus, or EBV, andsubsequently fused to the proprietary heteromyeloma cell line LA55 to form stable hybridoma lines. Our technology enables us to overcome one of the major challenges in developing human therapeuticmAbs, which is the inability to easily select and culture antigen-induced mAb-producing human B-cells and to use them to construct continuous mAb-producing cell lines. We have defined the propertiesof circulating antigen-specific human B-cells recruited through the immune response to polysaccharide and protein antigens, and have optimized their enrichment and propagation in culture for theproduction of fully human mAbs. After isolation, these highly antigen-specific human B-cells are immortalized employing LA55, which generates stable hybridomas for large scale manufacturing of ourfully human mAbs.

        Ourtechnology enables us to isolate and select the most relevant and most effective human antibodies for a specific pathogen. Not all pathogens require the same type of immune effectorfunction, and therefore, our immune system has developed a set of different antibody isotypes with very specific characteristics. For example, high-affinity IgG antibodies are more efficient atneutralizing viruses and preventing infections whereas IgM antibodies can more efficiently attack gram-negative bacteria by targeting the bacterial surface polysaccharides and by activatingcomplement, which leads to a "flagging" of the bacteria, known as opsonization, and ultimately the destruction of the bacteria by the immune system. It is important to isolate antibodies of the properisotype based on the infection targeted and the desired reaction of the human immune system. Our MabIgX technology enables the isolation of the isotype of an antibody that the human immune systemutilizes to combat a particular pathogen and isolate all different isotypes. All those antibodies retain their effector function, which is an important factor in the regulation of an effective immunereaction in the human body (see Figure 17).

Figure 17.
MabIgX Technology Allow For Discovery of all Four Naturally Occurring Antibody Types

        Afterisolation, these highly antigen-specific human B-cells are immortalized employing LA55, which generates stable hybridomas for large scale manufacturing of our fully human mAbs.

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Manufacturing

        We do not own or operate manufacturing facilities for the production of clinical or commercial quantities of our product candidates. Wecurrently have no plans to build our own clinical or commercial scale manufacturing capabilities. To meet our projected needs for commercial manufacturing, commercial manufacturing partners will beengaged which have large bioreactors (greater then 2,000L). Although we rely on contract manufacturers, we have personnel with manufacturing experience to oversee our relationships with contractmanufacturers.

        OurMabIgX technology produces a hybridoma cell line that can be used to produce clinical material without any further genetic engineering, which allows us to move rapidly to manufactureclinical material and enter clinical testing. This cell line is used to produce clinical material for our Phase 1 and Phase 2 clinical trials.

        Weare developing production cell lines to support late-stage clinical testing and commercialization based on Chinese hamster ovary, or CHO, cell technology which is the most mature andwidely used cell culture technology for the manufacture of mAb products.

        Wewill then identify and utilize a CMO, that has experience using CHO cells to produce both clinical and commercial biotechnology products under current good manufacturing practices, orcGMP, and that can meet global regulatory requirements. The CHO cell product is typically introduced into clinical testing during the pivotal trial stage once comparability with the hybridoma cellproduct has been established. Our plan is to launch commercial production from the CMO facility and subsequently decide whether we will explore building a Company owned manufacturing facility.

        AR-301.    We have created a new CHO cell line to maximize production quantities and to scale up the manufacturing process. The clinicaldrug productwas manufactured under GMP at 1,000L scale by our contract manufacturing partner Catalent Pharma Solutions (Madison, WI). The manufacturing process will be scaled up to 2,000L scale to supportlicensure and commercial launch.

        AR-105.    A clinical manufacturing scale cell culture and mAb purification process has been developed. The clinical material wasmanufactured by ourcontract manufacturer MassBiologics (Mattapan, MA) at 2,500L scale to support the Phase 2 clinical trial. We have created a new CHO cell line to further maximize production quantities. The CHOline will be used to manufacture clinical trial material for the Phase 3 pivotal trial and support commercial manufacturing.

        AR-101.    A clinical manufacturing scale cell culture and mAb purification process has been developed and transferred to our clinicalmanufacturers,Sanquin Pharmaceutical Services (Amsterdam, The Netherlands) and Rentschler Biotechnologie GmbH (Laupheim, Germany), to produce AR-101 clinical trial material. Additional clinical material willbe needed to support both the Phase 2/3 and Phase 3 clinical trials.

        AR-501.    We have developed a simple manufacturing process to produce pure gallium(III) citrate using gallium(III) nitrate andammoniumcitrate. The manufacturing process was transferred to a contract manufacturer, Regis Technologies, Inc. (Morton Grove, IL) and was implemented at a 10kg scale under GMP. The filling of drugproduct into blow-fill-seal (BFS) ampules under GMP has been completed. We believe this material will be sufficient to support our clinical trial needs.

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Competition

        The biopharmaceutical industry is characterized by rapidly advancing technologies, strong emphasis on proprietary products and significantcompetition. While we believe that our products, technology, experience and scientific resources provide us with competitive advantages, we face potential competition from many sources, includingmajor pharmaceutical, specialty pharmaceutical and biotechnology companies, academic institutions and government agencies and public and private research institutions. Any product candidates that wesuccessfully develop and commercialize will compete with existing therapies and new therapies that may become available in the future.

        Weare initially developing mAbs as an adjunct therapy to be used with SOC antibiotics, which is a unique approach to treating lung infections that does not directly compete withantibiotics. Unlike antibiotics, mAbs enhance the body's ability to kill pathogens via an immunological mechanism. Additionally, in contrast to antibiotics, the dosing frequency of mAbs is once ortwice a month and may require only a single administration. Several companies are developing mAbs to treat infections, including Merck & Co., Medimmune, LLC (AstraZeneca),Arsanis, Inc., and Alopexx Enterprises, LLC. Arsanis recently announced that their Phase 2 clinical trial was stopped following interim analysis showing futility. The Arsanistrial was different in indication, study design, and patient population. We do not believe that the outcome of this trial has a material impact on the technical risk of our planned AR-301Phase 3 clinical trial.

Intellectual Property

        Our success depends, in part, on our ability to obtain, maintain, and enforce patents and other proprietary protections of our commerciallyimportant technologies and product candidates, to operate without infringing the proprietary rights of others, and to maintain trade secrets or other proprietary know-how, both in the U.S. and othercountries. Our ability to stop third parties from making, using, selling, offering to sell or importing our products will depend on the extent to which we have rights under valid and enforceablepatents or trade secrets that protect these activities. We seek to protect proprietary technology, inventions, and improvements that are commercially important to our business by seeking, maintaining,and defending patent rights, whether developed internally or licensed from third parties.

        Asof January 26, 2018, our patent estate includes approximately 42 issued patents (approximately 17 of which are in the U.S.) and approximately 24 pending patent applications(approximately four of which are in the U.S.), which we either own or for which we have an exclusive commercial license (either in its entirety or within our field of use), as is more fully describedbelow. Our patent families related to our product candidates are described below.

AR-301: Anti-Staphylococcus aureus HLA alphatoxin mAb

        OurAR-301 patent estate includes a patent family that we own related to AR-301 titled "Human Monoclonal Antibody against S.aureus derived alphatoxin and its use in treating or preventing abscess formation," which has a priority date of August 10, 2009. Issued claims include: composition ofmatter claims to a human mAb that binds to S. aureus alphatoxin and a cell line producing the antibody. Patents in this family have been issued inEurope, the U.S., China, Israel, Japan and Russia. National patent applications are currently pending in Canada, Korea, India and

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Brazil.Issued patents are expected to expire in 2030, absent any patent term adjustments or extensions. The portfolio is complemented by a patent family in-licensed from University of Chicago andtitled "Methods and Compositions related to Immunizing Against Staphylococcal Lung Diseases and Conditions." This patent family includes ten patents, which are granted in jurisdictions includingAustralia, China, Europe, Japan, Korea, and the U.S., and six patent applications that are pending in Brazil, Canada, China, Hong Kong, Japan and the U.S. Patents in this family are expected to expirein 2028, absent any patent term adjustments or extensions.

AR-105: Anti-Pseudomonas aeruginosa alginate mAb

        OurAR-105 patent estate includes two patent families that have been exclusively in-licensed from the Brigham Women's Hospital (Harvard University). The first family istitled "P.aeruginosa Mucoid Exopolysaccharide Specific Binding Peptides" and it is comprised of three issued U.S. patents that are expected to expire in 2022, absent any patent term adjustments orextensions. The second family is titled "Methods and compositions relating to mannuronic acid specific binding peptides," and it comprises one European patent that is expected to expire in 2025,absent any patent term adjustments or extensions. Claims in these patents include composition of matter, uses and methods of inducing immune response to the alginate epitope.We own a pending provisional application that, if issued, is expected to expire in 2037, absent any patent term adjustments or extensions.

AR-101: Anti-Pseudomonas aeruginosa LPS serotype O11mAb

        OurAR-101 patent estate includes a patent family, titled "Human Monoclonal Antibody Specific for LPS of serotype IATS 011 Pseudomonas aeruginosa," with issuedpatents in seven jurisdictions including Canada, Europe, China, India, Israel, Japan, and the U.S. The issued patents include claims directed to certain antibodies, variants or Fab fragments thereof,hybridomas producing the antibodies, as well as nucleic acids encoding the antibodies. In the U.S. issued claims are directed to antibodies with specific variable region sequences that bind LPSof the P. aeruginosa LPS serotype IATS 011, or with variable region sequences having 85% identity thereto. Similar claims were granted in Europe,Canada, China, Israel, India and Japan. Patents in this family are expected to expire in 2026, absent any patent term adjustments or extensions. Additionally, we also own a U.S. patent covering the O6serotype of P. aeruginosa LPS titled "Human Monoclonal Antibody Specific for LPS of Serotype IATS O6 Pseudomonas aeruginosa." This issuedUS patent is expected to expire in 2026, absent any patent term adjustments or extensions.

AR-501: Gallium citrate

        OurAR-501 patent estate includes three patent families, two of which we own and one of which is in-licensed from the University of Iowa Research Foundation. Thesepatents are directed to Gallium containing formulations for anti-infective indications and methods of using the same. These patent families include granted patents in Australia, Canada, China, Europe,Hong Kong, Japan, Mexico, New Zealand and the U.S. The in-licensed issued patents are expected to expire in 2024 and the patents that we own are expected to expire in 2030, absent any patent termadjustments or extensions.

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AR-201: Anti-Respiratory Syncytical Virus mAb

        Ourpatent estate for AR-201 comprises a U.S. patent and pending patent applications in Canada, China, Europe, India and the U.S. (divisional) titled "Human MonoclonalAntibody Specific for the F Protein of Respiratory Syncytial Virus (RSV)." Claims in the U.S. patent are directed to methods of producing certain antibodies with specificity to a region of RSV Fprotein and methods of treating or preventing RSV infections with such antibodies. The U.S. patent is expected to expire in 2034 and — in case of grant-currently pending patentapplications are expected to expire in 2035, absent any patent term adjustments or extensions.

AR-401: Anti-Acinetobacter baumannii mAb

        Ourpatent estate for AR-401 includes a patent family titled "Novel targets of Acinetobacter baumannii" with priority to2011. This family includes issued patents in Australia, China, Europe and the U.S. Patent applications are pending in Canada, China (divisional), Japan (divisional) and the U.S. (divisional). Claimsin these patents and applications include those directed to certain vaccine compositions and to mAb against outer membrane protein targets. Patents in this family are expected to expire in 2032, andany patents that may issue from the pending patent applications are expected to expire in 2032, absent any patent term adjustments or extensions.

        Complementingthe product specific patents is a pharmaceutical processing and formulation technology related portfolio comprising five patent families of which one was in-licensed. Thepatent families consist of eight national patents and patent applications on formulation and delivery technologies. The issued patents have expected expiration ranges between 2022 and 2030, and thepending patent applications are expected to expire between 2022 and 2037, absent any patent term adjustments or extensions. Claims in the patents are directed to formulation,stabilization, and delivery of pharmaceuticals. One of the patent applications was filed in June 2017 as an international application under the Patent Cooperation Treaty (PCT). This internationalpatent application is titled "Method for preparation of quick-dissolving thin films containing bioactive material with enhanced thermal stability," We plan to file national phase applications in 2018.

        Weare also actively pursuing additional patent applications in the U.S. and foreign patent jurisdictions for other preclinical product candidates and methods of use, includingadditional product candidates for infectious disease. In addition, we will pursue patent protection whenever it is deemed sufficiently beneficial for any product or product candidate and relatedtechnology we develop and/or acquire in the future.

        Thepatent positions of biotechnology companies like ours are generally uncertain and involve complex legal, scientific and factual questions. In addition, the coverage claimed in apatent application can be significantly reduced before the patent is issued. Consequently, we do not know whether the product candidates we are developing will gain patent protection or, if patentsare issued, whether they will provide significant proprietary protection or will be challenged, circumvented, invalidated, or found to be unenforceable. Because patent applications in the U.S. andcertain other jurisdictions are maintained in secrecy for 18 months, and since publication of discoveries in the scientific or patent literature often lags behind actual discoveries, we cannotbe certain of the priority of inventions or filing dates covered by pending patent applications. Moreover, we may have to participate in post-grant proceedings, interference proceedings, or

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third-partyex parte or inter partes reexamination proceedings before the U.S. Patent and TrademarkOffice, or in opposition proceedings in a foreign patent office, any of which could result in substantial cost to us, even if the eventual outcome is favorable to us. There can be no assurance thatthe patents, if issued, would be held valid and enforceable by a court of competent jurisdiction. An adverse outcome could subject us to significant liabilities to third parties, require disputedrights to be licensed from third parties or require us to cease using specific compounds or technology. To the extent it is prudent, we intend to bring litigation against third parties that we believeare infringing one or more of our patents or other intellectual property rights.

        Theterm of individual patents depends upon the legal term of the patents in the countries in which they are obtained. In most countries in which we file, the patent term is20 years from the earliest date of filing a non-provisional patent application. In the U.S., a patent term may belengthened by patent term adjustment, which compensates a patentee for administrative delays by the U.S. Patent and Trademark Office in granting a patent, or may be shortened if a patent is terminallydisclaimed over another patent. Some of our patents currently benefit from patent term adjustment and some of our patents that will be issued in the future may benefit from patent term adjustment.

        Thepatent term of a patent that covers an FDA-approved product may also be eligible for patent term extension, which permits patent term restoration as compensation for the patent termlost during the FDA regulatory review process. The Drug Price Competition and Patent Term Restoration Act of 1984, or the Hatch-Waxman Act, permits a patent term extension of up to five years beyondthe expiration of the patent. The length of the patent term extension is related to the length of time the product is under regulatory review. Patent term extension cannot extend the remaining term ofa patent beyond a total of 14 years from the date of product approval and only one patent applicable to an approved product may be extended. Similar provisions are available in Europe and othernon-U.S. jurisdictions to extend the term of a patent that covers an approved product. In the future, if and when our product candidates receive FDA approval, we expect to apply for patent-termextensions on patents covering those products.

        Toprotect our rights to any of our issued patents and proprietary information, we may need to litigate against infringing third parties, or avail ourselves of the courts or participatein hearings to determine the scope and validity of those patents or other proprietary rights. These types of proceedings are often costly and could be very time-consuming to us, and there can be noassurance that the deciding authorities will rule in our favor. An unfavorable decision could allow third-parties to use our technology without being required to pay us licensing fees or may compel usto license needed technologies to avoid infringing third-party patent and proprietary rights. Such a decision could even result in the invalidation or a limitation in the scope of our patents orforfeiture of the rights associated with our patents or pending patent applications.

        Wealso rely on trade secret protection for our confidential and proprietary information. No assurance can be given that others will not independently develop substantially equivalentproprietary information and techniques or otherwise gain access to our trade secrets or disclose such technology, or that we can meaningfully protect our trade secrets. However, we believe that thesubstantial costs and resources required to develop technological innovations will help us to protect the competitive advantage of our products.

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        Itis our policy to require our employees, consultants, outside scientific collaborators, sponsored researchers and other advisors to execute confidentiality agreements upon thecommencement of employment or consulting or collaborative relationships with us. These agreements provide that all confidential information developed or made known to the individual during the courseof the individual's relationship with us is to be kept confidential and not disclosed to third parties except in specific circumstances. In the case of employees, the agreements provide that allinventions conceived by the individual shall be and are our exclusive property. There can be no assurance, however, that these agreements will provide meaningful protection or adequate remedies forour trade secrets in the event of unauthorized use or disclosure of such information.

Licensing Agreements

University Licensing Agreements

The University of Chicago — Co-Exclusive Licensing Agreement

        We are party to a co-exclusive licensing agreement, or the UChicago agreement, with The University of Chicago, or UChicago for our AR-301product candidate, which we entered into in 2017. The UChicago agreement granted to us a worldwide co-exclusive, royalty-bearing license under UChicago's rights in methods relating to certain licensedpatents arising from the disclosure entitled, "Vaccine protection against Staphylococcus aureus pneumonia" regarding the work of Professors JulianeBubeck Wardenburg and Loaf Schneewind. The UChicago agreement also granted to us the right to sublicense. The Company paid UChicago $50,000 upon execution of the UChicago agreement.

        Wealso are obligated to pay UChicago low single digit percentage royalties on net sales of licensed products, with a minimum royalty required per year once sales begin, and ending whenthe last-to-expire patent covering such product expires, in addition to certain other milestone and other payments. The aggregate milestone payments under the UChicago agreement are up to $1,550,000.

        Theagreement provides that we have certain obligations to conduct further research and development, and are obligated to utilize reasonable efforts to commercialize the UChicagolicensed patent rights as licensed products.

        Theterm of the agreement continues until the expiration of the last to expire patents (which is expected to be in 2031), or until the agreement is earlier terminated. We may terminatethe agreement upon 90 days' prior written notice. Additionally, the UChicago Agreement will terminate upon any of the following events:

•

We fail to make a payment within 30 days written notice of default;



•

A breach of the agreement occurs that has not been cured in 30 days;



•

We become insolvent, make an assignment for the benefit of creditors, or if a petition for bankruptcy is filed;



•

We are dissolved or liquidated; and



•

If we fail to commence a Phase 3 clinical trial relating to AR-301 prior to June 13, 2022.

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The Brigham and Women's Hospital, Inc. — Exclusive Patent License Agreement

        We are party to an exclusive licensing agreement, or the BWH Agreement, with The Brigham and Women's Hospital, Inc., or BWH, a non-profitcorporation for our AR-105 product candidate, which we entered into in 2010. This agreement granted to us an exclusive, royalty-bearing license under its and Beth Israel Deaconess Medical Center's, orBIDMC, rights in methods and composition relating to specific binding peptides to P. aeruginosa mucoid exopolysaccharide to make, use and sell productsand processes for the treatment of pseudomonas infections in humans that are covered by such patent rights worldwide. The BWH Agreement also granted to us the right to sublicense. BWH and BIDMCretained the non-transferrable right to use such patent rights for academic and research purposes, and also to certain pre-existing rights of the U.S. government. The Company paid BWH $141,600 withinone year of execution of the BWH Agreement.

        Weare obligated to pay BWH low single digit percentage royalties on net sales from our and our sublicensee's sale of any commercialized licensed product or process, with a minimumroyalty required per year once sales begin, and certain other milestone and other payments. We are responsible for diligently prosecuting and maintaining the licensed patent rights, at our sole costand expense. The aggregate milestone payments under the BWH Agreement are up to $860,000.

        Theagreement provides that we have certain obligations to conduct further research and development, and are obligated to utilize reasonable efforts to commercialize, either directly orthrough a sublicensee, the licensed BWH patent rights as licensed products or processes.

        Theterm of the agreement continues until all patents and filed patent applications, included within the licensed BWH patents, have expired (which is expected to be in 2025) or beenabandoned, or until the agreement is earlier terminated. We may terminate the agreement on prior written notice to BWH. The Company has the right to terminate the agreement upon 90 days writtennotice. Additionally, the BWH Agreement will terminate upon any of the following events:

•

We fail to make a payment within 30 days written notice of default;



•

We fail to maintain the insurance requirements as defined in the BWH Agreement;



•

We become insolvent, make an assignment for the benefit of creditors, or if we file a petition for bankruptcy;



•

A breach of the agreement occurs that has not been cured in 60 days; and



•

Substantially all of our assets are seized or attached in a final, unappealed or unappealable order in conjunction with any action broughtagainst it by a third-party creditor, such that we are unable to perform our continuing obligations thereunder.

The University of Iowa Research Foundation — Exclusive Patent License Agreement

        We are party to an exclusive licensing agreement, or the UIRF agreement, with The University of Iowa Research Foundation, or UIRF, relating toour AR-501 product candidate, which we entered into in 2010. The agreement granted to us is an exclusive, royalty-bearing license under its rights in methods relating to gallium containing compoundsfor the treatment of infections to make, use and sell products that are covered by such patent rights worldwide. The

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UIRFagreement also granted to us the right to sublicense. UIRF retained the right and ability to grant right to use such patent rights for academic and research purposes, and also to certainpre-existing rights of the U.S. government including the rights of United States Department of Veterans Affairs. The Company paid $25,000 to UIRF in connection with entering into the UIRF agreement.

        Wealso are obligated to pay UIRF low single digit percentage royalties on net sales from our and our sublicensee's sale of any commercialized licensed product or process, and certainother milestone and other payments. The aggregate milestone payments under the UIRF agreement are up to $712,500. We are responsible for diligently prosecuting and maintaining the licensed UIRF patentrights, at our sole cost and expense.

        TheUIRF agreement provides that we have certain obligations to conduct further research and development, and are obligated to utilize reasonable efforts to commercialize, eitherdirectly or through a sublicensee, the licensed UIRF patent rights as licensed products or processes.

        Theterm of the agreement continues until the expiration of the last to expire patents (which is expected to be in 2034), or until the agreement is earlier terminated. We may terminatethe agreement on 90 days prior written notice to UIRF. Each party has the right to terminate the agreement for the other party's uncured material breach of obligations under the agreement.

        Additionally,the UIRF Agreement will terminate upon any of the following events:

•

We fail to make a payment upon 45 days written notice of default; or



•

We are involved in liquidation or bankruptcy proceedings unless the remaining party agrees not to terminate.

Brigham Young University — Exclusive Patent License Agreement

        We are party to an exclusive licensing agreement, or the BYU Agreement, with Brigham Young University, or BYU. This agreement granted to us anexclusive, royalty-bearing license under BYU's rights in stabilization of biological agents methods relating to human vaccines to make, use and sell products that are covered by such patent rightsworldwide. The agreement also granted to us the right to sublicense. BYU and the Church of Jesus Christ of Latter-day Saints and the Church Education System retained the right and ability to use suchpatent rights for academic and ecclesiastical purposes and also to purchase products using such patents rights at a discounted price.

        Wealso are obligated to pay BYU low single digit percentage royalties on the Adjusted Gross Sales as defined in the BYU Agreement, and certain other payments. The aggregate milestonepayments under the BYU Agreement are up to $400,000. BYU is responsible for diligently prosecuting and maintaining the licensed BYU patent rights and we will reimburse them for one-third of theircosts.

        Theagreement provides that we have certain obligations to conduct further research and development, and are obligated to utilize reasonable efforts to commercialize, either directly orthrough a sublicensee, the licensed BYU patent rights as licensed products or processes.

        Theterm of the BYU Agreement continues until the expiration of the last to expire patents (which is expected to be in 2022), or until the agreement is earlier terminated. We mayterminate

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theagreement on prior written notice to BYU. Each party has the right to terminate the agreement for the other party's uncured material breach of obligations under the agreement. Additionally, theBYU Agreement will terminate upon any of the following events:

•

We are placed in the hands of a receiver or make a general assignment for the benefit of creditors, such that we are unable to perform ourobligations under the agreement; or



•

Substantially all of our assets or our successor-in interest are seized or attached in a final, unappealed or unappealable order in conjunctionwith any action brought against us by a third party creditor, such that we are unable to perform our continuing obligations hereunder.

Public Health Service Licensing Agreements

NIH — Exclusive and Non-Exclusive Patent License Agreement

        We are party to an exclusive and non-exclusive licensing agreement, or the NIH Agreement, with the NIH on July 11^th, 2005relating to roatvirus vaccine development. This agreement granted to us an exclusive, royalty-bearing license in Europe, Canada, and the U.S. and non-exclusive rights worldwide under its rights in ahuman rotavirus vaccine based on their human-bovine rotavirus reassortants to make, use and sell products and processes that are covered by such patent rights. The NIH Agreement also granted to us theright to sublicense.

        Ourlicense under this agreement is subject to the U.S. government's retained rights under a non-exclusive, worldwide, royalty-free license for the practice of all inventions licensedunder the Public Health Service, or PHS, patent rights, by or on behalf of the U.S. government and on behalf of any foreign government or international organization pursuant to any existing or futuretreaty or agreement to which the U.S. government is a signatory. For purposes of encouraging basic research, the U.S. government also reserves the right to grant or require us to grant to a thirdparty on reasonable terms a non-exclusive, non-transferable license to make and use the licensed products or licensed processes for research purpose only, but subject to PHS consulting with us in theevent such third party is a commercial entity. Under certain exceptional and enumerated circumstances, the U.S. government may require us to grant a sublicense to a responsible third party applicant,on terms that are reasonable under the circumstances. The PHS takes responsibility for all aspects of the preparation, filing, prosecution and maintenance of any and all patent applications or patentsincluded in the licensed PHS patent rights, subject to our payment of certain patent-related expenses.

        Wealso are obligated to pay PHS low single digit percentage royalties on net sales from our and our sublicensee's sale of any commercialized licensed product or process with a minimumroyalty required per year, and certain other payments. The aggregate milestone payments under the BYU Agreement are up to $850,000. PHS is responsible for diligently prosecuting and maintaining thelicensed PHS patent rights, and we reimburse them for a portion of their costs.

        Theagreement provides that we have certain obligations to conduct further research and development, and are obligated to utilize reasonable efforts to commercialize, either directly orthrough a sublicensee, the licensed PHS patent rights as licensed products or processes.

        Theterm of the NIH Agreement continues until expiration of all royalty obligations, included within the licensed PHS patents, or until the agreement is earlier terminated. We mayterminate

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theagreement upon 60 days prior written notice to PHS. Each party has the right to terminate the agreement for the other party's uncured material breach of obligations under the agreement. Inaddition, the NIH Agreement will terminate upon any of the following events:

•

We become insolvent or involved in a bankruptcy petition;



•

We do not meet certain obligations of the NIH Agreement;



•

Public health and safety require the termination of the NIH Agreement; or



•

We do not satisfy certain federal regulation public use requirements.

Cystic Fibrosis Foundation Agreement

        In December 2016, we received an award for up to $2.9 million from the Cystic Fibrosis Foundation to advance research on potential drugsutilizing inhaled gallium citrate anti-infective. Under the award agreement, the Cystic Fibrosis Foundation will make payments to us as certain milestones are met. The award agreement also contains aprovision whereby if we spend less on developing a potential drug utilizing inhaled gallium citrate anti-infective than we actually receive under this award agreement, we will be required to returnthe excess portion of the award to the Cystic Fibrosis Foundation.

        Inthe event that development efforts are successful and we commercialized a drug from these related development efforts, we may be subject to pay to Cystic Fibrosis Foundation aone-time amount equal to the awarded amount. Such amount shall be paid in as few as three and not more than five annual installments.

        Inaddition to the amount payable above, we will pay to Cystic Fibrosis Foundation a one-time amount equal to the amount of funding from Cystic Fibrosis Foundation under the agreement,within 60 days after the end of the first calendar year during which aggregate net sales of compounds containing gallium citrate or gallium nitrate in citrate buffer as an active ingredientexceed $100 million.

        Inthe event that we license rights to the product in the field to a third-party, sell the product, or consummate a change of control transaction prior to the first commercial sale, weshall pay to the Cystic Fibrosis Foundation an amount equal to two times the actual awarded amount under the agreement, if the change of control transaction occurs prior to the completion of the firstPhase 2b (or equivalent) clinical study with respect to the product; and four times the actual awarded amount if the change of control transaction occurs after the completion of thePhase 2b clinical trial specified above. The payment shall be made within sixty days after the closing of such a transaction.

Program for Appropriate Technology in Health and PATH Vaccine Solutions

        We granted the Program for Appropriate Technology in Health, or PATH, a global non-profit organization, and the PATH Vaccine Solutions anon-exclusive license, with right to sublicense formulations, for use with the measles, rotavirus, live-attenuated influenza, pneumococcal and enteric vaccines only for sale in developing countries.

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        Wehave also agreed to provide rotavirus vaccines to public sector purchasers in developing countries at a preferential price relative to private sector purchasers in developingcountries where the rotavirus vaccine utilizing the enabling formulation technology is offered for sale.

Corporate Licensing Arrangements

Kenta Biotech Ltd.

        We are a party to an asset purchase agreement with Kenta Biotech Ltd., or Kenta, a for profit corporation duly incorporated in Schlieren(Canton of Zurich, Switzerland). The asset purchase agreement contains a licensing arrangement based upon the worldwide out-licensing or net sales of certain of Kenta's physical assets, contracts andtechnology. Pursuant to such agreement, we were obligated to pay Kenta a fixed purchase price, which was fully paid during 2013 and 2014, and are obligated to pay a declining scale of royalties ongross licensing revenues from either out-licensing of the assets or net sales revenues actually received by us up to a maximum of $50,000,000.

        Theagreement also assigned and transferred certain of Kenta's physical assets, contracts and technology to us. The physical assets included all physical assets owned or controlled byKenta, including but not limited to cell lines, genes, antibodies, diagnostic assays and related documentation, which were related to Kenta's MabIgX technology platform for hybridoma generation andits mAb targeting S. aureus, P. aeruginosa, A. baumanniiand RSV. The technology included all intellectual property, including but not limited to patents, patent applications, trademarks, knowhow, trade secrets, regulatory filings, clinical trials, clinicaltrial information, all supporting documentation and all other related intellectual property which are related to Kenta'sMabIgX technology platform for hybridoma generation and its mAb targeting S. aureus, P. aeruginosa, A.baumannii and RSV. The contracts included the contracts and agreements(including all rights and obligations thereunder), whether oral or written, which Kenta has concluded and which pertain to the assets. The contracts were primarily related to the ongoing clinicaltrial of AR-301.

Emergent Product Development Gaithersburg Inc.

        We are party to a license agreement, or the Emergent Agreement, with Emergent Product Development Gaithersburg Inc., or Emergent, whichwe entered into in 2010. We granted Emergent an exclusive, perpetual, royalty-bearing license to use certain of our patents and related know how for the prevention or treatment of infection or illnesscaused by biodefense pathogens. We also granted a non-exclusive, royalty-bearing license to use certain of our patents and related know how for the prevention or treatment of tularemia and viralhemorrhagic fever indications. Both exclusive and non-exclusive licenses grants Emergent the opportunity to Exploit Licensed Products as defined in the Emergent Agreement in all of the countries ofthe world. There are currently no commercialized Exploit Licensed Products using this technology.

        Emergentis obligated to pay us low single digit percentage royalties on net sales from their and their sublicensee's sale of any commercialized licensed product, and certain otherpayments. The aggregate milestone payments that we are entitled to pursuant to the Emergent Agreement are up to $2,750,000.

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        Theterm of the Emergent Agreement continues until expiration of all royalty obligations or until the agreement is earlier terminated. Emergent may terminate the agreement upon60 days prior written notice. In addition, the Emergent Agreement terminates in the event the parties mutually agree to terminate the agreement.

Joint Venture

Joint Venture with Shenzhen Hepalink Pharmaceutical Group Co., Ltd.

        On February 11, 2018, we entered into a Joint Venture Contract, or the JV Agreement, with Shenzhen Hepalink PharmaceuticalGroup Co., Ltd., a People's Republic of China company, or Hepalink, pursuant to which we formed a joint venture company named Shenzen Arimab BioPharmaceuticals Co., Ltd.,or SABC, a People's Republic of China Company, to develop, manufacture, import and distribute AR-101 and AR-301 in China, Hong Kong, Macau and Taiwan, collectively, referred to as theTerritory. SABC was formed on July 2, 2018 after receiving the required regulatory approval in China.

        Hepalinkcontributed the equivalent of $6.0 million in renmimbi, the official currency of the People's Republic of China, and owns 51% of the capital of SABC and wecontributed (i) $1.0 million in cash and (ii) a license to AR-101 and AR-301 pursuant to a Technology License and Collaboration Agreement between us and SABC, and weown 49% of the capital of SABC. In addition, Hepalink will provide SABC with clinical and regulatory personnel services for clinical and regulatory review, application and filing procedures inthe Territory and we will provide clinical and regulatory personnel services to assist in coordination of the execution of the clinical study in China and also with CMC personnel services for drugsupply and manufacturing planning. Upon the completion of certain milestone events, including obtaining approval for a phase III clinical trial in mainland China, Hepalink will be obligated tocontribute an equivalent of $9.0 million in renmimbi in exchange for additional equity in SABC. Following such additional contribution, our ownership interest in SABC will be proportionatelyreduced.

        Pursurantto the Technology License and Collaboration Agreement, we granted an exclusive license to AR-101 and AR-301 in the Territory. At any time during the Term, SABC may, at itsconvenience, terminate the agreement in its entirety with ninety days' prior written notice to us, and we may terminate the agreement in its entirety with ninety days' prior written notice to SABC inthe event that SABC has not complied with its obligation to use commercially reasonably efforts to develop or commercialize a product in accordance with the terms of the agreement and the breach hasnot been remedied at the end of a sixty day period as set forth in the breach notice.We may also immediately terminate this agreement in its entirety in the event that Hepalink does not make the additional equity investment in the Company of no less than $9.0 million inaccordance with the Joint Venture Contract, or if SABC materially breached its confidentiality obligations under the agreement, or in the event of a change of control of SABC.

        TheBoard of Directors of SABC shall consist of five directors, of which Hepalink shall appoint three members and we shall appoint 2 members. The term of office foreach director shall be for four years. The Chief Executive Officer and Chief Financial Officer of SABC will be approved by unanimous consent of the Board of Directors of SABC. The term of SABCshall be 20 years from the date of formation.

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        TheJV Agreement will terminate and SABC will be dissolved in the event that:

•

The term expires and is not extended;



•

The parties decide to terminate the JV Agreement;



•

A party fails to contribute funds for the capital it subscribed for and such failure exceeds six months;



•

A party is involved in liquidation or bankruptcy proceedings unless the remaining party agrees not to terminate;



•

A party fails to obtain approval of a resolution requiring the unanimous vote of the Board and such party notifies the other party that suchfailure will materially adversely affect SABC and cannot be resolved;



•

A force majeure event prevails for a period in excess of six months;



•

A breach of the agreement occurs and has not been cured in 60 days; or



•

Either we or SABC terminates the Technology License and Collaboration Agreement in accordance with its terms.

Collaboration Agreements

Collaboration Agreement with GlaxoSmithKline

        We have a collaborative and option agreement with GlaxoSmithKline Biologicals S.A., or GSK, aimed at evaluating improved formulations fora rotavirus vaccine. GSK has until at least January 2019 to exercise its option, at which point we would negotiate certain licenses wherein GSK would license certain of our patents and related knowhow relating to rotavirus in order to research, develop, market and commercialize a rotavirus vaccine. While the collaboration is active, our main focus and the significant portion of our capitaldeployment is on our other projects. As such, the aforementioned collaboration is not viewed to be critical to our business plan. If phase 1 of this collaboration is initiated, GSK would fund80% of the collabarotion funding. We also would be due a license initiation fee of up to $600,000 and $100,000 upon successful completion of a phase I clinical trial.

Government Regulation

        We operate in a highly regulated industry that is subject to significant federal, state, local and foreign regulation. Our present and futurebusiness has been, and will continue to be, subject to a variety of laws including, the Federal Food, Drug, and Cosmetic Act, or FDC Act, and the Public Health Service Act, among others.

        TheFDC Act and other federal and state statutes and regulations govern the testing, manufacture, safety, effectiveness, labeling, storage, record keeping, approval, advertising andpromotion of our products. As a result of these laws and regulations, product development and product approval processes are very expensive and time-consuming.

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FDA Approval Process

        In the United States, pharmaceutical products, including biologics, are subject to extensive regulation by the FDA. The FDC Act and otherfederal and state statutes and regulations, govern, among other things, the research, development, testing, manufacture, storage, recordkeeping, approval, labeling, promotion and marketing,distribution, post-approval monitoring and reporting, sampling, and import and export of pharmaceutical products. Failure to comply with applicable U.S. requirements may subject a company to a varietyof administrative or judicial sanctions, such as FDA refusal to approve pending new drug applications, or NDAs, or biologic license applications, or BLAs, warning letters, product recalls, productseizures, total or partial suspension of production or distribution, injunctions, fines, civil penalties, and criminal prosecution.

        Pharmaceuticalproduct development in the United States typically involves preclinical laboratory and animal tests, the submission to the FDA of an IND, which must become effectivebefore clinical testing may commence, and adequate and well-controlled clinical trials to establish the safety and effectiveness of the drug or biologic for each indication for which FDA approval issought. Satisfaction of FDA pre-market approval requirements typically takes many years and the actual time required may vary substantially based upon the type, complexity and novelty of the productor disease.

        Preclinicaltests include laboratory evaluation as well as animal trials to assess the characteristics and potential pharmacology and toxicity of the product. The conduct of thepreclinical tests must comply with federal regulations and requirements including good laboratory practices. The results of preclinical testing are submitted to the FDA as part of an IND along withother information, including information about product chemistry, manufacturing and controls, and a proposed clinical trial protocol. Long term preclinical tests, such as animal tests of reproductivetoxicity and carcinogenicity, may continue after the IND is submitted.

        A30-day waiting period after the submission of each IND is required prior to the commencement of clinical testing in humans. If the FDA has not objected to the IND within this 30-dayperiod, the clinical trial proposed in the IND may begin.

        Clinicaltrials involve the administration of the investigational drug to healthy volunteers or patients under the supervision of a qualified investigator. Clinical trials must beconducted in compliance with federal regulations and good clinical practices, or GCP, as well as under protocolsdetailing the objectives of the trial, the parameters to be used in monitoring safety and the effectiveness criteria to be evaluated. Each protocol involving testing on U.S. patients and subsequentprotocol amendments must be submitted to the FDA as part of the IND.

        TheFDA may order the temporary or permanent discontinuation of a clinical trial at any time or impose other sanctions if it believes that the clinical trial is not being conducted inaccordance with FDA requirements or presents an unacceptable risk to the clinical trial patients. The clinical trial protocol and informed consent information for patients in clinical trials must alsobe submitted to an institutional review board, or IRB, for approval. An IRB may also require the clinical trial at the site to be halted, either temporarily or permanently, for failure to comply withthe IRB's requirements, or may impose other conditions.

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        Clinicaltrials to support NDAs or BLAs, which are applications for marketing approval, are typically conducted in three sequential Phases, but the Phases may overlap. In Phase 1,the initial introduction of the investigational drug candidate into healthy human subjects or patients, the investigational drug is tested to assess metabolism, pharmacokinetics, pharmacologicalactions, side effects associated with increasing doses and, if possible, early evidence on effectiveness. Phase 2 usually involves trials in a limited patient population, to determine theeffectiveness of the investigational drug for a particular indication or indications, dosage tolerance and optimum dosage, and identify common adverse effects and safety risks. In the case of productcandidates for severe or life-threatening diseases such as pneumonia, the initial human testing is often conducted in patients rather than in healthy volunteers.

        Ifan investigational drug demonstrates evidence of effectiveness and an acceptable safety profile in Phase 2 evaluations, Phase 3 clinical trials are undertaken to obtainadditional information about clinical efficacy and safety in a larger number of patients, typically at geographically dispersed clinical trial sites, to permit the FDA to evaluate the overallbenefit-risk relationship of the investigational drug and to provide adequate information for its labeling.

        Aftercompletion of the required clinical testing, an NDA or, in the case of a biologic, a BLA, is prepared and submitted to the FDA. FDA approval of the marketing application isrequired before marketing of the product may begin in the United States. The marketing application mustinclude the results of all preclinical, clinical and other testing and a compilation of data relating to the product's pharmacology, chemistry, manufacture, and controls.

        TheFDA has 60 days from its receipt of an NDA or BLA to determine whether the application will be accepted for filing based on the agency's threshold determination that it issufficiently complete to permit substantive review. Once the submission is accepted for filing, the FDA begins an in-depth review. The FDA has agreed to certain performance goals in the review ofmarketing applications. Most such applications for non-priority drug products are reviewed within ten months. The review process may be extended by the FDA for three additional months to consider newinformation submitted during the review or clarification regarding information already provided in the submission. The FDA may also refer applications for novel drug products or drug products thatpresent difficult questions of safety or efficacy to an advisory committee, typically a panel that includes clinicians and other experts, for review, evaluation and a recommendation as to whether theapplication should be approved. The FDA is not bound by the recommendation of an advisory committee, but it generally follows such recommendations. Before approving a marketing application, the FDAwill typically inspect one or more clinical sites to assure compliance with GCP.

        Additionally,the FDA will inspect the facility or the facilities at which the drug product is manufactured. The FDA will not approve the NDA or, in the case of a biologic, the BLAunless compliance with cGMPs is satisfactory and the marketing application contains data that provide substantial evidence that the product is safe and effective in the indication studied.Manufacturers of biologics also must comply with FDA's general biological product standards.

        Afterthe FDA evaluates the NDA or BLA and the manufacturing facilities, it issues an approval letter or a complete response letter. A complete response letter outlines the deficienciesin the submission and may require substantial additional testing or information in order for the FDA to reconsider the application. If and when those deficiencies have been addressed in a

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resubmissionof the marketing application, the FDA will re-initiate review. If the FDA is satisfied that the deficiencies have been addressed, the agency will issue an approval letter. The FDA hascommitted to reviewing such resubmissions in two or six months depending on the type of information included. It is not unusual for the FDA to issue a complete response letter because it believes thatthe drug product is not safe enough or effective enough or because it does not believe that the data submitted are reliable or conclusive.

        Anapproval letter authorizes commercial marketing of the drug product with specific prescribing information for specific indications. As a condition of approval of the marketingapplication, the FDA may require substantial post-approval testing and surveillance to monitor the drug product's safety or efficacy and may impose other conditions, including labeling restrictions,which can materially affect the product's potential market and profitability. Once granted, product approvals may be withdrawn if compliance with regulatory standards is not maintained or problems areidentified following initial marketing.

Orphan Drug Act in the United States

        The Orphan Drug Act provides incentives to manufacturers to develop and market drugs for rare diseases and conditions affecting fewer than200,000 persons in the U.S. at the time of application for orphan drug designation. Orphan drug designation must be requested before submitting a BLA. Orphan drug designation does not convey anyadvantage in, or shorten the duration of, the regulatory review and approval process. If a product that has orphan drug designation subsequently receives the first FDA approval for the disease forwhich it has such designation, the holder of the approval is entitled to a seven-year exclusive marketing period in the U.S. for that product except in very limited circumstances. For example, a drugthat the FDA considers to be clinically superior to, or different from, another approved orphan drug, even though for the same indication, may also obtain approval in the U.S. during the seven-yearexclusive marketing period. In addition, holders of exclusivity for orphan drugs are expected to assure the availability of sufficient quantities of their orphan drugs to meet the needs of patients.Failure to do so could result in the withdrawal of marketing exclusivity for the drug.

Orphan Designation and Exclusivity in the European Union

        Products authorized as "orphan medicinal products" in the EU are entitled to certain exclusivity benefits. In accordance with Article 3of Regulation (EC) No. 141/2000 of the European Parliament and of the Council of 16 December 1999 on orphan medicinal products, a medicinal product may be designated as an orphanmedicinal product if: (1) it is intended for the diagnosis, prevention or treatment of a life-threatening or chronically debilitating condition; (2) either (a) such conditionaffects no more than five in 10,000 persons in the European Union when the application is made, or (b) the product, without the incentives derived from orphanmedicinal product status, would not generate sufficient return in the European Union to justify investment; and (3) there exists no satisfactory method of diagnosis, prevention or treatment ofsuch condition authorized for marketing in the EU, or if such a method exists, the product will be of significant benefit to those affected by the condition.

        Anapplication for orphan drug designation must be submitted before the application for marketing authorization. Orphan drug designation does not convey any advantage in, or shorten theduration of, the regulatory review and approval process.

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        Productsauthorized in the EU as orphan medicinal products are entitled to 10 years of market exclusivity. The 10-year market exclusivity may be reduced to six years if, at theend of the fifth year, it is established that the product no longer meets the criteria for orphan designation, for example, if the product is sufficiently profitable not to justify maintenance ofmarket exclusivity. Additionally, marketing authorization may be granted to a similar product during the 10-year period of market exclusivity for the same therapeutic indication at any timeif:

•

The second applicant can establish in its application that its product, although similar to the orphan medicinal product already authorized, issafer, more effective or otherwise clinically superior;



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The holder of the marketing authorization for the original orphan medicinal product consents to a second orphan medicinal product application;or



•

The holder of the marketing authorization for the original orphan medicinal product cannot supply enough orphan medicinal product.

Other Regulatory Requirements

        Once a NDA or BLA is approved, a product will be subject to certain post-approval requirements. For instance, the FDA closely regulates thepost-approval marketing and promotion of therapeutic products, including standards and regulations for direct-to-consumer advertising, off-label promotion, industry-sponsored scientific andeducational activities and promotional activities involving the internet.

        Biologicsmay be marketed only for the approved indications and in accordance with the provisions of the approved labeling. Changes to some of the conditions established in an approvedapplication, including changes in indications, labeling, or manufacturing processes or facilities, require submission and FDA approval of a new BLA or BLA supplement, before the change can beimplemented. A BLA supplement for a new indication typically requires clinical data similar to that in the original application, and the FDA uses the same procedures and actions in reviewing BLAsupplements as it does in reviewing BLAs. We cannot be certain that the FDA or any other regulatory agency will grant approval for our product candidates for any other indications or any other productcandidate for any indication on a timely basis, if at all.

        Adverseevent reporting and submission of periodic reports is required following FDA approval of a BLA. The FDA also may require post-marketing testing, known as Phase 4 testing,risk evaluation and mitigation strategies, and surveillance to monitor the effects of an approved product or place conditions on an approval that could restrict the distribution or use of the product.In addition, quality control as well as product manufacturing, packaging, and labeling procedures must continue to conform to cGMPs after approval. Manufacturers and certain of their subcontractorsare required to register their establishments with the FDA and certain state agencies, and are subject to periodic unannounced inspections by the FDA during which the agency inspects manufacturingfacilities to assess compliance with cGMPs. Accordingly, manufacturers must continue to expend time, money and effort in the areas of production and quality control to maintain compliance with cGMPs.Regulatory authorities may withdraw product approvals or request product recalls if a company fails to comply with regulatory standards, if it encounters problems following initial marketing, or ifpreviously unrecognized problems are subsequently discovered.

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Companion Diagnostic Review and Approval

        Some of our product candidates currently rely upon the use of a companion microbial diagnostic test to select patients who are infected witheither S. aureus, P. aeruginosa, or A. baumannii bacteria and in the future we may utilize other biomarkers as companion diagnostic tests for ourother product candidates. Approval of our product candidates may require FDA approval of a Premarket Approval Application, or PMA, for a reproducible, validated diagnostic test to be used with our mAbproduct candidates.

        ThePMA process is costly, lengthy, and uncertain, although the PMA review for the microbial tests is not currently planned to occur concurrently with the development and review of a BLAfor our product candidates. The receipt and timing of PMA approval may have a significant effect on the receipt and timing of commercial approval for our product candidates. Human diagnostic productsare subject to pervasive and ongoing regulatory obligations, including the submission of medical device reports, adherence to the Quality Systems Regulation, recordkeeping and product labeling, asenforced by the FDA and comparable state authorities.

U.S. Foreign Corrupt Practices Act

        The U.S. Foreign Corrupt Practices Act, to which we are subject, prohibits corporations and individuals from engaging in certain activities toobtain or retain business or to influence a person working in an official capacity. It is illegal to pay, offer to pay or authorize the payment of anything of value to any foreign government official,government staff member, political party or political candidate in an attempt to obtain or retain business or to otherwise influence a person working in an official capacity.

Federal and State Fraud and Abuse Laws

        Healthcare providers, physicians and third-party payors play a primary role in the recommendation and prescription of drug and biologic productcandidates which obtain marketing approval. In addition to FDA restrictions on marketing of pharmaceutical products, pharmaceutical manufacturers are exposed, directly, or indirectly, throughcustomers, to broadly applicable fraud and abuse and other healthcare laws and regulations that may affect the business or financial arrangements and relationships through which a pharmaceuticalmanufacturer can market, sell and distribute drug and biologic products. These laws include, but are not limited to:

        Thefederal Anti-Kickback Statute which prohibits, any person or entity from, among other things, knowingly and willfully offering, paying, soliciting, or receiving any remuneration,directly or indirectly, overtly or covertly, in cash or in-kind, to induce or reward either the referring of an individual for, or the purchasing, leasing, ordering, or arranging for the purchase,lease, or order of any healthcare item or service reimbursable, in whole or in part, under Medicare, Medicaid, orany other federally financed healthcare program. The term "remuneration" has been broadly interpreted to include anything of value. This statute has been interpreted to apply to arrangements betweenpharmaceutical manufacturers on one hand and prescribers, purchasers, and formulary managers on the other hand. Although there are a number of statutory exceptions and regulatory safe harborsprotecting certain common activities from prosecution, the exceptions and safe harbors are drawn narrowly, and practices that involve remuneration intended to induce

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prescribing,purchases, or recommendations may be subject to scrutiny if they do not qualify for an exception or safe harbor.

        Thefederal false claims and civil monetary penalty laws, including the Federal False Claims Act, which imposes significant penalties and can be enforced by private citizens throughcivil qui tam actions, prohibits any person or entity from, among other things, knowingly presenting, or causing to be presented, a false, fictitious or fraudulent claim for payment to the federalgovernment, or knowingly making, using or causing to be made, a false statement or record material to a false or fraudulent claim to avoid, decrease or conceal an obligation to pay money to thefederal government. In addition, a claim including items or services resulting from a violation of the federal Anti-Kickback Statute constitutes a false or fraudulent claim for purposes of the FederalFalse Claims Act. As a result of a modification made by the Federal Fraud Enforcement and Recovery Act of 2009, a claim includes "any request or demand" for money or property presented to the U.S.government. In addition, manufacturers can be held liable under the False Claims Act even when they do not submit claims directly to government payors if they are deemed to "cause" the submission offalse or fraudulent claims. Criminal prosecution is also possible for making or presenting a false, fictitious or fraudulent claim to the federal government. Recently, several pharmaceutical and otherhealthcare companies have been prosecuted under these laws for allegedly providing free product to customers with certain expectation that the customers would bill federal programs for the product.Other companies have been prosecuted for causing false claims to be submitted because of the company's marketing of the product for unapproved, and thus non-reimbursable, uses.

        Thefederal Health Insurance Portability and Accountability Act of 1996, or HIPAA, which, among other things, imposes criminal liability for executing or attempting to execute a schemeto defraud any healthcare benefit program, including private third-party payors, knowingly and willfully embezzling or stealing from a healthcare benefit program, willfully obstructing a criminalinvestigation of a healthcare offense, and creates federal criminal laws that prohibit knowingly and willfully falsifying, concealing or covering up a material fact or making any materially false,fictitious or fraudulent statements or representations, or making or using any false writing ordocument knowing the same to contain any materially false, fictitious or fraudulent statement or entry in connection with the delivery of, or payment for, benefits, items or services.

        HIPAA,as amended by the Health Information Technology for Economic and Clinical Health Act of 2009, or HITECH, and its implementing regulations, which impose certain requirementsrelating to the privacy, security, transmission and breach reporting of individually identifiable health information upon entities subject to the law, such as health plans, healthcare clearinghousesand certain healthcare providers and their respective business associates that perform services for them that involve individually identifiable health information. HITECH also created new tiers ofcivil monetary penalties, amended HIPAA to make civil and criminal penalties directly applicable to business associates, and gave state attorneys general new authority to file civil actions fordamages or injunctions in U.S. federal courts to enforce the federal HIPAA laws and seek attorneys' fees and costs associated with pursuing federal civil actions.

        Thefederal physician payment transparency requirements, sometimes referred to as the "Physician Payments Sunshine Act," and its implementing regulations, which require certainmanufacturers of drugs, devices, biologics and medical supplies for which payment is available under Medicare, Medicaid or the Children's Health Insurance Program (with certain exceptions)

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toreport annually to the United States Department of Health and Human Services, or HHS, information related to payments or other transfers of value made to physicians (defined to include doctors,dentists, optometrists, podiatrists and chiropractors) and teaching hospitals, as well as ownership and investment interests held by physicians and their immediate family members.

        Stateand foreign law equivalents of each of the above federal laws, such as anti-kickback and false claims laws, that may impose similar or more prohibitive restrictions, and may applyto items or services reimbursed by non-governmental third-party payors, including private insurers.

        Statelaws that require pharmaceutical companies to implement compliance programs, comply with the pharmaceutical industry's voluntary compliance guidelines and the relevant complianceguidance promulgated by the federal government, or to track and report gifts, compensation and other remuneration provided to physicians and other healthcare providers, state and local laws thatrequire the registration of pharmaceutical sales representatives, and other federal, state andforeign laws that govern the privacy and security of health information or personally identifiable information in certain circumstances, including state health information privacy and data breachnotification laws which govern the collection, use, disclosure, and protection of health-related and other personal information, many of which differ from each other in significant ways and often arenot pre-empted by HIPAA, thus requiring additional compliance efforts.

        Becauseof the breadth of these laws and the narrowness of the safe harbors, it is possible that some business activities can be subject to challenge under one or more of such laws. Thescope and enforcement of each of these laws is uncertain and subject to rapid change in the current environment of healthcare reform, especially in light of the lack of applicable precedent andregulations. Federal and state enforcement bodies have recently increased their scrutiny of interactions between healthcare companies and healthcare providers, which has led to a number ofinvestigations, prosecutions, convictions and settlements in the healthcare industry.

        Ensuringthat business arrangements with third parties comply with applicable healthcare laws and regulations is costly and time consuming. If business operations are found to be inviolation of any of the laws described above or any other applicable governmental regulations a pharmaceutical manufacturer may be subject to penalties, including civil, criminal andadministrative penalties, damages, fines, disgorgement, individual imprisonment, exclusion from governmental funded healthcare programs, such as Medicare and Medicaid, contractual damages,reputational harm, diminished profits and future earnings, additional reporting obligations and oversight if subject to a corporate integrity agreement or other agreement to resolve allegations ofnon-compliance with these laws, and curtailment or restructuring of operations, any of which could adversely affect a pharmaceutical manufacturer's ability to operate its business and the results ofits operations.

Healthcare Reform in the United States

        In the United States, there have been, and continue to be, a number of legislative and regulatory changes and proposed changes to the healthcaresystem that could affect the future results of pharmaceutical manufactures' operations. In particular, there have been and continue to be a number of initiatives at the federal and state levels thatseek to reduce healthcare costs. Most recently, the Patient Protection and Affordable Care Act, or PPACA, was enacted in March 2010, which includes measures to significantly change the way healthcareis financed by both

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governmentaland private insurers. Among the provisions of the PPACA of greatest importance to the pharmaceutical and biotechnology industry are thefollowing:

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an annual, nondeductible fee on any entity that manufactures or imports certain branded prescription drugs and biologic agents, apportionedamong these entities according to their market share in certain government healthcare programs;



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implementation of the federal physician payment transparency requirements, sometimes referred to as the "Physician Payments Sunshine Act";



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a licensure framework for follow-on biologic products;



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a new Patient-Centered Outcomes Research Institute to oversee, identify priorities in, and conduct comparative clinical effectiveness research,along with funding for such research;



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establishment of a Center for Medicare Innovation at the Centers for Medicare & Medicaid Services to test innovative payment and servicedelivery models to lower Medicare and Medicaid spending, potentially including prescription drug spending;



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an increase in the statutory minimum rebates a manufacturer must pay under the Medicaid Drug Rebate Program, to 23.1% and 13% of the averagemanufacturer price for most branded and generic drugs, respectively and capped the total rebate amount for innovator drugs at 100% of the Average Manufacturer Price, or AMP;



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a new methodology by which rebates owed by manufacturers under the Medicaid Drug Rebate Program are calculated for certain drugs and biologics,including our product candidates, that are inhaled, infused, instilled, implanted or injected;



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extension of manufacturers' Medicaid rebate liability to covered drugs dispensed to individuals who are enrolled in Medicaid managed careorganizations;



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expansion of eligibility criteria for Medicaid programs by, among other things, allowing states to offer Medicaid coverage to additionalindividuals and by adding new mandatory eligibility categories for individuals with income at or below 133% of the federal poverty level, thereby potentially increasing manufacturers' Medicaid rebateliability;



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a new Medicare Part D coverage gap discount program, in which manufacturers must agree to offer 50% (and 70% commencing January 1, 2019)point-of-sale discounts off negotiated prices of applicable brand drugs to eligible beneficiaries during their coverage gap period, as a condition for the manufacturer's outpatient drugs to be coveredunder Medicare Part D; and



•

expansion of the entities eligible for discounts under the Public Health program.

        Someof the provisions of the PPACA have yet to be implemented, and there have been legal and political challenges to certain aspects of the PPACA. Since January 2017, President Trumphas signed two executive orders and other directives designed to delay, circumvent, or loosen certain requirements mandated by the PPACA. Concurrently, Congress has considered legislation that wouldrepeal or repeal and replace all or part of the PPACA. While Congress has not passed repeal legislation, two bills affecting the implementation of certain taxes under the PPACA have been signed intolaw. The Tax Cuts and Jobs Act of 2017 includes a provision repealing, effective January 1, 2019, the tax-based shared responsibility payment imposed by the PPACA on certain

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individualswho fail to maintain qualifying health coverage for all or part of a year that is commonly referred to as the "individual mandate." Additionally, on January 22, 2018, Trump signed acontinuing resolution on appropriations for fiscal year 2018 that delayed the implementation of certain PPACA-mandated fees, including the so-called "Cadillac" tax on certain high costemployer-sponsored insurance plans, the annual fee imposed on certain health insurance providers based on market share, and the medical device excise tax on non-exempt medical devices. Further, theBipartisan Budget Act of 2018, or the BBA, among other things, amends the PPACA, effective January 1, 2019, to close the coverage gap in most Medicare drug plans, commonly referred to as the"donut hole". Congress may consider other legislation to repeal or replace elements of the PPACA.

        Manyof the details regarding the implementation of the PPACA are yet to be determined, and at this time, the full effect that the PPACA would have on a pharmaceutical manufacturerremains unclear. In particular, there is uncertainty surrounding the applicability of the biosimilars provisions under the PPACA. The FDA has issued several guidance documents, and withdrew others,but no implementing regulations on biosimilars have been adopted. A number of biosimilar applications have been approved over the past few years. The regulations that are ultimately promulgated andtheir implementation are likely to have considerable impact on the way pharmaceutical manufacturers conduct their business and may require changes to current strategies. A biosimilar is a biologicalproduct that is highly similar to an approved drug notwithstanding minor differences in clinically inactive components, and for which there are no clinically meaningful differences between thebiological product and the approved drug in terms of the safety, purity, and potency of the product.

        Additionally,there has been heightened governmental scrutiny in the United States of pharmaceutical pricing practices in light of the rising cost of prescription drugs and biologics.Such scrutiny has resulted in several recent congressional inquiries and proposed and enacted federal and state legislation designed to, among other things, bring more transparency to product pricing,review the relationship between pricing and manufacturer patient programs, and reform government program reimbursement methodologies for products. At the federal level, the Trump administration'sbudget proposal for fiscal year 2019 contains further drug price control measures that could be enacted during the 2019 budget process or in other future legislation, including, for example, measuresto permit Medicare Part D plans to negotiate the price of certain drugs under Medicare Part B, to allow some states to negotiate drug prices under Medicaid, and to eliminate cost sharing for genericdrugs for low-income patients. Further, the Trump administration released a "Blueprint" to lower drug prices and reduce out of pocket costs of drugs that contains additional proposals to increase drugmanufacturer competition, increase the negotiating power of certain federal healthcare programs, incentivize manufacturers to lower the list price of their products and reduce the out of pocket costsof drug products paid by consumers. HHS has already started the process of soliciting feedback on some of these measures and, at the same, is immediately implementing others under its existingauthority. Although a number of these, and other potential, proposals will require authorization through additional legislation to become effective, Congress and the Trump administration have eachindicated that it will continue to seek new legislative and/or administrative measures to control drug costs. At the state level, legislatures have become increasingly aggressive in passinglegislation and implementing regulations designed to control pharmaceutical and biological product pricing, including price or patient reimbursement

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constraints,discounts, restrictions on certain product access, and marketing cost disclosure and transparency measures, and to encourage importation from other countries and bulk purchasing. Legallymandated price controls on payment amounts by third-party payors or other restrictions could harm a pharmaceutical manufacturer's business, results of operations, financial condition and prospects. Inaddition, regional healthcare authorities and individual hospitals are increasingly using bidding procedures to determine what pharmaceutical products and which suppliers will be included in theirprescription drug and other healthcare programs. This could reduce ultimate demand for certain products or put pressure product pricing, which could negatively affect a pharmaceutical manufacturer'sbusiness, results of operations, financial condition and prospects.

        Morerecently on May 30, 2018, the Trickett Wendler, Frank Mongiello, Jordan McLinn, and Matthew Bellina Right to Try Act of 2017 ("Right to Try Act") was signed into law. The law, amongother things, provides a federal framework for certain patients to access certain investigational new drug products that have completed a Phase I clinical trial and that are undergoinginvestigation for FDA approval. Under certain circumstances, eligible patients can seektreatment without enrolling in clinical trials and without obtaining FDA permission under an FDA expanded access program.

        Inaddition, given recent federal and state government initiatives directed at lowering the total cost of healthcare, Congress and state legislatures will likely continue to focus onhealthcare reform, the cost of prescription drugs and biologics and the reform of the Medicare and Medicaid programs. While no one cannot predict the full outcome of any such legislation, it mayresult in decreased reimbursement for drugs and biologics, which may further exacerbate industry-wide pressure to reduce prescription drug prices. This could harm a pharmaceutical manufacturer'sability to generate revenue. Increases in importation or re-importation of pharmaceutical products from foreign countries into the United States could put competitive pressure on a pharmaceuticalmanufacturer's ability to profitably price products, which, in turn, could adversely affect business, results of operations, financial condition and prospects. A pharmaceutical manufacturer mightelect not to seek approval for or market products in foreign jurisdictions in order to minimize the risk of re-importation, which could also reduce the revenue generated from product sales. It is alsopossible that other legislative proposals having similar effects will be adopted.

        Furthermore,regulatory authorities' assessment of the data and results required to demonstrate safety and efficacy can change over time and can be affected by many factors, such as theemergence of new information, including on other products, changing policies and agency funding, staffing and leadership. No one can be sure whether future changes to the regulatory environment willbe favorable or unfavorable to business prospects. For example, average review times at the FDA for marketing approval applications can be affected by a variety of factors, including budget andfunding levels and statutory, regulatory and policy changes.

Regulation in the European Union

        Biologics are also subject to extensive regulation outside of the U.S. In the EU, for example, there is a centralized approval procedure thatauthorizes marketing of a product in all countries of the EU, which includes most major countries in Europe. If this procedure is not used, approval in one country of the European Union can be used toobtain approval in another country of the EU under two simplified application processes, the mutual recognition procedure or the decentralized procedure, both of which rely on the principle of mutualrecognition. After receiving regulatory

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approvalthrough any of the European registration procedures, pricing and reimbursement approvals are also required in most countries.

Other Regulations

        We are also subject to numerous federal, state and local laws relating to such matters as safe working conditions, manufacturing practices,environmental protection, fire hazard control, and disposal of hazardous or potentially hazardous substances and biological materials. We may incur significant costs to comply with such laws andregulations now or in the future.

Reimbursement

        Obtaining coverage and reimbursement approval for a product from a government or other third-party payor is a time-consuming and costly processthat can require the provision of supporting scientific, clinical and cost effectiveness data for the use of drug or biologic products to the payor. There may be significant delays in obtaining suchcoverage and reimbursement for newly approved products, and coverage may be more limited than the purposes for which the product is approved by the FDA or similar regulatory authorities outside of theUnited States. Moreover, eligibility for coverage and reimbursement does not imply that a product will be paid for in all cases or at a rate that covers operating costs, including research,development, intellectual property, manufacture, sale and distribution expenses. Reimbursement rates may vary according to the use of the product and the clinical setting in which it is used, may bebased on reimbursement levels already set for lower cost products and may be incorporated into existing payments for other services. Net prices for products may be reduced by mandatory discounts orrebates required by government healthcare programs or private payors and by any future relaxation of laws that presently restrict imports of product from countries where they may be sold at lowerprices than in the U.S.

        Thereis significant uncertainty related to the insurance coverage and reimbursement of newly approved products. Third-party payors often rely upon Medicare coverage policy and paymentlimitations in setting their own reimbursement policies, but also have their own methods and approval process apart from Medicare coverage and reimbursement determinations. It is difficult to predictwhat third party payors will decide with respect to coverage and reimbursement for new drug and biologic product candidates. An inability to promptly obtain coverage and adequate reimbursement ratesfrom both government-funded and private payors for any approved products could have a material adverse effect on a pharmaceutical manufacturer's operating results, ability to raise capital needed tocommercialize products and overall financial condition.

        Reimbursementmay impact the demand for, and/or the price of, any product which obtains marketing approval. Even if coverage is obtained for a given product by a third-party payor, theresulting reimbursement payment rates may not be adequate or may require co-payments that patients find unacceptably high. Patients who are prescribed medications for the treatment of theirconditions, and their prescribing physicians, generally rely on third-party payors to reimburse all or part of the costs associated with those medications. Patients are unlikely to use products unlesscoverage is provided and reimbursement is adequate to cover all or a significant portion of the cost of the products. Therefore, coverage and adequate reimbursement is critical to new productacceptance. Coverage decisions may depend upon clinical and economic standards that disfavor

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newdrug products when more established or lower cost therapeutic alternatives are already available or subsequently become available.

        TheU.S. government, state legislatures and foreign governmental entities have shown significant interest in implementing cost containment programs to limit the growth of government-paidhealthcare costs, including price controls, restrictions on reimbursement and coverage and requirements for substitution of generic products for branded prescription drugs. Adoption of governmentcontrols and measures, and tightening of restrictive policies in jurisdictions with existing controls and measures, could exclude or limit our products from coverage and limit payments forpharmaceuticals.

        Inaddition, it is expected that the increased emphasis on managed care and cost containment measures in the United States by third-party payors and government authorities will continueand place further pressure on pharmaceutical pricing and coverage. Coverage policies and third-party reimbursement rates may change at any time. Even if favorable coverage and reimbursementstatus is attained for one or more drug products that gain regulatory approval, less favorable coverage policies and reimbursement rates may be implemented in the future.

Employees

        As of March 31, 2018, we had 25 full time employees, five part-time employees and several consultants. None of our employees are coveredby a collective bargaining agreement. We consider our relationship with our employees to be good.

Facilities

        Our corporate headquarters are located in San Jose, California, where we lease approximately 4,500 gross square feet of office and laboratoryspace under a lease that can be terminated with 90 days' notice.

        Webelieve that our facilities are adequate to meet our current needs, and that suitable additional alternative spaces will be available in the future on commercially reasonable terms,if required.

Legal Proceedings

        We are not currently a party to any legal proceedings. From time to time, we may be involved in legal proceedings or subject to claims incidentto the ordinary course of business. Regardless of the outcome, such proceedings or claims can have an adverse impact on us because of defense and settlement costs, diversion of resources and otherfactors, and there can be no assurances that favorable outcomes will be obtained.

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MANAGEMENT

Executive Officers and Directors

        Set forth below is certain information with respect to the individuals who are our directors and executive officers as of June 30, 2018:

        Eric Patzer, Ph.D, Executive Chairman of the Board of Directors (Class III).    Dr. Patzer is one of our co-founders. He wasappointedChairman in May 2014 and served as President from 2003 through 2014. Prior to that, he was VP of Development at Aviron Inc. from 1996 to 2002. Prior to that, he was VP of Product Development atGenentech from 1981 to 1996. Dr. Patzer received his B.S. in Mechanical Engineering from the Pennsylvania State University and his Ph.D. in Microbiology from University of Virginia. We believethat Dr. Patzer possesses specific attributes that qualify him to serve as a member of our board of directors, including his experience in managing projects through the entire developmentprocess to regulatory approval, his longevity in the industry, and his intimate knowledge of our company, as he is a founder.

        Isaac Blech, Vice Chairman of the Board of Directors (Class II).    Mr. Blech was appointed to the board of directors and as ourViceChairman in December 2015 pursuant to a verbal agreement between us and Mr. Blech. Mr. Blech is the co-founder and vice chairman of Sapience Therapeutics Inc., which he has been at since 2015.Mr. Blech is the co-founder and vice chairman of Elucida Oncology Inc., which he has been at since 2013. Mr. Blech is the co-founder and vice chairman at Centrexion Therapeutics Corp., which hehas been at since 2011. Mr. Blech is also the co-founder and vice chairman at Cerecor Inc., which he has been at since 2011. Mr. Blech currently serves as a director for Marina Biotech Inc., DiffusionPharmaceuticals Inc., Edge Therapeutics Inc., SpendSmart Networks Inc., ContraFect Corp. and InspireMD Inc. Mr. Blech is a successful founder and investor in the biotechnology industry. Overthe past thirty five years, he has established multiple successful biotechnology companies. These include Celgene Corporation, ICOS Corporation, Nova Pharmaceutical Corporation, PathogenesisCorporation and Genetics Systems Corporation. Mr. Blech earned a B.A. in Hebrew from Baruch College in 1975. We believe that Mr. Blech's business experience and ties to the investmentcommunity qualify him to serve as a member of our board of directors.

        Vu Truong, Ph.D, Chief Executive Officer, Chief Scientific Officer and Director (Class III).    Dr. Truong is one of ourco-founders andour Chief Executive Officer and Chief Scientific Officer. He has served as our Chief Executive Officer, Chief Scientific Officer and head of R&D since

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2003.He has more than 15 years of experience in biopharmaceutical drug development, having held positions of increasing responsibilities at Transform Pharmaceuticals Inc., GeneMedicine Inc.,Aviron Inc. and MedImmune (sold to AstraZeneca). He received his Ph.D. in Pharmacology and Molecular Sciences at the Johns Hopkins University School of Medicine and his B.A. in Biochemistry fromBrandeis University. We believe that Dr. Truong possesses specific attributes that qualify him to serve as a member of our board of directors, including his depth of scientific, operating,strategic, transactional, and senior management experience in our industry, his longevity in the industry, and his intimate knowledge of our company, as he is a founder.

        Fred Kurland, Chief Financial Officer.    Mr. Kurland has served as our Chief Financial Officer since July 2015 and served on ourboard ofdirectors from August 2014 through July 2015. He is a seasoned financial executive with 35 years of experience in the pharmaceutical industry. Prior to joining us he was the Vice President,Finance, Chief Financial Officer and Secretary of XOMA Corporation from December 2008 through March 2015. Between 2002 and 2008 Mr. Kurland served as Chief Financial Officer of BayhillTherapeutics, Inc., Corcept Therapeutics Inc. and Genitope Corp. From 1998 to 2002, he served as Senior Vice President and Chief Financial Officer of Aviron, which was acquired by MedImmune in2001. From 1996 to 1998, Mr. Kurland was Vice President and Chief Financial Officer of Protein Design Labs, Inc., an antibody design company, and from 1995 to 1996, he served as VicePresident and Chief Financial Officer of Applied Immune Sciences, Inc. He also held a number of financial management positions at Syntex Corporation, a pharmaceutical company acquired by Roche,including Vice President and Controller between 1991 and 1995. Mr. Kurland received his J.D. and M.B.A. from the University of Chicago and his B.S. in Business and Economics from LehighUniversity.

        Wolfgang Dummer, M.D., Ph.D, Chief Medical Officer.    Dr. Dummer was hired as our Chief Medical Officer in March 2018.Dr. Dummerhas more than 20 years of clinical trial and drug development experience, most recently as an independent executive consultant for various biotechnology companies since January 2017. FromJanuary 2012 to December 2016, he was Vice President of Clinical Development at BioMarin Pharmaceutical Inc., where he led the clinical development and approval of Vimizim (elosulfase alpha),now BioMarin's leading marketed compound. For 11 years prior, he held various senior roles in Clinical Research and Development at Genentech, Inc. He also spent three years studying atthe Scripps Research Institute in La Jolla, California. Dr. Dummer has authored and co-authored more than 50 peer-reviewed journal articles, and is a board-certified clinicaldermatologist and allergist/immunologist. He earned his Doktor der Medizin from the Technical University of Munich Medical School.

        Robert K. Coughlin, Director (Class II).    Mr. Coughlin was appointed to our board of directors in May 2014. Since September2007, he hasbeen the President and Chief Executive Officer of the Massachusetts Biotechnology Council, an association of more than 600 biotechnology companies, universities and academic institutions. He has spenthis career in both the public and private sectors, most recently serving as Undersecretary of Economic Development within Governor Deval Patrick's administration from January 2007 to August 2007.Prior to that, he was elected as State Representative to the 11^th Norfolk, Massachusetts district for three terms. He has held senior executive positions in the environmentalservices industry, capital management, and venture capital. He received his B.S. in Marine Engineering from the Massachusetts Maritime Academy. He has also been a lieutenant in the U.S. Naval Reservesince 1991. We believe that Mr. Coughlin possesses specific attributes that qualify him to serve as a member of our board of

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directors,including his experience in the industry, his familiarity with the Massachusetts life sciences centers and his advocacy for research and the biotechnology community.

        Craig Gibbs, Ph.D. Director (Class I).    Dr. Gibbs was appointed to our board of directors in April 2015. Since September 2015,Dr. Gibbshas been the Chief Business Officer at Forty Seven Inc. Dr. Gibbs served on the Board of Directors of Tobira Therapeutics from May 2013 to September 2016 and is an advisor to severalbiotechnology companies and venture capital firms. From 1992 to 2013, Dr. Gibbs worked for Gilead Sciences in a variety of leadership positions spanning Research, Corporate Development and,most recently, Vice President of Commercial Strategy/Commercial Planning and Operations. Prior to Gilead, Dr. Gibbs served as a Scientist in the Department of Protein Engineering atGenentech, Inc. He received his B.Sc. in Biochemistry from Massey University and his Ph.D. in Molecular Biology from the University of Glasgow in Scotland and his M.B.A. from Golden GateUniversity. We believe that Dr. Gibbs possesses specific attributes that qualify him to serve as a member of our board of directors, including extensive experience in the biotechnology industryand technical expertise in drug discovery and development.

        John Hamilton, Director (Class II).    Mr. Hamilton was appointed to our board of directors in June 2015. He served as a directorandaudit chair of three companies including Vermillion Inc. from2008 to 2013, Anesiva, Inc. during 2009 and Encompass Funds from 2012 to 2015. From 1997 until his retirement in 2007, Mr. Hamilton served as Vice President and Chief Financial Officerof Depomed, Inc., a specialty pharmaceutical company focused on enhancing pharmaceutical products. Prior to that, he was the Vice President and Chief Financial Officer at Glyko Inc. from May1992 to September 1996 and the Manager of Financial Planning and Analysis and then Treasurer at Chiron Corp. from September 1987 to May 1992. Mr. Hamilton began his career in internationalbanking with The Philadelphia National Bank and Crocker National Bank. Mr. Hamilton sits on the regional Board of Directors of the Association of Bioscience Financial Officers and ispast-president of the Treasurers Club of San Francisco. Mr. Hamilton received his M.B.A. from the University of Chicago and B.A. in International Relations from the University of Pennsylvania.We believe that Mr. Hamilton possesses specific attributes that qualify him to serve as a member of our board of directors, including the depth of his financial, accounting and operatingexperience.

        Robert R. Ruffolo, Jr., Ph.D., Director (Class II).    Dr. Ruffolo was appointed to our board of directors in April 2017. He hasprovidedmanagement, director and consulting services since 2008 as the President of Ruffolo Consulting LLC. Dr. Ruffolo currently serves on the Board of Directors of Diffusion Pharmaceuticals Inc. Heserved as the President of Research and Development and as the Corporate Senior Vice President of Wyeth Pharmaceuticals (now Pfizer) from 2000 through 2008. In these roles, he managed an R&Dorganization of 9,000 scientists with an annual budget in excess of $3 billion. From 2000 to 2002 he served as an Executive Vice President at Wyeth, where he was responsible for PharmaceuticalResearch and Development. Prior to joining Wyeth, Dr. Ruffolo spent 17 years at SmithKline Beecham Pharmaceuticals PLC (now GlaxoSmithKline) where he was Senior Vice President andDirector of Biological Sciences, Worldwide from 1984 to 2000. Before joining SmithKline Beecham, Dr. Ruffolo spent six years at Eli Lilly Co. from 1978 to 1984 where he was a SeniorPharmacologist. Dr. Ruffolo currently serves on the boards of directors of Sigilon Therapeutics Inc., Sapience Therapeutics Inc., Elucida Oncology Inc., and Trevena Inc. He received his B.S. inPharmacy from The Ohio State University

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andhis Ph.D. in Pharmacology from The Ohio State University. We believe that Dr. Ruffolo possesses specific attributes that qualify him to serve as a member of our board of directors,including his extensive experience in the pharmaceutical industry and technical and management expertise in drug discovery and development.

        Shawn Lu, Director (Class I).    Mr. Lu was appointed to our board of directors in December 2016. Mr. Lu has been theExecutiveDirector and Chief Financial Officer of Hepalink USA, Inc. since April 2014. Prior to that, he was the Area Manager at BMO Bank of Montreal from September 2013 to April 2014 and ResidentialMortgage Manager at The Toronto-Dominion Bank from January 2001 to September 2013. Mr. Lu currently serves as a director for Resverlogix Corp., Quest PharmaTech Inc. and Cantex Pharmaceuticals Inc.Prior to that, he was the Chief Financial Officer and Vice President of Corporate Finance of Shenzhen Hepalink Pharmaceutical Group Co. Ltd. from September 1999 to September 2000 and VP of CorporateFinance of Shenzhen FuTianXin Investment Co. Ltd. from February 1998 to August 1999. He received his B.S. in Engineering from Wuhan University of Transportation Technology and his M.B.A. from theZhongnan University of Economics. We believe that Mr. Lu possesses specific attributes that qualify him to serve as a member of our board of directors, including his experience in thepharmaceutical industry and the depth of his financial, accounting and operating experience.

Other Involvement in Certain Legal Proceedings

        None of our directors or executive officers has been involved in any bankruptcy or criminal proceedings, nor have there been any judgments orinjunctions brought against any of our directors or executive officers during the last ten years that we consider material to the evaluation of the ability and integrity of any director or executiveofficer.

Board Composition and Election of Directors

        Our board of directors currently consists of eight directors and we will have eight directors upon completion of this offering. Holders ofcommon stock have no cumulative voting rights in any election of directors.

        Thedirectors shall be classified with respect to the time for which they shall severally hold office by dividing them into three classes, Class I, Class II andClass III, each consisting as nearly as possible of one-third of the whole board. All directors shall hold office until their successors are elected and qualified, or until their earlier death,resignation, disqualification or removal. Class I Directors shall be elected for a term of one year; Class II Directors shall be elected for a term of two years; and Class IIIDirectors shall be elected for a term of three years; and at each annualstockholders' meeting thereafter, successors to the directors whose terms shall expire that year shall be elected to hold office for a term of three years, so that the term of office of one class ofdirectors shall expire in each year. Except in the event of vacancies in the board, directors shall be elected by a plurality of the votes cast at annual meetings of stockholders, and each director soelected shall hold office until the annual meeting at which their term expires and until his successor is duly elected and qualified, or until his earlier resignation or removal.

Director Independence

        Our board of directors has undertaken a review of the independence of each director. Based on information provided by each director concerninghis background, employment and affiliations,

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ourboard of directors has determined that Messrs. Coughlin, Ruffolo, Gibbs, Lu and Hamilton do not have a relationship that would interfere with the exercise of independent judgment incarrying out the responsibilities of a director and that each of these directors is "independent" as that term is defined under the listing standards of The Nasdaq Capital Market. In making thesedeterminations, our board of directors considered the current and prior relationships that each non-employee director has with our company and all other facts and circumstances our board of directorsdeemed relevant in determining their independence, including the beneficial ownership of our capital stock by each non-employee director, and the transactions involving them described in the sectiontitled "Certain Relationships and Related Party Transactions."

Board Committees

        Our board of directors has established an audit committee, a compensation committee, and a corporate governance/nominating committee, each ofwhich operates under a charter that has been approved by our board of directors.

        Ourboard of directors has determined that all of the members of the audit committee, the compensation committee and the nominating and corporate governance committee are independent asdefined under the applicable rules of The Nasdaq Capital Market, including, in the case of all of the members of our audit committee, the independence requirements contemplated by Rule 10A-3under the Exchange Act. In making such determination, the board of directors considered the relationships that each director has with our company and all other facts and circumstances that the boardof directors deemed relevant in determining director independence, including the beneficial ownership of our capital stock by each director.

        Thereare no family relationships among any of our directors or executive officers.

        Audit Committee.    Our audit committee is comprised of John Hamilton, Robert Coughlin and Craig Gibbs. Our board of directors hasdetermined that JohnHamilton is an audit committee financial expert, as defined by the rules of the SEC, and satisfies the financial sophistication requirements of applicable rules of The Nasdaq Capital Market.Mr. Hamilton is the chair of the audit committee.

        Ouraudit committee is authorized to, among other things:

•

monitor our financial reporting process and internal control system and complaints or concerns relating thereto;



•

recommend, for shareholder approval, the independent auditor to examine our accounts, controls and financial statements and select, evaluateand if necessary replace the independent auditor;



•

consider and approve, if appropriate, major changes to our accounting principles and practices as suggested by the independent auditors ormanagement;



•

establish regular and separate systems of reporting to the committee by management and the independent auditors regarding any significantjudgments made in management's preparation of the financial statements and the view of each as to appropriateness of such judgments and additional items as required under the Sarbanes-Oxley Actincluding critical accounting policies;

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•

review with the independent auditors and financial accounting personnel, the adequacy and effectiveness of our accounting and financialcontrols;



•

review the financial statements contained in the annual report and quarterly report to shareholders with management and the independentauditors;



•

review with management any financial information, earnings press releases and earnings guidance filed with the SEC or disseminated to thepublic; and



•

prepare the report of the audit committee that the rules of the SEC require to be included in our annual meeting proxy statement.

        Compensation Committee.    Our compensation committee is comprised of Robert Coughlin, Craig Gibbs and John Hamilton. Mr. Coughlin isthe chairof the compensation committee.

        Ourcompensation committee is authorized to:

•

review and recommend the compensation arrangements for management, including the compensation for our chief executive officer;



•

establish and review general compensation policies with the objective to attract and retain superior talent, to reward individual performanceand to achieve our financial goals;



•

administer our stock incentive plans; and



•

prepare the report of the compensation committee that the rules of the SEC require to be included in our annual meeting proxy statement.

        Corporate Governance/Nominating Committee.    Our corporate governance/nominating committee is comprised of Craig Gibbs, Robert Coughlinand JohnHamilton. Mr. Gibbs is the chair of the corporate governance/nominating committee.

        Ournominating and governance committee is authorized to:

•

identify and nominate members of the board of directors;



•

develop and recommend to the board of directors a set of corporate governance principles applicable to our company; and



•

oversee the evaluation of our board of directors.

Code of Business Conduct and Ethics

        Our board of directors has adopted a written Code of Business Conduct and Ethics applicable to our employees, officers and directors, includingthose officers responsible for financial reporting. The Code of Business Conduct and Ethics will be available on our website at www.aridispharma.com upon the completion of this offering. We expect thatany amendments to the code, or any waivers of its requirements, will bedisclosed on our website.

Director Compensation

        Directors who are employees do not receive any fees or other non-equity compensation for their service on our board of directors. Our board ofdirectors has granted equity awards from time to time to our non-employee directors as compensation for their service as directors. We also reimburse our non-employee directors for their reasonableout-of-pocket costs and travel expenses

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inconnection with their attendance at board of directors and committee meetings. Directors are also entitled to the protection provided by the indemnification provisions in our current certificate ofincorporation and bylaws, as well as the certificate of incorporation that will become effective immediately prior to completion of this offering. None of our non-employee directors received cashcompensation in 2017.

2018 Option Grants

        On January 26, 2018, we issued to Vu Truong the following stock options pursuant to our 2014 Equity Incentive Plan, which we referto as our 2014 Plan: 750,000 options with an exercise price of $2.65 and a vesting commencement date of December 5, 2017, and which vest in equal monthly installments over 48 months.

        OnMarch 29, 2018, we issued to Fred Kurland the following stock options pursuant to our 2014 Plan: (1) 42,624 fully-vested options with an exercise price of $2.68and (2) 25,575 options with anexercise price of $2.68 and a vesting commencement date of March 6, 2018, and which vest in equal monthly installments over 12 months. Additionally, on the same date, we granted 360,000 optionsto Wolfgang Dummer pursuant to our 2014 Plan, with an exercise price of $2.68 and a vesting commencement date of March 1, 2018, and which vest in equal monthly installments over48 months.

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EXECUTIVE AND DIRECTOR COMPENSATION

Summary Compensation Table

        The following table sets forth the compensation paid or accrued during the fiscal year ended December 31, 2017 to our Chief ExecutiveOfficer, Executive Chairman and Senior Vice President, Clinical, who were our named executive officers as of December 31, 2017.

Employment Agreements

        We do not have formal employment agreements with any of our named executive officers. We have entered into offer letter agreements andconfidentiality and invention assignment agreements with each of our named executive officers. Each named executive officer's employment is at will, and none of the offer letters provide for aspecific term or severance on a termination or change of control. Under the terms of our standard confidential information and invention assignment agreement, each executive has agreed (i) notto solicit our employees or consultants during his employment and for a period of one year after the termination of his employment, (ii) to protect our confidential and proprietary information,and (iii) to assign to us related intellectual property developed during the course of his employment. Each named executive officer is also eligible to participate in our standard employeebenefit plans.

        Thefollowing are descriptions of our offer letter agreements with our named executive officers. We currently expect to enter into formal employment agreements, the terms of which wehave not finalized, with our named executive officers prior to, or upon consummation of, this offering.

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Vu Truong, Ph.D.

        We entered into an offer letter agreement and confidential information and invention assignment agreement with Dr. Truong, our ChiefExecutive Officer and Chief Scientific Officer, on October 1, 2005. We paid Dr. Truong an annual base salary of $350,000 for the fiscal year ended December 31, 2017 and a 40%bonus. Dr. Truong's salary for 2018 was increased to $450,000 and his target annual bonus will be 45% of his salary.

Eric Patzer, Ph.D.

        We entered into an offer letter agreement and confidential information and invention assignment agreement with Dr. Patzer, our ExecutiveChairman, on October 15, 2005. During the year ended December 31, 2017, we paid Dr. Patzer an annual base salary of $275,000.

Alan Cohen, M.D.

        We entered into an offer letter agreement and confidential information and invention assignment agreement with Dr. Cohen, our Senior VicePresident, Clinical, on July 1, 2017. During the year ended December 31, 2017, we paid Dr. Cohen a monthly base salary of $15,000 per month. On March 26, 2018, we executeda new offer letter with Dr. Cohen which amends and supercedes his prior agreement with us. Under the terms of the new arrangement, Dr. Cohen will work on an hourly basis at a rate of$175 per hour. In addition, all stock options previously awarded but not yet vested as of March 26, 2018 were cancelled.

Wolfgang Dummer, M.D.,Ph.D.

        We entered into an offer letter agreement and confidential information and invention assignment agreement with Dr. Dummer, our ChiefMedical Officer, on February 5, 2018. As part of his agreement, he will be paid a salary of $390,000 and was paid a sign-on cash bonus of $30,000. We also agreed in the offer letter to workwith compensation consultants to provide recommendations for annual bonuses and severance packages for all senior executives moving going forward.

Outstanding Equity Awards At Fiscal Year-End

        The following table sets forth information for the named executive officers as of December 31, 2017 regarding the number of sharessubject to both exercisable and unexercisable stock options, as well as the exercise prices and expiration dates thereof, as of December 31, 2017. Except for the options set forth in the tablebelow, no other equity awards were held by any our

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namedexecutive officers as of December 31, 2017. All equity awards included below were granted from our 2014 Plan unless otherwise noted below.

401(k) plan

        We maintain a defined contribution employee retirement plan, or 401(k) plan, for our employees, effective as of October 1, 2016. Ournamed executive officers are eligible to participate in the 401(k) plan on the same basis as our other employees. The 401(k) plan is intended to qualify as a tax-qualified plan underSection 401(k) of the Internal Revenue Code. The 401(k) plan provides that each participant may make pre-tax deferrals from his or her compensation up to the statutory limit, which is $18,500for calendar year 2018, and other testing limits. Participants that are 50 years or older can also make "catch-up" contributions, which in calendar year 2018 may be up to an additional $6,000above the statutory limit. Although the 401(k) plan provides for

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discretionarymatching and profit sharing contributions, we currently do not make either type of contribution to the 401(k) plan. Participant contributions are held and invested, pursuant to theparticipant's instructions, by the plan's trustee.

2014 Equity Incentive Plan

        In May 2014, our board of directors approved the 2014 Plan. The 2014 Plan was most recently amended in September 2014. The 2014 Plan will expireon May 24, 2024. Under our 2014 Plan, we may grant incentive stock options, non-qualified stock options and restricted stock awards. As of June 30, 2018, there are 5,500,000 shares ofour common stock authorized for issuance under the 2014 Plan.

        Inaddition, the 2014 Plan contains an "evergreen" provision allowing for an annual increase in the number of shares of our common stock available for issuance under the plan on thefirst dayof each fiscal year beginning with fiscal year 2015. The annual increase in the number of shares shall be equal to the greater of:

•

500,000 shares of our common stock; or



•

such number of shares as is equal to the number of shares sufficient to cause the option pool to equal 20% of the issued and outstanding commonstock of the Company as of such date, provided, however, that if on any calculation date the number of shares equal to 20% of the total issued andoutstanding shares of common stock is less than the number of shares of common stock available for issuance under the 2014 Plan, no change will be made to the aggregate number of shares of commonstock issuable under the 2014 Plan for that year (such that the aggregate number of shares of common stock available for issuance under the 2014 Plan will never decrease).

        Theboard of directors has authorized our compensation committee to administer the 2014 Plan. In accordance with the provisions of the plan, the compensation committee will determine theterms of options and other awards. The compensation committee or the independent members of our board of directors will determine:

•

which employees, directors and consultants shall be granted options and other awards;



•

the number of shares of our common stock subject to options and other awards;



•

the exercise price of each option, which generally shall not be less than fair market value on the date of grant;



•

the schedule upon which options become exercisable;



•

the termination or cancellation provisions applicable to options;



•

the terms and conditions of other awards, including conditions for repurchase, termination or cancellation, issue price and repurchase price;and



•

all other terms and conditions upon which each award may be granted in accordance with the 2014 Plan.

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        Upona change of control, the administrator of the 2014 Plan, or the board of directors of any corporation assuming its obligations, may, in its sole discretion, take any one or more ofthe following actions pursuant to our plan, as to some or all outstanding awards:

•

make an appropriate and equitable adjustment in the number and kind of shares reserved for issuance under the 2014 Plan and in the number andoption price of shares subject to outstanding options granted under the 2014 Plan, to the end that after such event each optionee's proportionate interest shall be maintained (to the extent possible)as immediately before the occurrence of such event; and



•

to the extent feasible, make such other adjustments as may be required under the tax laws so that any Incentive Options previously grantedshall not be deemed modified within the meaning of Section 424(h) of the Code; appropriate adjustments shall also be made in the case of outstanding Restricted Stock granted under the Plan.

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CERTAIN RELATIONSHIPS AND RELATED PERSON TRANSACTIONS

        There are no transactions or series of similar transactions, since January 1, 2015 to which we have been a participant inwhich the amount involved exceeded or will exceed $120,000 and in which any of our director, executive officer, holder of more than 5% of our capital stock, promotor or certain control person or anymember of their immediate family had or will have a direct or indirect material interest.

Indemnification Agreements

        In connection with this offering, we will enter into indemnification agreements with each of our directors and executive officers. Theseindemnification agreements will provide the directors and executive officers with contractual rights to indemnification and expense advancement that are, in some cases, broader than the specificindemnification provisions contained under Delaware law.

Related Person Transaction Policy

        Prior to this offering, we have not had a formal policy regarding approval of transactions with related parties. We expect to adopt a relatedperson transaction policy that sets forth our procedures for the identification, review, consideration and approval or ratification of related person transactions. The policy will become effectiveimmediately upon the execution of the underwriting agreement for this offering. For purposes of our policy only, a related person transaction is a transaction, arrangement or relationship, or anyseries of similar transactions, arrangements or relationships, in which we and any related person are, were or will be participants in which the amount involved exceeds $120,000. Transactionsinvolving compensation for services provided to us as an employee or director are not covered by this policy. A related person is any executive officer, director or beneficial owner of more than 5% ofany class of our voting securities, including any of their immediate family members and any entity owned or controlled by such persons.

        Underthe policy, if a transaction has been identified as a related person transaction, including any transaction that was not a related person transaction when originally consummated orany transaction that was not initially identified as a related person transaction prior to consummation, our management must present information regarding the related person transaction to our auditcommittee, or, if audit committee approval would be inappropriate, to another independent body of our board of directors, for review, consideration and approval or ratification. The presentation mustinclude a description of, among other things, the material facts, the interests, direct and indirect, of the related persons, the benefits to us of the transaction and whether the transaction is onterms that are comparable to the terms available to or from, as the case may be, an unrelated third party or to or from employees generally. Under the policy, we will collect information that we deemreasonably necessary from each director, executive officer and, to the extent feasible, significant shareholder to enable us to identify any existing or potential related-person transactionsand to effectuate the terms of the policy. In addition, under our Code of Conduct, our employees and directors will have an affirmative responsibility to disclose any transaction or relationship thatreasonably could be expected to give rise to a conflict of interest. In considering related person transactions, our audit committee, or other independent body of our

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boardof directors, will take into account the relevant available facts and circumstances including, but not limited to:

•

the risks, costs and benefits to us;



•

the impact on a director's independence in the event that the related person is a director, immediate family member of a director or an entitywith which a director is affiliated;



•

the availability of other sources for comparable services or products; and



•

the terms available to or from, as the case may be, unrelated third parties or to or from employees generally.

        Thepolicy requires that, in determining whether to approve, ratify or reject a related person transaction, our audit committee, or other independent body of our board of directors, mustconsider, in light of known circumstances, whether the transaction is in, or is not inconsistent with,our best interests and those of our shareholders, as our audit committee, or other independent body of our board of directors, determines in the good faith exercise of its discretion.

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PRINCIPAL STOCKHOLDERS

        The following table sets forth information regarding the beneficial ownership of our common stock as of June 30, 2018 andas adjusted to reflect the sale of our common stock offered by this prospectus, by:

•

our named executive officers;



•

each of our directors;



•

all of our current directors and executive officers as a group; and



•

each stockholder known by us to own beneficially more than five percent of our common stock

        Beneficialownership is determined in accordance with the rules of the SEC and includes voting or investment power with respect to the securities. Shares of common stock that may beacquired by an individual or group within 60 days of June 30, 2018, pursuant to the exercise of convertible securities, are deemed to be outstanding for the purpose of computing thepercentage ownership of such individual or group, but are not deemed to be outstanding for the purpose of computing the percentage ownership of any other person shown in the table. Percentage ofownership is based on an aggregate of 37,263,883 shares of common stock, assuming the automatic conversion of the Series A convertible preferred stock into an aggregate of 36,196,193 upon theclosing of this offering.

        Exceptas indicated in footnotes to this table, we believe that the stockholders named in this table have sole voting and investment power with respect to all shares of common stockshown to be beneficially owned by them, based on information provided to us by such stockholders. Unless

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otherwiseindicated, the address for each director and executive officer listed is: c/o Aridis Pharmaceuticals, Inc., 5941 Optical Ct. #200, San Jose, California 95138.

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DESCRIPTION OF CAPITAL STOCK

General

        Upon completion of this offering, our authorized capital stock will consist of 100,000,000 shares of common stock, par value $0.0001 per share,and 60,000,000 shares of preferred stock, par value $0.0001 per share. The following description of our capital stock and provisions of our certificate of incorporation and bylaws is only a summary.You should also refer to our certificate of incorporation, a copy of which is incorporated by reference as an exhibit to the registration statement of which this prospectus is a part, and our bylaws,a copy of which is incorporated by reference as an exhibit to the registration statement of which this prospectus is a part.

Common Stock

        As of March 31, 2018, there were 37,263,883 shares of our common stock outstanding and held by over 200 stockholders, assuming theautomatic conversion of all outstanding shares of our Series A convertible preferred stock into an aggregate of 36,196,193 shares of our common stock upon the closing of this offering.

        Voting Rights.    Each holder of Common Stock is entitled to one vote for each share of Common Stock on all matters submitted to a vote ofthestockholders, including the election of directors. Our certificate of incorporation and bylaws do not provide for cumulative voting. Because of this, the holders of a majority of the shares of CommonStock entitled to vote in any election of directors can elect all of the directors standing for election, subject to the rights of holders of any then outstanding shares of Preferred Stock.

        Dividends.    Subject to preferences that may be applicable to any then outstanding Preferred Stock, the holders of Common Stock areentitled to receivedividends, if any, as may be declared from time to time by our Board of Directors out of legally available funds.

        Liquidation.    In the event of our liquidation, dissolution or winding up or an event of sale (as defined in our certificate ofincorporation), holdersof Common Stock will be entitled to share ratably in the net assets legally available for distribution to stockholders after the payment of all of our debts and other liabilities, subject to thesatisfaction of any liquidation preference granted to the holders of any then outstanding shares of Preferred Stock.

        Rights and Preferences.    Holders of Common Stock have no preemptive, conversion or subscription rights, and there are no redemption orsinking fundprovisions applicable to our Common Stock. The rights, preferences and privileges of the holders of Common Stock are subject to, and may be adversely affected by, the rights of the holders of sharesof any series of Preferred Stock that we may designate and issue in the future.

Preferred Stock

        We are authorized to issue up to a total of 60,000,000 shares of preferred stock, par value $0.0001 per share, without stockholder approval. Thepreferred stock, subject to limitations prescribed by Delaware law, may be issued in one or more series, as determined by our board of directors. The board of directors shall have the power toestablish the number of shares to be included in each series and to fix the designation, powers, preferences and rights of the shares of

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eachseries and any of its qualifications, limitations or restrictions. Our board of directors also can increase or decrease the number of shares of any series, but not below the number of shares ofthat series then outstanding, without any further vote or action by our stockholders. Our board of directors may authorize the issuance of preferred stock with voting or conversion rights that couldadversely affect the voting power or other rights of the holders of the common stock. The issuance of preferred stock, while providing flexibility in connection with possible acquisitions and othercorporate purposes, could, among other things, have the effect of delaying, deferring or preventinga change in control of our company and may adversely affect the market price of our common stock and the voting and other rights of the holders of our common stock.

Series A Convertible Preferred Stock

        In July 2014, we filed with the Secretary of State of the State of Delaware a certificate of designation for the Series A convertiblepreferred stock, setting forth the rights, powers, and preferences of the Series A preferred stock. Pursuant to the certificate of designation, we designated 8,828,020 shares as Series Aconvertible preferred stock. In July 2014 we converted the 8,828,020 common shares on a one for one basis into shares of Series A convertible preferred stock. Each share of Series Apreferred stock is entitled to voting rights equivalent to the number of shares of common stock into which each share can be converted. Each of Series A convertible preferred stock isconvertible at the holder's option at any time into common stock on a one for one basis and conversion is automatic upon the closing of an underwritten public offering at an issuance price of $4.10per share. Upon the liquidation, dissolution or winding up of our business, each holder shall be entitled to receive, for each share of Series A preferred stock, out of our assets legallyavailable therefore, a preferential amount in cash equal to $2.05 per share. If upon any such distribution our assets shall be insufficient to pay the holders of the outstanding shares ofSeries A convertible preferred stock the full amounts to which they are entitled, such holders shall share ratably in any distribution of assets in accordance with the sums which would bepayable on such distribution if all sums payable thereon were paid in full. Any remaining assets or funds available for distribution to stockholders shall be distributed among the holders ofSeries A preferred stock and common stock pro rata based on the number of shares of common stock held by each (assuming conversion of all such Series A convertible preferred stock andconvertible common stock, if any, according to their respective terms). Holders of the preferred stock, in preference to the holders of common stock, are entitled to receive dividends, when and ifdeclared by the Board of Directors, but only out of funds legally available. 16,516,606 shares sold at $2.05 per share and 2,033,898 shares sold at $2.95 per share contain price based anti-dilutionprotection rights. Unless agreed to otherwise, if we issue additional securities at a purchase price less than the purchase price paid by these respective holders, we shall issue additional preferredshares equal to the difference of the number of preferred shares that each respective shareholder would have received if they paid the subsequent lower price, and the number of share each respectiveshareholder originally received.

Consent of Series A Convertible Preferred Stock Holders

        In connection with this offering, the holders of a majority of the Series A Convertible Preferred Stock approved the mandatory conversionof the Series A Preferred into shares of common stock upon completion of this offering. Upon completion of this offering we shall have no outstanding shares of preferred stock.

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Anti-Takeover Effects of Provisions of Delaware State Law

        We are governed by the provisions of Section 203 of the Delaware General Corporation Law. In general, Section 203 prohibits apublic Delaware corporation from engaging in a "business combination" with an "interested stockholder" for a period of three years after the date of the transaction in which the person became aninterested stockholder, unless:

•

the transaction was approved by the board of directors prior to the time that the stockholder became an interested stockholder;



•

upon consummation of the transaction which resulted in the stockholder becoming an interested stockholder, the interested stockholder owned atleast 85% of the voting stock of the corporation outstanding at the time the transaction commenced, excluding shares owned by directors who are also officers of the corporation and shares owned byemployee stock plans in which employee participants do not have the right to determine confidentially whether shares held subject to the plan will be tendered in a tender or exchange offer; or



•

at or subsequent to the time the stockholder became an interested stockholder, the business combination was approved by the board of directorsand authorized at an annual or special meeting of the stockholders, and not by written consent, by the affirmative vote of at least two-thirds of the outstanding voting stock which is not owned by theinterested stockholder.

        Ingeneral, Section 203 defines a "business combination" to include mergers, asset sales and other transactions resulting in financial benefit to a stockholder and an "interestedstockholder" as a person who, together with affiliates and associates, owns, or within three years did own, 15% or more of the corporation's outstanding voting stock. These provisions may have theeffect of delaying, deferring or preventing changes in control of our company.

        Ourcertificate of incorporation and our bylaws include a number of provisions that could deter hostile takeovers or delay or prevent changes in control of our board of directors ormanagement team, including the following:

        Board of Directors Vacancies.    Our bylaws authorize only our board of directors to fill vacant directorships, including newly createdseats. Inaddition, the number of directors constituting our board of directors will be permitted to be set only by a resolution adopted by a majority vote of our entire board of directors. These provisionswould prevent a stockholder from increasing the size of our board of directors and then gaining control of our board of directors by filling the resulting vacancies with its own nominees. This willmake it more difficult to change the composition of our board of directors and will promote continuity of management.

        Classified Board.    Our bylaws provide that our board of directors is classified into three classes of directors. A third party may bediscouraged frommaking a tender offer or otherwise attempting to obtain control of us as it is more difficult and time consuming for stockholders to replace a majority of the directors on a classified board ofdirectors. See the section titled "Management — Classified Board of Directors."

        Stockholder Action; Special Meeting of Stockholders.    Our bylaws provide that any action which may be taken at any annual or specialmeeting ofstockholders, may, if such action has been earlier approved by the Board, be taken without a meeting.

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        Asa result, a holder controlling a majority of our capital stock would not be able to amend our bylaws or remove directors without holding a meeting of our stockholders called inaccordance with our bylaws unless such action had been earlier approved by the Board. Our bylaws further provide that special meetings of our stockholders may be called only by our board of directorsor the chairman of our board of directors, thus prohibiting a stockholder from calling a special meeting. These provisions might delay the ability of our stockholders to force consideration of aproposal or for stockholders controlling a majority of our capital stock to take any action, including the removal of directors.

        Advance Notice Requirements for Stockholder Proposals and Director Nominations.    Our bylaws provide advance notice procedures forstockholders seekingto bring business before our annual meeting of stockholders or to nominate candidates for election as directors at our annual meeting of stockholders. Our bylaws will also specify certain requirementsregarding the form and content of a stockholder's notice. These provisions might preclude our stockholders from bringing matters before our annual meeting of stockholders or from making nominationsfor directors at our annual meeting of stockholders if the proper procedures are not followed. We expect that these provisions may also discourage or deter a potential acquirer from conducting asolicitation of proxies to elect the acquirer's own slate of directors or otherwise attempting to obtain control of our company.

        No Cumulative Voting.    The Delaware General Corporation Law provides that stockholders are not entitled to cumulate votes in theelection of directorsunless a corporation's certificate of incorporation provides otherwise. Our certificate of incorporation does not provide for cumulative voting.

        Issuance of Undesignated Preferred Stock.    Our board of directors will have the authority, without further action by our stockholders,to issue up to20,000,000 shares of undesignated preferred stock with rights and preferences, including voting rights, designated from time to time by our board of directors. The existence of authorized but unissuedshares of preferred stock would enable our board of directors to render more difficult or to discourage an attempt to obtain control of us by means of a merger, tender offer, proxy contest or othermeans.

Warrants

May 2014 Warrants

        In May 2014, in connection with the May 2014 convertible notes, we issued warrants to purchase shares of common stock in the aggregate value of$3,500,000 at a price and quantity that is dependent on future events. If, prior to the first anniversary date of the warrants, an initial public offering, or IPO, is consummated the exercise pricewill be the issuance price first offered in the IPO. If an IPO is not consummated prior to the first anniversary date the exercise price will be determined by dividing (a) $40.0 million,by (b) the aggregate number of outstanding shares of common stock on the first anniversary (assuming the full conversion, exercise or exchange of all securities outstanding on the firstanniversary convertible into, exercisable or exchangeable for, shares of common stock). Upon the conversion of the May 2014 convertible notes on May 31, 2015, the exercise price of the warrantswas set at $4.40 per share. The number of shares issuable upon exercise of the warrants was 795,816.

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        Ifat any time while these warrants are exercisable a registration statement covering the resale of these warrants are not effective with the SEC and the fair value of one warrant shareis greater than the exercise price (at the date of calculation), the warrant holder may, in his sole discretion, exercise all or any part of the warrant in a "cashless" or "net-issue" exercise.

August 2014 Warrants

        On August 12, 2014 we issued warrants to purchase shares of our common stock that are exercisable any time prior to the third anniversaryof the date of issuance. The number of shares of common stock issuable upon the exercise of the three year warrants will be equal to $3,250,000 divided by either (i) the per share price atwhich the common stock is first offered to the public in an underwritten public offering if such underwritten public offering is consummated on or before August 12, 2015 or (ii) if nosuch offering is consummated on or before August 12, 2015, the quotient obtained by dividing (a) $50 million, by (b) the aggregate number of outstanding shares of commonstock on August 12, 2015 (assuming the full conversion, exercise or exchange of all securities outstanding on such date convertible into, exercisable or exchangeable for, shares of commonstock, other than the notes issued in our August 12, 2014 private placement). The exercise price is subject to adjustment in certain circumstances. Upon the conversion of the August 2014convertible notes on August 12, 2015, the exercise price of the warrants was set at $5.03 per share. The number of shares issuable upon exercise of the warrants was 645,723.

        Ifat any time while these warrants are exercisable a registration statement covering the resale of these warrants are not effective with the SEC and the fair value of one warrant shareis greater than the exercise price (at the date of calculation), the warrant holder may, in his sole discretion, exercise all or any part of the warrant in a "cashless" or "net-issue" exercise.

        OnAugust 12, 2017, all August 2014 warrants expired unexercised.

December 2015 Warrants

        In December 2015, in connection with the December 2015 convertible notes offering, the Company issued warrants to purchase shares of commonstock in the aggregate value of $3,750,000 at a price and quantity that is dependent on future events. If, prior to the first anniversary date of the warrants, an IPO is consummated the exercise pricewill be the issuance price first offered in the IPO. If an IPO is not consummated prior to the first anniversary date the exercise price will be determined by dividing (a) $60.0 million,by (b) the aggregate number of outstanding shares of common stock on the first anniversary (assuming the full conversion, exercise or exchange of all securities outstanding on the firstanniversary convertible into, exercisable or exchangeable for, shares of common stock). Upon the conversion of the December 2015 convertible notes on December 15, 2016, the exercise price ofthe warrants was set at $2.35 per share. The number of shares issuable upon exercise of the warrants was 1,594,361.

        Ifat any time while these warrants are exercisable a registration statement covering the resale of these warrants are not effective with the SEC and the fair value of one warrant shareis greater than the exercise price (at the date of calculation), the warrant holder may, in his sole discretion, exercise all or any part of the warrant in a "cashless" or "net-issue" exercise.

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Transfer Agent and Registrar

        The transfer agent and registrar for our common stock is Philadelphia Stock Transfer, Inc. The transfer agent and registrar's address is2320 Haverford Rd., Suite 230, Ardmore, PA 19003.

Stock Market Listing

        We have applied to list our shares of common stock for listing on The Nasdaq Capital Market under the symbol "ARDS."

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SHARES ELIGIBLE FOR FUTURE SALE

        Prior to this offering, there has been no public market for our common stock, and a liquid trading market for our common stockmay not develop or be sustained after this offering. Future sales of substantial amounts of our common stock in the public market, or the anticipation of these sales, could materially and adverselyaffect market prices prevailing from time to time, and could impair our ability to raise capital through sales of equity or equity-related securities.

        Onlya limited number of shares of our common stock will be available for sale in the public market for a period of several months after completion of this offering due to contractualand legal restrictions on resale described below. Nevertheless, sales of a substantial number of shares of our common stock in the public market after such restrictions lapse, or the perception thatthose sales may occur, could materially and adversely affect the prevailing market price of our common stock. Although we have applied to list our common stock on The Nasdaq Capital Market we cannotassure you that there will be an active market for our common stock.

        Ofthe shares to be outstanding immediately after the completion of this offering, we expect that the            shares to be sold in this offering will be freely tradable withoutrestriction under the Securities Act unless purchased by our "affiliates," as that term is defined in Rule 144 under the Securities Act. The remaining            shares of our commonstockoutstanding after this offering will be"restricted securities" under Rule 144, and we expect that            of these restricted securities will be subject to the 180-day lock-up period under the lock-up agreements asdescribedbelow. These restricted securities may be sold in the public market only if registered or pursuant to an exemption from registration, such as Rule 144 or Rule 701 under the SecuritiesAct.

Rule 144

        In general, under Rule 144 as currently in effect, once we have been subject to the public company reporting requirements ofSection 13 or Section 15(d) of the Exchange Act for at least 90 days, a person who is not deemed to have been one of our affiliates for purposes of the Securities Act at any timeduring the 90 days preceding a sale and who has beneficially owned the shares of our common stock proposed to be sold for at least six months is entitled to sell those shares without complyingwith the manner of sale, volume limitation or notice provisions of Rule 144, subject to compliance with the public information requirements of Rule 144. If such a person has beneficiallyowned the shares proposed to be sold for at least one year, including the holding period of any prior owner other than our affiliates, then that person would be entitled to sell those shares withoutcomplying with any of the requirements of Rule 144.

        Ingeneral, under Rule 144, as currently in effect, our affiliates or persons selling shares of our common stock on behalf of our affiliates are entitled to sell upon expirationof the market standoff agreements and lock-up agreements described above, within any three-month period, a number of shares that does not exceed the greaterof:

•

1% of the number of shares of our capital stock then outstanding, which will equal            shares immediately after this offering; or



•

the average weekly trading volume of our common stock during the four calendar weeks preceding the filing of a notice on Form 144 withrespect to that sale.

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        Salesunder Rule 144 by our affiliates or persons selling shares of our common stock on behalf of our affiliates are also subject to certain manner of sale provisions and noticerequirements and to the availability of current public information about us.

Rule 701

        Rule 701 generally allows a stockholder who purchased shares of our common stock pursuant to a written compensatory plan or contract andwho is not deemed to have been an affiliate of ours during the immediately preceding 90 days to sell these shares in reliance upon Rule 144, but without being required to comply with thepublic information, holding period, volume limitation, or notice provisions of Rule 144. Rule 701 also permits affiliates of ours to sell their Rule 701 shares underRule 144 without complying with the holding period requirements of Rule 144. All holders of Rule 701 shares, however, are required to wait until 90 days after the date ofthis prospectus before selling such shares pursuant to Rule 701 and until expiration of the 180-day lock-up period described below.

Lock-Up Agreements

        In connection with this offering, we, our officers and directors, and our other shareholders, have agreed to a 180 day "lock-up" periodfrom the closing of this offering, with respect to the shares that they beneficially own, including shares issuable upon the exercise of convertible securities and options that are currentlyoutstanding or which may be issued. This means that, for a period of 180 days following the closing of this offering, such persons may not offer, sell, pledge or otherwise dispose of thesesecurities without the prior written consent of the underwriters. The 180 day restricted period is subject to extension upon certain events and the terms of the lock-up agreements may be waivedat the underwriters' discretion. The lock-up restrictions, specified exceptions and the circumstances under which the 180-day lock-up period may be extended are described in more detail under"Underwriting."

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MATERIAL U.S. FEDERAL INCOME TAX CONSEQUENCES TO
NON-U.S. HOLDERS OF OUR COMMON STOCK

        The following is a summary of the material U.S. federal income tax consequences to non-U.S. holders (as defined below) of theownership and disposition of our common stock but does not purport to be a complete analysis of all the potential tax considerations relating thereto. This summary is based upon the provisions of theInternal Revenue Code of 1986, as amended, or the Internal Revenue Code, Treasury regulations promulgated thereunder, administrative rulings and judicial decisions, all as of the date hereof. Theseauthorities may be changed, possibly retroactively, so as to result in U.S. federal income taxconsequences different from those set forth below. No ruling on the U.S. federal, state, or local tax considerations relevant to our operations or to the purchase, ownership or disposition of ourshares, has been requested from, the Internal Revenue Service, or the IRS, or other tax authority. No assurance can be given that the IRS would not assert, or that a court would not sustain, aposition contrary to any of the tax consequences described below.

        Thissummary also does not address the tax considerations arising under the laws of any non-U.S., state or local jurisdiction, or under U.S. federal gift and estate tax laws, except tothe limited extent set forth below. In addition, this discussion does not address tax considerations applicable to an investor's particular circumstances or to investors that may be subject to specialtax rules, including, without limitation:

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banks, insurance companies or other financial institutions, regulated investment companies or real estate investment trusts;



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persons subject to the alternative minimum tax or Medicare contribution tax on net investment income;



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tax-exempt organizations or governmental organizations;



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controlled foreign corporations, passive foreign investment companies and corporations that accumulate earnings to avoid U.S. federal incometax;



•

brokers or dealers in securities or currencies;



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traders in securities that elect to use a mark-to-market method of accounting for their securities holdings;



•

persons that own, or are deemed to own, more than five percent of our capital stock (except to the extent specifically set forth below);



•

U.S. expatriates and certain former citizens or long-term residents of the United States;



•

partnerships or entities classified as partnerships for U.S. federal income tax purposes or other pass-through entities (and investorstherein);



•

persons who hold our common stock as a position in a hedging transaction, "straddle," "conversion transaction" or other risk reductiontransaction or integrated investment;



•

persons who hold or receive our common stock pursuant to the exercise of any employee stock option or otherwise as compensation;

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•

persons who do not hold our common stock as a capital asset within the meaning of Section 1221 of the Internal Revenue Code; or



•

persons deemed to sell our common stock under the constructive sale provisions of the Internal Revenue Code.

        Inaddition, if a partnership or entity classified as a partnership for U.S. federal income tax purposes holds our common stock, the tax treatment of a partner generally will depend onthe status of the partner and upon the activities of the partnership. Accordingly, partnerships that hold our common stock, and partners in such partnerships, should consult their tax advisors.

        You are urged to consult your tax advisor with respect to the application of the U.S. federal income tax laws to your particular situation, as well as any taxconsequences of the purchase, ownership and disposition of our common stock arising under the U.S. federal estate or gift tax rules or under the laws of any state, local, non-U.S., or other taxingjurisdiction or under any applicable tax treaty.

Non-U.S. Holder Defined

        For purposes of this discussion, you are a non-U.S. holder (other than a partnership) if you are any holder otherthan:

•

an individual citizen or resident of the United States (for U.S. federal income tax purposes);



•

a corporation or other entity taxable as a corporation created or organized in the United States or under the laws of theUnited States, any state thereof, or the District of Columbia, or other entity treated as such for U.S. federal income tax purposes;



•

an estate whose income is subject to U.S. federal income tax regardless of its source; or



•

a trust (x) whose administration is subject to the primary supervision of a U.S. court and which has one or more "U.S. persons" (withinthe meaning of Section 7701(a)(30) of the Internal Revenue Code) who have the authority to control all substantial decisions of the trust or (y) which has made a valid election to betreated as a U.S. person.

Distributions

        As described in "Dividend Policy," we have never declared or paid cash dividends on our common stock and do not anticipate paying any dividendson our common stock in the foreseeable future. However, if we do make distributions on our common stock, those payments will constitute dividends for U.S. tax purposes to the extent paid from ourcurrent or accumulated earnings and profits, as determined under U.S. federal income tax principles. To the extent those distributions exceed both our current and our accumulated earnings and profits,they will constitute a return of capital and will first reduce your basis in our common stock, but not below zero, and then will be treated as gain from the sale of stock as described below under"— Gain on Disposition of Common Stock."

        Subjectto the discussion below on effectively connected income, backup withholding and foreign accounts, any dividend paid to you generally will be subject to U.S. withholding taxeither at a rate of 30% of the gross amount of the dividend or such lower rate as may be specified by an

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applicableincome tax treaty. In order to receive a reduced treaty rate, you must provide us with an IRS Form W-8BEN, IRS Form W-8BEN-E or other appropriate version of IRSForm W-8 certifying qualification for the reduced rate. A non-U.S. holder of shares of our common stock eligible for a reduced rate of U.S. withholding tax pursuant to an income tax treaty mayobtain a refund of any excess amounts withheld by timely filing an appropriate claim for refund with the IRS. If the non-U.S. holder holds the stock through a financial institution or other agentacting on the non-U.S. holder's behalf, the non-U.S. holder will be required to provide appropriate documentation to the agent, which then will be required to provide certification to us or our payingagent, either directly or through other intermediaries.

        Dividendsreceived by you that are effectively connected with your conduct of a U.S. trade or business (and, if required by an applicable income tax treaty, attributable to a permanentestablishment maintained by you in the United States) are generally exempt from such withholding tax. In order to obtain this exemption, you must provide us with an IRS Form W-8ECI or otherapplicable IRS Form W-8 properly certifying such exemption. Such effectively connected dividends, although not subject to withholding tax, are taxed at the same graduated rates applicable toU.S. persons, net of certain deductions and credits. In addition, if you are a corporate non-U.S. holder, dividends you receive that are effectively connected with your conduct of a U.S. trade orbusiness may also be subject to a branch profits tax at a rate of 30% or such lower rate as may be specified by an applicable income tax treaty. You should consult your tax advisor regarding anyapplicable tax treaties that may provide for different rules.

Gain on Disposition of Common Stock

        Subject to the discussion below regarding backup withholding and foreign accounts, you generally will not be required to pay U.S. federal incometax on any gain realized upon the sale or other disposition of our common stock unless:

•

the gain is effectively connected with your conduct of a U.S. trade or business (and, if required by an applicable income tax treaty, the gainis attributable to a permanent establishment maintained by you in the United States);



•

you are a non-resident alien individual who is present in the United States for a period or periods aggregating 183 days or more duringthe taxable year in which the sale or disposition occurs and certain other conditions are met; or



•

our common stock constitutes a United States real property interest by reason of our status as a "United States real property holdingcorporation," or USRPHC, for U.S. federal income tax purposes at any time within the shorter of (i) the five-year period preceding your disposition of our common stock, or (ii) yourholding period for our common stock.

        Webelieve that we are not currently and will not become a USRPHC for U.S. federal income tax purposes, and the remainder of this discussion so assumes. However, because thedetermination of whether we are a USRPHC depends on the fair market value of our U.S. real property relative to the fair market value of our other business assets, there can be no assurance that wewill not become a USRPHC in the future. Even if we become a USRPHC, however, as long as our common stock is regularly traded on an established securities market, such common stock will be treated asU.S. real property interests only if you actually or constructively hold more

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thanfive percent of such regularly traded common stock at any time during the shorter of the five-year period preceding your disposition of, or your holding period for, our common stock.

        Ifyou are a non-U.S. holder described in the first bullet above, you will be required to pay tax on the net gain derived from the sale under regular graduated U.S. federal income taxrates, and a corporate non-U.S. holder described in the first bullet above also may be subject to the branch profits tax at a 30% rate, or such lower rate as may be specified by an applicable incometax treaty. If you are an individual non-U.S. holder described in the second bullet above, you will be required to pay a flat 30% tax (or such lower rate specified by an applicable income tax treaty)on the gain derived from the sale, which gain may be offset by U.S. source capital losses for the year (provided you have timely filed U.S. federal income tax returns with respect to such losses). Youshould consult any applicable income tax or other treaties that may provide for different rules.

Federal Estate Tax

        Our common stock beneficially owned by an individual who is not a citizen or resident of the United States (as defined for U.S. federal estatetax purposes) at the time of their death will generally be includable in the decedent's gross estate for U.S. federal estate tax purposes, unless an applicable estate tax treaty provides otherwise.The test for whether an individual is a resident of the United States for U.S. federal estate tax purposes differs from the test used for U.S. federal income tax purposes. Some individuals, therefore,may be non-U.S. holders for U.S. federal income tax purposes, but not for U.S. federal estate tax purposes, and vice versa.

Backup Withholding and Information Reporting

        Generally, we must report annually to the IRS the amount of dividends paid to you, your name and address and the amount of tax withheld, if any.A similar report will besent to you. Pursuant to applicable income tax treaties or other agreements, the IRS may make these reports available to tax authorities in your country of residence.

        Paymentsof dividends or of proceeds on the disposition of stock made to you may be subject to information reporting and backup withholding at a current rate of 24% unless you establishan exemption, for example, by properly certifying your non-U.S. status on an IRS Form W-8BEN, IRS Form W-8BEN-E or another appropriate version of IRS Form W-8.

        Backupwithholding is not an additional tax; rather, the U.S. federal income tax liability of persons subject to backup withholding will be reduced by the amount of tax withheld. Ifwithholding results in an overpayment of taxes, a refund or credit may generally be obtained from the IRS, provided that the required information is furnished to the IRS in a timely manner.

Foreign Account Tax Compliance

        The Foreign Account Tax Compliance Act, or FATCA, imposes withholding tax at a rate of 30% on dividends on and gross proceeds from the sale orother disposition of our common stock paid to "foreign financial institutions" (as specially defined under these rules), unless such institution enters into an agreement with the U.S. government towithhold on certain payments and to collect and provide to the U.S. tax authorities substantial information regarding the U.S. account holders of such institution (which includes certain equity anddebt holders of such

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institution,as well as certain account holders that are foreign entities with U.S. owners) or otherwise establishes an exemption. FATCA also generally imposes a U.S. federal withholding tax of 30% ondividends on and gross proceeds from the sale or other disposition of our common stock paid to a "non-financial foreign entity" (as specially defined for purposes of these rules) unless such entityprovides the withholding agent with a certification identifying certain substantial direct and indirect U.S. owners of the entity, certifies that there are none or otherwise establishes an exemption.The withholding provisions under FATCA generally apply to dividends on ourcommon stock, and under current transition rules, are expected to apply with respect to the gross proceeds from the sale or other disposition of our common stock on or after January 1, 2019. Anintergovernmental agreement between the United States and an applicable foreign country may modify the requirements described in this paragraph. Non-U.S. holders should consult their own tax advisorsregarding the possible implications of this legislation on their investment in our common stock.

        Each prospective investor should consult its own tax advisor regarding the particular U.S. federal, state and local and non-U.S. tax consequences of purchasing,holding and disposing of our common stock, including the consequences of any proposed change in applicable laws.

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UNDERWRITING

Underwriting

        Cantor Fitzgerald & Co. is acting as the sole book running manager of the offering and representative of the underwriters namedbelow. Subject to the terms and conditions stated in the underwriting agreement dated the date of this prospectus, each underwriter named below has severally and not jointly agreed to purchase, and wehave agreed to sell to that underwriter, the number of shares set forth opposite the underwriter's name.

        Theunderwriting agreement provides that the obligations of the underwriters to purchase the shares included in this offering are subject to approval of legal matters by counsel and toother conditions. The underwriters are obligated to purchase all the shares (other than those covered by the over-allotment option described below) if they purchase any of the shares.

        Sharessold by the underwriters to the public will initially be offered at the initial public offering price set forth on the cover of this prospectus. Any shares sold by theunderwriters to securities dealers may be sold at a discount from the initial public offering price not to exceed $            per share. If all the shares are not sold at the initialofferingprice, the underwriters may change the offering price and the other selling terms. The representative has advised us that the underwriters do not intend to make sales to discretionary accounts.

Underwriting discounts and commissions

        The following table shows the underwriting discounts and commissions that we are to pay to the underwriters in connection with this offering.These amounts are shown assuming both no exercise and full exercise of the underwriters' over-allotment option.

Indemnification

        We have agreed to indemnify the underwriters against certain liabilities, including liabilities under the Securities Act, or to contribute topayments the underwriters may be required to make because of any of those liabilities.

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Overallotment Option to Purchase Additional Shares

        If the underwriters sell more shares than the total number set forth in the table above, we have granted to the underwriters an option,exercisable for 30 days from the dateof this prospectus, to purchase up to            additional shares at the public offering price less the underwriting discount. The underwriters may exercise the option solely for thepurpose ofcovering over-allotments, if any, in connection with this offering. To the extent the option is exercised, each underwriter must purchase a number of additional shares approximately proportionate tothat underwriter's initial purchase commitment. Any shares issued or sold under the option will be issued and sold on the same terms and conditions as the other shares that are the subject of thisoffering.

Lock-Ups

        We, our officers and directors, and our other shareholders have agreed that, for a period of 180 days from the date of this prospectus,we and they will not, without the prior written consent of Cantor Fitzgerald & Co., dispose of or hedge any shares or any securities convertible into or exchangeable for our commonstock.

Determination of Offering Price

        Prior to this offering, there has been no public market for our shares. Consequently, the initial public offering price for the shares wasdetermined by negotiations between us and the representative. Among the factors considered in determining the initial public offering price were our results of operations, our current financialcondition, our future prospects, our markets, the economic conditions in and future prospects for the industry in which we compete, our management, and currently prevailing general conditions in theequity securities markets, including current market valuations of publicly traded companies considered comparable to our company. We cannot assure you, however, that the price at which the shares willsell in the public market after this offering will not be lower than the initial public offering price or that an active trading market in our shares will develop and continue after this offering.

The Nasdaq Capital Market Listing

        We have applied to have our shares listed on The Nasdaq Capital Market under the symbol "ARDS."

Expenses and Reimbursements

        We estimate that our portion of the total expenses of this offering will be $            . We have agreed to reimburse theunderwriters up to$            for expenses related to any filing with, and any clearance of this offering by, the Financial Industry Regulatory Authority (FINRA).

Price Stabilization, Short Positions and Penalty Bids

        In connection with the offering, the underwriters may purchase and sell shares in the open market. Purchases and sales in the open market mayinclude short sales, purchases to cover short

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positions,which may include purchases pursuant to the over-allotment option, and stabilizing purchases.

•

Short sales involve secondary market sales by the underwriters of a greater number of shares than they are required to purchase in theoffering.



•

"Covered" short sales are sales of shares in an amount up to the number of shares represented by the underwriters' over-allotmentoption.



•

"Naked" short sales are sales of shares in an amount in excess of the number of shares represented by the underwriters'over-allotment option.



•

Covering transactions involve purchases of shares either pursuant to the underwriters' over-allotment option or in the open market in order tocover short positions.



•

To close a naked short position, the underwriters must purchase shares in the open market. A naked short position is more likelyto be created if the underwriters are concerned that there may be downward pressure on the price of the shares in the open market after pricing that could adversely affect investors who purchase inthe offering.



•

To close a covered short position, the underwriters must purchase shares in the open market or must exercise the over-allotmentoption. In determining the source of shares to close the covered short position, the underwriters will consider, among other things, the price of shares available for purchase in the open market ascompared to the price at which they may purchase shares through the over-allotment option.



•

Stabilizing transactions involve bids to purchase shares so long as the stabilizing bids do not exceed a specified maximum.

        Purchasesto cover short positions and stabilizing purchases, as well as other purchases by the underwriters for their own accounts, may have the effect of preventing or retarding adecline in the market price of the shares. They may also cause the price of the shares to be higher than the price that would otherwise exist in the open market in the absence of these transactions.The underwriters may conduct these transactions on The Nasdaq Capital Market, in the over-the-counter market or otherwise. If the underwriters commence any of these transactions, they may discontinuethem at any time.

Electronic Distribution

        In connection with the offering, certain of the underwriters or securities dealers may distribute prospectuses by electronic means, such ase-mail.

Other Relationships

        The underwriters are full service financial institutions engaged in various activities, which may include securities trading, commercial andinvestment banking, financial advisory, investment management, principal investment, hedging, financing and brokerage activities. The underwriters and their respective affiliates have in the pastperformed commercial banking, investment banking and advisory services for us from time to time for which they have received customary fees and reimbursement of expenses and may, from time to time,engage in transactions with and perform services for us in the ordinary course of their business for which they may receive customary fees

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andreimbursement of expenses. In the ordinary course of their various business activities, the underwriters and their respective affiliates may make or hold a broad array of investments and activelytrade debt and equity securities (or related derivative securities) and financial instruments (which may include bank loans and/or credit default swaps) for their own account and for the accounts oftheir customers and may at any time hold long and short positions in such securities and instruments. Such investments and securities activities may involve securities and/or instruments of ours orour affiliates. The underwriters and their affiliates may also make investment recommendations and/or publish or express independent research views in respect of such securities or financialinstruments and may hold, or recommend to clients that they acquire, long and/or short positions in such securities and instruments.

Sales Outside the United States

        No action has been taken in any jurisdiction (except in the United States) that would permit a public offering of our common stock, or thepossession, circulation or distribution of this prospectus or any other material relating to us or our common stock in any jurisdiction where action for that purpose is required. Accordingly, theshares of common stock may not be offered or sold, directly or indirectly, and neither this prospectus nor any other offering material or advertisements in connection with our common stock may bedistributed or published, in or from any country or jurisdiction, except in compliance with any applicable rules and regulations of any such country or jurisdiction.

        Theunderwriters may arrange to sell the common stock offered hereby in certain jurisdictions outside the United States, either directly or through affiliates, where it is permitted todo so.

European Economic Area

        In relation to each Member State of the European Economic Area which has implemented the Prospectus Directive (each, a "Relevant Member State")an offer to the public of our common shares may not be made in that Relevant Member State, except that an offer to the public in that Relevant Member State of our common shares may be made at any timeunder the following exemptions under the Prospectus Directive:

(a)

toany legal entity which is a qualified investor as defined in the Prospectus Directive;



(b)

tofewer than 150 natural or legal persons (other than qualified investors as defined in the Prospectus Directive), subject to obtaining the prior consent of therepresentative for any such offer; or



(c)

inany other circumstances falling within Article 3(2) of the Prospectus Directive.

        Weprovided that no such offer of shares of our common stock shall result in a requirement for the publication by us or any underwriter of a prospectus pursuant to Article 3 ofthe Prospectus Directive.

        Forthe purposes of this provision, the expression an "offer to the public" in relation to our common shares in any Relevant Member State means the communication in any form and by anymeans of sufficient information on the terms of the offer and our common shares to be offered so as to enable an investor to decide to purchase our common shares, as the same may be varied in thatMember State by any measure implementing the Prospectus Directive in that Member State,

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theexpression "Prospectus Directive" means Directive 2003/71/EC (as amended), including by Directive 2010/73/EU, and includes any relevant implementing measure in the Relevant Member State.

        ThisEuropean Economic Area selling restriction is in addition to any other selling restrictions set out below.

United Kingdom

        In the United Kingdom, this prospectus is only addressed to and directed as qualified investors who are (i) investment professionalsfalling within Article 19(5) of the Financial Services and Markets Act 2000 (Financial Promotion) Order 2005 (the Order); or (ii) high net worth entities and other persons to whom it maylawfully be communicated, falling within Article 49(2)(a) to (d) of the Order (all such persons together being referred to as "relevant persons"). Any investment or investment activityto which this prospectus relates is available only to relevant persons and will only be engaged with relevant persons. Any person who is not a relevant person should not act or relay on thisprospectus or any of its contents.

Hong Kong

        The shares may not be offered or sold in Hong Kong by means of any document other than (i) in circumstances which do not constitute anoffer to the public within the meaning of the Companies (Winding Up and Miscellaneous Provisions) Ordinance (Cap. 32 of the Laws of Hong Kong) ("Companies (Winding Up and Miscellaneous Provisions)Ordinance") or which do not constitute an invitation to the public within the meaning of the Securities and Futures Ordinance (Cap. 571 of the Laws of Hong Kong) ("Securities and Futures Ordinance"),or (ii) to "professional investors" as defined in the Securities and Futures Ordinance and any rules made thereunder, or (iii) in other circumstances which do not result in the documentbeing a"prospectus" as defined in the Companies (Winding Up and Miscellaneous Provisions) Ordinance, and no advertisement, invitation or document relating to the shares may be issued or may be in thepossession of any person for the purpose of issue (in each case whether in Hong Kong or elsewhere), which is directed at, or the contents of which are likely to be accessed or read by, the public inHong Kong (except if permitted to do so under the securities laws of Hong Kong) other than with respect to shares which are or are intended to be disposed of only to persons outside Hong Kong or onlyto "professional investors" in Hong Kong as defined in the Securities and Futures Ordinance and any rules made thereunder.

Singapore

        This prospectus has not been registered as a prospectus with the Monetary Authority of Singapore. Accordingly, this prospectus and any otherdocument or material in connection with the offer or sale, or invitation for subscription or purchase, of the shares may not be circulated or distributed, nor may the shares be offered or sold, or bemade the subject of an invitation for subscription or purchase, whether directly or indirectly, to persons in Singapore other than (i) to an institutional investor (as defined underSection 4A of the Securities and Futures Act, Chapter 289 of Singapore (the "SFA")) under Section 274 of the SFA, (ii) to a relevant person (as defined inSection 275(2) of the SFA) pursuant to Section 275(1) of the SFA, or any person pursuant to Section 275(1A) of the SFA, and in accordance with the conditions specified in

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Section 275of the SFA or (iii) otherwise pursuant to, and in accordance with the conditions of, any other applicable provision of the SFA, in each case subject to conditions set forthin the SFA.

        Wherethe shares are subscribed or purchased under Section 275 of the SFA by a relevant person which is a corporation (which is not an accredited investor (as defined inSection 4A of the SFA)) the sole business of which is to hold investments and the entire share capital of which is owned by one or more individuals, each of whom is an accredited investor, thesecurities (as defined in Section 239(1) of the SFA) of that corporation shall not be transferable for 6 months after that corporation has acquired the shares under Section 275 ofthe SFA except: (1) to an institutional investor under Section 274 of the SFA or to a relevant person (as defined in Section 275(2) of the SFA), (2) where such transferarises from an offer in that corporation's securities pursuant to Section 275(1A) of the SFA, (3) where no consideration is or will be given for the transfer,(4) where the transfer is by operation of law, (5) as specified in Section 276(7) of the SFA, or (6) as specified in Regulation 32 of the Securities and Futures(Offers of Investments) (Shares and Debentures) Regulations 2005 of Singapore ("Regulation 32").

        Wherethe shares are subscribed or purchased under Section 275 of the SFA by a relevant person which is a trust (where the trustee is not an accredited investor (as defined inSection 4A of the SFA)) whose sole purpose is to hold investments and each beneficiary of the trust is an accredited investor, the beneficiaries' rights and interest (howsoever described) inthat trust shall not be transferable for 6 months after that trust has acquired the shares under Section 275 of the SFA except: (1) to an institutional investor underSection 274 of the SFA or to a relevant person (as defined in Section 275(2) of the SFA), (2) where such transfer arises from an offer that is made on terms that such rights orinterest are acquired at a consideration of not less than S$200,000 (or its equivalent in a foreign currency) for each transaction (whether such amount is to be paid for in cash or by exchange ofsecurities or other assets), (3) where no consideration is or will be given for the transfer, (4) where the transfer is by operation of law, (5) as specified inSection 276(7) of the SFA, or (6) as specified in Regulation 32.

Japan

        The securities have not been and will not be registered under the Financial Instruments and Exchange Act of Japan (Act No. 25 of 1948, asamended), or the FIEA. The securities may not be offered or sold, directly or indirectly, in Japan or to or for the benefit of any resident of Japan (including any person resident in Japan or anycorporation or other entity organized under the laws of Japan) or to others for reoffering or resale, directly or indirectly, in Japan or to or for the benefit of any resident of Japan, exceptpursuant to an exemption from the registration requirements of the FIEA and otherwise in compliance with any relevant laws and regulations of Japan.

Canada

        The securities may be sold in Canada only to purchasers purchasing, or deemed to be purchasing, as principal that are accredited investors, asdefined in National Instrument 45-106 Prospectus Exemptions or subsection 73.3(1) of the Securities Act (Ontario), and are permitted clients, as defined in NationalInstrument 31-103 Registration Requirements, Exemptions, and Ongoing Registrant Obligations. Any resale of the securities must be made inaccordance with an exemption form, or in a transaction not subject to, the prospectus requirements of applicable

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securitieslaws. Securities legislation in certain provinces or territories of Canada may provide a purchaser with remedies for rescission or damages if this offering memorandum (including anyamendment thereto) contains a misrepresentation, provided that the remedies for rescission or damages are exercised by the purchaser within the time limit prescribed by the securities legislation ofthe purchaser's province or territory. The purchaser should refer to any applicable provisions of the securities legislation of the purchaser's province or territory of these rights or consult with alegal advisor. Pursuant to section 3A.3 of National Instrument 33-105 Underwriting Conflicts (NI 33-105), the underwriters are not required to comply with the disclosurerequirements of NI 33-105 regarding underwriter conflicts of interest in connection with this offering.

Switzerland

        The shares of common stock may not be publicly offered in Switzerland and will not be listed on the SIX Swiss Exchange, or SIX, or on any otherstock exchange or regulated trading facility in Switzerland. This document has been prepared without regard to the disclosure standards for issuance prospectuses under art. 652a or art. 1156 of theSwiss Code of Obligations or the disclosure standards for listing prospectuses under art. 27 ff. of the SIX Listing Rules or the listing rules of any other stock exchange or regulated trading facilityin Switzerland. Neither this document nor any other offering or marketing material relating to the shares or the offering may be publicly distributed or otherwise made publicly available inSwitzerland. Neither this document nor any other offering or marketing material relating to the offering, us, or the shares have been or will be filed with or approved by any Swiss regulatoryauthority. In particular, this document will not be filed with, and the offer of shares will not be supervised by, the Swiss Financial Market Supervisory Authority FINMA, or FINMA, and the offer ofshares has not been and will not be authorized under the Swiss Federal Act on Collective Investment Schemes, or CISA. The investor protection afforded to acquirers of interests in collectiveinvestment schemes under the CISA does not extend to acquirers of shares.

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LEGAL MATTERS

        The validity of the issuance of the common stock offered by us in this offering will be passed upon for us by Sheppard, Mullin,Richter & Hampton, LLP New York, New York. Certain matters are being passed on for the underwriters by Cooley LLP, San Francisco, California.

EXPERTS

        Mayer Hoffman McCann P.C., our independent registered public accounting firm, has audited our consolidated balance sheets as ofDecember 31, 2017 and 2016, and the related consolidated statements of operations, changes in convertible preferred stock and stockholders' deficit and cash flows for each of the years endedDecember 31, 2017 and 2016, as set forth in their report. We have included our consolidated financial statements in this prospectus and in this registration statement in reliance on the reportof Mayer Hoffman McCann P.C. given on their authority as experts in accounting and auditing.

WHERE YOU CAN FIND MORE INFORMATION

        We have filed with the SEC a registration statement on Form S-1 under the Securities Act with respect to the common stockoffered by this prospectus. This prospectus, which is part of the registration statement, omits certain information, exhibits, schedules and undertakings set forth in the registration statement. Forfurther information pertaining to us and our common stock, reference is made to the registration statement and the exhibits and schedules to the registration statement. Statements contained in thisprospectus as to the contents orprovisions of any documents referred to in this prospectus are not necessarily complete, and in each instance where a copy of the document has been filed as an exhibit to the registration statement,reference is made to the exhibit for a more complete description of the matters involved.

        Youmay read and copy all or any portion of the registration statement without charge at the public reference room of the SEC at 100 F Street, N.E., Washington, D.C. 20549. Copiesof the registration statement may be obtained from the SEC at prescribed rates from the public reference room of the SEC at such address. You may obtain information regarding the operation of thepublic reference room by calling 1-800-SEC-0330. In addition, registration statements and certain other filings made with the SEC electronically are publicly available through the SEC's website at https://www.sec.gov. The registration statement, including all exhibits and amendments to the registration statement, has been filed electronically withthe SEC.

        Uponcompletion of this offering, we will become subject to the information and periodic reporting requirements of the Exchange Act and, accordingly, will be required to file annualreports containing financial statements audited by an independent public accounting firm, quarterly reports containing unaudited financial data, current reports, proxy statements and other informationwith the SEC. You will be able to inspect and copy such periodic reports, proxy statements and other information at the SEC's public reference room, and the website of the SEC referred to above.

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CONSOLIDATED FINANCIAL STATEMENTS

ARIDIS PHARMACEUTICALS, INC.
Index to Consolidated Financial Statements

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REPORT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

Tothe Board of Directors and Stockholders of
Aridis Pharmaceuticals, Inc.

Opinion on the Financial Statements

        We have audited the accompanying consolidated balance sheets of Aridis Pharmaceuticals,Inc. ("Company") as of December 31, 2017 and 2016, and the related consolidated statements of operations, changes in convertible preferred stock and stockholders'deficit, and cash flows for each of the two years in the period ended December 31, 2017, and the related notes (collectively referred to as the "financial statements"). In our opinion, the financialstatements present fairly, in all material respects, the financial position of the Company as of December 31, 2017 and 2016, and the results of its operations and its cash flows for each of the twoyears in the period ended December 31, 2017, in conformity with accounting principles generally accepted in the United States of America.

Basis for Opinion

        These financial statements are the responsibility of the Company's management. Our responsibility is to express an opinion on these financialstatements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) ("PCAOB") and are required to be independent with respectto the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

        Weconducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether thefinancial statements are free of material misstatement, whether due to error or fraud. The Company is not required to have, nor were we engaged to perform, an audit of its internal control overfinancial reporting. As part of our audits we are required to obtain an understanding of internal control over financial reporting but not for the purpose of expressing an opinion on the effectivenessof the Company's internal control over financial reporting. Accordingly, we express no such opinion.

        Ouraudits included performing procedures to assess the risks of material misstatement of the financial statements, whether due to error or fraud, and performing procedures that respondto those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the financial statements. Our audits also included evaluating the accountingprinciples used and significant estimates made by management, as well as evaluating the overall presentation of the financial statements. We believe that our audits provide a reasonable basis for ouropinion.

/s/Mayer Hoffman McCann P.C.

Wehave served as the Company's auditor since 2014.

SanDiego, CA
April 19, 2018

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Aridis Pharmaceuticals, Inc.

Consolidated Balance Sheets

(In thousands, except share and per share amounts)

   

See accompanying notes to the consolidated financial statements.

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Aridis Pharmaceuticals, Inc.

Consolidated Statements of Operations

(In thousands, except share and per share amounts)

   

See accompanying notes to the consolidated financial statements.

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Aridis Pharmaceuticals, Inc.

Consolidated Statements of Changes in Convertible Preferred Stock and Stockholders' Deficit

(In thousands, except share andper share amounts)

   

See accompanying notes to the consolidated financial statements.

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Aridis Pharmaceuticals, Inc.

Consolidated Statements of Cash Flows

(In thousands)

   

See accompanying notes to the consolidated financial statements.

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Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements

(Information as of March 31, 2018 and for the periods ended
March 31, 2018and 2017 are Unaudited)

1. Description of Business and Basis of Presentation

Organization

        Aridis Pharmaceuticals, Inc. (the "Company" or "we" or "our") was established as a California limited liability corporation in 2003. TheCompany converted to a Delaware C corporation on May 21, 2014. Aridis' principal place of business is in San Jose, California. It is a clinical-stage company focused on developing newbreakthrough therapies for infectious diseases and addressing the growing problem of antibiotic resistance. The Company has a deep, diversified portfolio of clinical and pre-clinical stageanti-infective product candidates that are complimented by a fully human monoclonal antibody discovery platform technology. Two of the Company's clinical candidates are at pivotal trial stage. TheCompany's suite of anti-infective monoclonal antibodies offers opportunities to profoundly alter the current trajectory of increasing antibiotic resistance and improve the health outcome of many ofthe most serious life-threatening infections particularly in hospital settings.

Basis of Presentation and Consolidation

        The accompanying consolidated financial statements have been prepared in accordance with the United States generally accepted accountingprinciples, or GAAP. Theconsolidated financial statements include the accounts of the Company and its two wholly-owned subsidiaries, Aridis Biopharmaceuticals, Inc. and Aridis Pharmaceuticals, C.V. All intercompanybalances and transactions have been eliminated in consolidation. The Company operates in one segment. Management uses one measurement of profitability and does not segregate its business for internalreporting.

Liquidity

        The Company has not yet achieved commercialization of its products and has a cumulative net loss from its operations. It will continue to incurnet losses for the foreseeable future. The Company's consolidated financial statements have been prepared assuming that it will continue as a going concern. The Company believes that it has sufficientcash to fund operations for at least twelve months beyond the issuance date of the December 31, 2017 financial statements. The Company will require additional capital to meet its long-term operatingrequirements. It expects to raise additional capital through, among other things, the sale of equity or debt securities. Historically, the Company's principal sources of cash have included proceedsfrom grant funding, fees for services performed and the sale of its preferred stock. The Company's principal uses of cash have included cash used in operations. The Company expects that the principaluses of cash in the future will be for continuing operations, funding of research and development including its clinical trials and general working capital requirements.

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Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

2. Summary of Significant Accounting Policies

Use of Estimates

        The preparation of the consolidated financial statements requires management to make estimates and assumptions that affect the reported amountsof assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of expenses during the reporting period. Suchestimates include those related to the evaluation of our ability to continue as a going concern, revenue recognition, long-lived assets, convertible debt, income taxes, assumptions used in theBlack-Scholes-Merton ("BSM") model to calculate the fair value of stock-based compensation, Monte Carlo Simulation ("MSM") model to calculate the fair value of warrants, deferred tax asset valuationallowances, valuation of the Company's common and convertible preferred stock, fair value assumptions used in the valuation of warrants issued with convertible notes and convertible preferred stockwarrant liabilities, preclinical study and clinical trial accruals and various accrued liabilities. Actual results could differ from those estimates.

Unaudited Interim Consolidated Financial Information

        The consolidated balance sheet as of March 31, 2018 and the consolidated statements of operations and cash flows for the three monthsended March 31, 2018 and 2017 and the consolidated statement of changes in convertible preferred stock and stockholders' deficit for the three months ended March 31, 2018 are unaudited.The unaudited consolidated financial statements have been prepared on a basis consistent with the audited consolidated financial statements and, in the opinion of management, reflect all adjustments(consisting of normal recurring adjustments) considered necessary to fairly state the Company's consolidated financial position as of March 31, 2018 and the results of operations and cash flowsfor the three months ended March 31, 2018 and 2017. The financial data and other information disclosed in the notes to the consolidated financial statements related to March 31, 2018 andthe three months ended March 31, 2018 and 2017 are unaudited.

Concentration of Risk

        The Company's cash and cash equivalents are maintained at financial institutions in the United States of America. Deposits held by theseinstitutions may exceed the amount of insurance provided on such deposits. Most of the Company's customers are located in the United States.

        Forthe year ended December 31, 2017, two customers accounted for 90% and 10% of total revenue. For the year ended December 31, 2016, one customer accounted for approximately 97%of total revenue. As of December 31, 2017, there was no accounts receivable and as of December 31, 2016, one customer accounted for 100% of accounts receivable. For the three months ended

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Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

2. Summary of Significant Accounting Policies (Continued)

March 31,2018 and 2017, one customer accounted for 100% of total revenue. As of March 31, 2018, one customer accounted for 100% of accounts receivable.

Cash and Cash Equivalents

        The Company considers all highly liquid investments purchased with an original maturity of three months or less to be cash equivalents. Cashequivalents consist primarily of checking account and money market account balances.

Accounts Receivable and Allowance for Doubtful Accounts

        Accounts receivable are recorded at the invoiced amount and do not bear interest. The Company considers the credit worthiness of its customers,but does not require collateral in advance of a sale. The Company evaluates collectability and maintains an allowance for doubtful accounts for estimated losses inherent in its accounts receivableportfolio when necessary. The allowance is based on the Company's best estimate of the amount of losses in the Company's existing accounts receivable, which is based on customer creditworthiness,facts and circumstances specific to outstanding balances, and payment terms. Account balances are charged off against the allowance after all means of collection have been exhausted and the potentialfor recovery is considered remote. As of December 31, 2017 and 2016, and March 31, 2018, there were no allowances for doubtful accounts.

Property and Equipment

        Property and equipment are stated at cost less accumulated depreciation. Depreciation is computed using the straight-line method over theestimated useful lives of the assets, generally between three and five years. Maintenance and repairs are charged to expense as incurred. When assets are retired or otherwise disposed of, the cost andaccumulated depreciation are removed from the balance sheet and any resulting gain or loss is reflected in the consolidated statement of operations and comprehensive loss in the period realized.

Intangible Assets

        Intangible assets are recorded at cost and amortized over the estimated useful life of the asset. Intangible assets consist of licenses withvarious institutions whereby the Company has rights to use intangible property obtained from such institutions.

Impairment of Long-Lived Assets

        The Company reviews long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of an assetmay not be recoverable. Recoverability

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Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

2. Summary of Significant Accounting Policies (Continued)

ismeasured by comparison of the carrying amount to the future net cash flows which the assets are expected to generate. If such assets are considered to be impaired, the impairment ismeasured by the excess of the carrying amount of the assets over fair value less the costs to sell the assets, generally determined using the projected discounted future net cash flows arising fromthe asset. There have been no such impairments of long-lived assets as of December 31, 2017 and 2016 and March 31, 2018.

Revenue Recognition

        Revenue is recognized in accordance with the Financial Accounting Standards Board ("FASB") Accounting Standards Codification ("ASC") 605,Revenue Recognition which requires that four basic criteria must be met before revenue can be recognized: (1) persuasive evidence of an arrangement exists; (2) delivery has occurred andtitle and the risks and rewards of ownership have been transferred to the client or services have been rendered; (3) the price is fixed or determinable; and (4) collectability isreasonably assured.

        During2017 and 2016, revenue includes grant awards and contract services entered into with government and other agencies for specific research and development efforts. We recognizerevenue under such awards and contracts as the related qualified research and development expenses are incurred or under the milestone method, up to the limit of the prior approval funding amounts,and when we have determined that we have earned the right to receive the recognized portion according to the terms of the original grant awarded.

        During2016, all grant revenue was derived from a grant awarded by the National Institute of Health. All contract revenue was derived from a contract with the National Institute ofHealth and small amounts of fee-for-service contracts with other third parties. The Company recorded approximately $1,072,000 during the year ended 2016 for its contract with the National Institute ofHealth. The contract ended during late 2016.

        InDecember 2016, the Company received an award from the Cystic Fibrosis Foundation ("CF Foundation") for approximately $2,902,000. The agreement contains an upfront payment of $200,000which is being recognized straight-line over the term of the contract as we believe the upfront fee relates to services performed throughout the contract period and the upfront fee does not representa substantive milestone within the agreement. Recognition of revenue for the remaining payments under the agreement will be recognized under the milestone method as substantive milestones are met. Themilestones relate to pre-clinical research activities. The agreement also specifies that we are obligated to cumulatively spend on the development program at least an equal amount as it receives fromthe non-profit organization. In the event that we donot spend as much as we received under the agreement, we are obligated to return any overage to the non-profit organization.

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Table of Contents

Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

2. Summary of Significant Accounting Policies (Continued)

        Forthe year ended December 31, 2017, all grant revenue totaling approximately $89,000 was derived from our award agreement with the CF Foundation. For the three months endedMarch 31, 2018, all grant revenue totaling approximately $322,000 was derived from our award agreement with the CF Foundation.

        In2017, the Company entered into a collaborative research and development agreement with GlaxoSmithKline plc ("GSK"). In accordance with the agreement, we received an upfront fee andare due annual fees and amounts for development work to be performed as specifically outlined under the agreement. The work to be performed was delineated into three specific research projects. Inassessing the appropriate revenue recognition related to a collaboration agreement, we first determined whether the arrangement includes multiple elements, such as the delivery of intellectualproperty rights and research and development services. The multiple elements were analyzed to determine whether the deliverables could be separated or whether they must be accounted for as a singleunit of accounting. Amounts received prior to satisfying the revenue recognition criteria are recorded as deferred revenue in our balance sheet. Recognition of revenue under the contract will be basedon the terms of the contract and will be recognized under the proportional performance method derived from the completion of certain stages as defined within the contract.

        Forthe year ended December 31, 2017, approximately $771,000 was recorded as collaboration revenue related to the Company's agreement with GSK. For the three months endedMarch 31, 2018, no collaboration revenue was recorded under the Company's agreement with GSK.

Cost of Contract Revenue

        Cost of contract revenue includes the expenses incurred to perform contracted services for third parties which exclude grant related activities.The costs include employee salaries, lab supplies, outsourced activities associated and allocated facilities and employee benefit expenses.

Costs for Collaborative Arrangements

        Costs incurred under collaborative arrangements include personnel costs, laboratory supplies and fees paid to third parties. These amounts areincluded in research and development in the accompanying consolidated statement of operations. For the year ended December 31, 2017 and 2016, the Company had incurred expenses of approximately$633,000 and $0, respectively, related to its collaborative arrangement. For the three months ended March 31, 2018 and 2017, the company had incurred expenses of approximately $157,000 and$136,000, respectively, related to its collaborative arrangement.

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Table of Contents

Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

2. Summary of Significant Accounting Policies (Continued)

Research and Development

        Research and development costs are charged to operations as incurred. Research and development expenses consist of salaries and benefits,laboratory supplies, consulting fees and fees paid to third parties.

Stock-Based Compensation

        The Company recognizes compensation expense for all stock-based awards to employees and directors based on the grant-date estimated fair values,net of an estimated forfeiture rate. The Company recognizes stock-based compensation cost for employees and directors on a straight-line basis over the requisite service period for the award.Stock-based compensation expense is recognized only for those awards that are ultimately expected to vest. The Company estimates forfeitures based on an analysis of historical employee turnover andwill continue to evaluate the appropriateness of the forfeiture rate based on actual forfeiture experience, analysis of employee turnover and other factors. The Company will revise the forfeitureestimate, if necessary, in subsequent periods if actual forfeitures differ from those estimates. Changes in forfeiture estimates impact stock-based compensation cost in the period in which the changein estimate occurs.

        TheBSM option pricing model incorporates various highly sensitive assumptions, including the fair value of the Company's common stock, expected volatility, expected term and risk-freeinterest rates. The weighted-average expected life of options was calculated using the simplified method as prescribed by the SEC's Staff Accounting Bulletin No. 107 ("SAB No. 107").This decision was based on the lack of relevant historical data due to the Company's limited historical experience. In addition, due to the Company's limited historical data, the estimated volatilityalso reflects the application of SAB No. 107, incorporating the historical volatility of comparable companies whose stock prices are publicly available. The risk-free interest rate for theperiods within the expected term of the option is based on the U.S. Treasury yield in effect at the time of grant. The dividend yield was zero, as the Company has never declared or paid dividends andhas no plans to do so in the foreseeable future.

        TheCompany accounts for stock-based compensation arrangements with non-employees by recording the expense of such services based on the estimated fair value of the common stock at themeasurement date. The value of the equity instrument, including adjustment to fair value at each balance sheet date, is charged to net loss over the term of the service agreement.

        Dueto the absence of a public market trading for the Company's common stock, it is necessary to estimate the fair value of the common stock underlying the Company's stock-based awardswhen performing fair value calculations. The estimated fair value of the Company's common stock was determined using methodologies, approaches and assumptions consistent with

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Table of Contents

Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

2. Summary of Significant Accounting Policies (Continued)

theAmerican Institute of Certified Public Accountants, or AICPA, Practice Aid: Valuation of Privately-Held-Company Equity Securities Issued as Compensation.

Income Taxes

        The Company accounts for income taxes under the liability method. Under this method, deferred tax assets and liabilities are determined based onthe difference between the financial statement and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to affect taxable income.Valuation allowances are established when necessary to reduce deferred tax assets to the amounts expected to be realized.

        TheCompany assesses all material positions taken in any income tax return, including all significant uncertain positions, in all tax years that are still subject to assessment orchallenge by the relevant taxing authorities. Assessing an uncertain tax position begins with the initial determination of the positions sustainability and is measured at the largest amount of benefitthat is greater than fifty percent likely of being realized upon ultimate settlement. At each balance sheet date, unresolved uncertain tax positions must be reassessed, and the Company will determinewhether (i) the factors underlying the sustainability assertion have changed and (ii) the amount of the recognized benefit is still appropriate. The recognition and measurement of taxbenefits requires significant judgment. Judgments concerning the recognition and measurement of a tax benefit might change as new information becomes available.

Comprehensive Loss

        The Company has no items of comprehensive income or loss other than net loss.

Loss Per Share

        Basic loss per common share is calculated by dividing net loss available to common shareholders for the period by the weighted-average number ofcommon shares outstanding during the period. For diluted loss per share calculation purposes, the net loss available to commons shareholders is adjusted to add back any preferred stock dividends andany interest on convertible debt reflected in the consolidated statement of operations for the respective periods.

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Table of Contents

Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

2. Summary of Significant Accounting Policies (Continued)

        Thefollowing potentially dilutive securities were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented becauseincluding them would have been antidilutive:

        Allof the Company's outstanding preferred stock warrants contain a provision such that if the Company has not yet consummated a firm commitment underwritten initial public offering byAugust 12, 2019, the number of warrants will increase by 100%.

JOBS Act Accounting Election

        The JOBS Act permits an "emerging growth company" such as us to take advantage of an extended transition period to comply with new or revisedaccounting standards applicable to public companies. We are choosing to take advantage of this provision and, as a result, we will adopt the extended transition period available under the JOBS Actuntil the earlier of the date we (i) are no longer an emerging growth company or (ii) affirmatively and irrevocably opt out of the extended transition period provided under the JOBS Act.

Recent Accounting Pronouncements

        In July 2017, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2017-11, Earnings PerShare (Topic 260); Distinguishing Liabilities from Equity (Topic 480); Derivatives and Hedging (Topic 815): (Part I) Accounting for Certain Financial Instruments with Down Round Features;(Part II) Replacement of the Indefinite Deferral for Mandatorily Redeemable Financial Instruments of Certain Nonpublic Entities and Certain Mandatorily Redeemable Noncontrolling Interests witha Scope Exception ("ASU 2017-11"). ASU 2017-11 allows companies to exclude a down round feature when determining whether a financial instrument (or embedded conversion feature) is consideredindexed to the entity's own stock. As a result, financial instruments (or embedded conversion features) with down round features may no longer be required to be accounted for as derivative

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Table of Contents

Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

2. Summary of Significant Accounting Policies (Continued)

liabilities.A company will recognize the value of a down round feature only when it is triggered and the strike price has been adjusted downward. For equity-classified freestanding financialinstruments, an entity will treat the value of the effect of the down round as a dividend and a reduction of income available to common shareholders in computing basic earnings per share. Forconvertible instruments with embedded conversion features containing down round provisions, entities will recognize the value of the down round as a beneficial conversion discount to be amortized toearnings. ASU 2017-11 is effective for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years. Early adoption is permitted. The guidance in ASU 2017-11can be applied using a full or modified retrospective approach. The Company is currently evaluating the impact of adopting this guidance.

        InMay 2017, the FASB issued ASU 2017-09, "Compensation — Stock Compensation (Topic 718): Scope of Modification Accounting," to provide clarity and reduce bothdiversity in practice and cost complexity when applying the guidance in Topic 718 to a change to the terms and conditions of a stock-based payment award. ASU 2017-09 also provides guidanceabout the types of changes to the terms or conditions of a share-based payment award that require an entity to apply modification accounting in accordance with Topic 718. For all entities, includingemerging growth companies, the standard is effective for annual periods beginning after December 15, 2017, and for interim periods therein. Early adoption is permitted. The adoption of thisstandard did not have a material effect.

        InJanuary 2017, the FASB issued ASU No. 2017-04, "Intangibles—Goodwill and Other: Simplifying the Test for Goodwill Impairment," to simplify the subsequentmeasurement of goodwill by eliminating Step 2 from the goodwill impairment test. The standard is effective for public entities for annual or any interim goodwill impairment tests in annual reportingperiods beginning after December 15, 2019. For all other entities, including emerging growth companies, the standard is effective for annual or any interim goodwill impairment tests in annualreporting periods beginning after December 15, 2021. Early adoption of this standard is permitted. The Company is currently evaluating the impact of adopting this guidance.

        InAugust 2016, the FASB issued ASU 2016-15, "Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments." ASU 2016-15 reduces diversity in practiceby providing guidance on the classification of certain cash receipts and payments in the statement of cash flows. ASU 2016-15 clarifies that when cash receipts and cash payments have aspects of morethan one class of cash flows and cannot be separated, classification will depend on the predominant source or use. ASU 2016-15 is effective on a retrospective basis for fiscal years, and for interimperiods within those fiscal years, beginning after December 15, 2018, with early adoption permitted. The Company is currently evaluating the impact of adopting this guidance.

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Table of Contents

Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

2. Summary of Significant Accounting Policies (Continued)

        InApril 2016, the FASB issued ASU No. 2016-10, "Revenue from Contract with Customers: Identifying Performance Obligations and Licensing." The amendments in this Update clarifythe two following aspects (a) contracts with customers to transfer goods and services in exchange for consideration and (b) determining whether an entity's promise to grant a licenseprovides a customer with either a right to use the entity's intellectual property (which is satisfied at a point in time) or a right to access the entity's intellectual property (which is satisfiedover time). The amendments in this Update are intended to reduce the degree of judgment necessary to comply with Topic 606. The new standard is effective for fiscal years beginning afterDecember 15, 2018. The Company is currently evaluating the impact of adopting this guidance.

        InMarch 2016, the FASB issued ASU No. 2016-09, "Improvements to Employee Share-Based Payment Accounting," which is intended to improve the accounting for employee share-basedpayments. The ASU simplifies several aspects of the accounting for share-based payment award transactions, including; the income tax consequences, classification of awards as either equity orliabilities, and the classification on the statement of cash flows. The new standard is effective for fiscal years beginning after December 15, 2017, and upon adoption, an entity should applythe amendments by means of a cumulative-effect adjustment to the balance sheet at the beginning of the first reporting period in which the guidance is effective. Early adoption is permitted. Theadoption of this standard did not have a material effect.

        InFebruary 2016, the FASB issued ASU No. 2016-02, "Leases (Topic 842)." The pronouncement requires the recognition of a liability for lease obligations and a correspondingright-of-use asset on the balance sheet and disclosure of key information about leasing arrangements. This pronouncement is effective for reporting periods beginning after December 15, 2019using a modified retrospective adoption method. The Company is currently evaluating the impact of adopting this guidance.

        InMay 2014, the FASB issued ASU No. 2014-19, "Revenue from Contracts with Customers." The objective of ASU 2014-19 is to establish a single comprehensive model for entities touse in accounting for revenue arising from contracts with customers and will supersede most of the existing revenue recognition guidance, including industry-specific guidance. The core principle ofASU 2014-09 is that an entity recognizes revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to beentitled in exchange for those goods or services. The new guidance is effective for annualreporting periods (including interim periods within those periods) beginning after December 15, 2018. Early adoption is not permitted. The standard permits the use of either a retrospective ormodified retrospective (cumulative effect) transition method. The Company is currently evaluating the impact of adopting this guidance.

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Table of Contents

Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

3. Fair Value Disclosure

        The carrying value of the Company's cash and cash equivalents, prepaid expenses and other current assets, other assets, accounts payable, accrued liabilities, and convertible notespayable approximate fair value due to the short-term nature of these items.

        Fairvalue is defined as the exchange price that would be received for an asset or an exit price paid to transfer a liability in the principal or most advantageous market for the assetor liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize theuse of unobservable inputs.

        Thefair value hierarchy defines a three-level valuation hierarchy for disclosure of fair value measurements as follows:

        Thecategorization of a financial instrument within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement.

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Table of Contents

Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

3. Fair Value Disclosure (Continued)

 

        Financialassets or liabilities are considered Level 3 when their fair values are determined using pricing models, discounted cash flow methodologies or similar techniques and atleast one significant model assumption or input is unobservable. The preferred stock warrants are measured using the Monte Carlo valuation model which is based, in part, upon inputs for which there islittle or no observable market data, requiring the Company to develop its own assumptions. The assumptions used in calculating the estimated fair value of the warrants represent the Company's bestestimates; however, these estimates involve inherent uncertainties and the application ofmanagement judgment. As a result, if factors change and different assumptions are used, the warrant liability and the change in estimated fair value of the warrants could be materially different.

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Table of Contents

Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

4. Balance Sheet Components

Property and Equipment, net

        Property and equipment, net consist of the following as of December 31, 2017 and 2016 and March 31, 2018 (in thousands):

        Depreciationexpense was approximately $57,000 and $18,000 the year ended December 31, 2017 and 2016, respectively. Depreciation expense was approximately $50,000 and $4,000 forthe three months ended March 31, 2018 and 2017, respectively.

Intangible Assets, net

        Intangible assets, net consist of the following (in thousands) as of December 31, 2017 and 2016 and March 31, 2018:

        Amortizationexpense was approximately $5,000 and $5,000 for the year ended December 31, 2017 and 2016, respectively. Amortization expense was approximately $1,000 and $1,000 forthe three months ended March 31, 2018 and 2017, respectively.

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Table of Contents

Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

4. Balance Sheet Components (Continued)

        Theestimated acquired intangible amortization expense for the next five fiscal years is as follows (in thousands):

Licenses

University Licensing Agreements

The University of Chicago — Co-Exclusive Patent License Agreement

        We are party to a co-exclusive licensing agreement with The University of Chicago (UOC), a non-profit university. This agreement granted to us aco-exclusive, royalty-bearing license for staph alpha toxin technology. The UOC agreement also granted to us the right to sublicense. UOC retained the non-transferrable right to use such patent rightsfor academic and research purposes, and also to certain pre-existing rights of the U.S. government. We paid an upfront fee upon the execution of the agreement and are obligated to pay an annualmaintenance fee. We also are obligated to pay UOC low single digit percentage royalties on net sales from our and our sublicensee's sale of any commercialized licensed product or process, and certainother payments, subject to a minimum amount. We are responsible for our pro rata share of patent expenses.

        Theagreement provides that we have certain obligations to conduct further research and development, and are obligated to utilize reasonable efforts to commercialize, either directly orthrough a sublicensee, the licensed UOC patent rights as licensed products or processes.

        Theterm of the agreement continues until all patents and filed patent applications, included within the licensed UOC patents, have expired or been abandoned, or until the agreement isearlier terminated. We may terminate the agreement on prior written notice to UOC. Each party has the right to terminate the agreement for the other party's uncured material breach of obligationsunder the agreement.

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Table of Contents

Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

4. Balance Sheet Components (Continued)

The Brigham and Women's Hospital, Inc. — Exclusive Patent License Agreement

        We are party to an exclusive licensing agreement with The Brigham and Women's Hospital, Inc. (BWH), a non-profit corporation. Thisagreement granted to us an exclusive, royalty-bearing license under its and Beth Israel Deaconess Medical Center's (BIDMC) rights in methods and composition relating to specific binding peptides to P.aeruginosa mucoid exopolysaccharide to make, use and sell products and processes for the treatment of pseudomonas infections in humans that arecovered by such patent rights. The BWH agreement also granted to us the right to sublicense. BWH and BIDMC retained the non-transferrable right to use such patent rights for academic and researchpurposes, and also to certain pre-existing rights of the U.S. government. We also are obligated to pay BWH low single digit percentage royalties on net sales from our and our sublicensee's sale of anycommercialized licensed product or process, and certain other payments. We are responsible for diligently prosecuting and maintaining the licensed patent rights, at our sole cost and expense.

        Theagreement provides that we have certain obligations to conduct further research and development, and are obligated to utilize reasonable efforts to commercialize, either directly orthrough a sublicensee, the licensed BWH patent rights as licensed products or processes.

        Theterm of the agreement continues until all patents and filed patent applications, included within the licensed BWH patents, have expired or been abandoned, or until the agreement isearlier terminated. We may terminate the agreement on prior written notice to BWH. Each partyhas the right to terminate the agreement for the other party's uncured material breach of obligations under the agreement.

The University of Iowa Research Foundation — Exclusive Patent License Agreement

        We are party to an exclusive licensing agreement with The University of Iowa Research Foundation (UIRF). The UIRF agreement granted to us anexclusive, royalty-bearing license under its rights in methods relating to gallium containing compounds for the treatment of infections to make, use and sell products that are covered by such patentrights. The UIRF agreement also granted to us the right to sublicense. UIRF retained the right and ability to grant right to use such patent rights for academic and research purposes, and also tocertain pre-existing rights of the U.S. government including the United States Department of Veterans Affairs. We also are obligated to pay UIRF low single digit percentage royalties on net sales fromour and our sublicensee's sale of any commercialized licensed product or process, and certain other payments. We are responsible for diligently prosecuting and maintaining the licensed UIRF patentrights, at our sole cost and expense.

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Table of Contents

Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

4. Balance Sheet Components (Continued)

        Theagreement provides that we have certain obligations to conduct further research and development, and are obligated to utilize reasonable efforts to commercialize, either directly orthrough a sublicensee, the licensed UIRF patent rights as licensed products or processes.

        Theterm of the agreement continues until the expiration of the last to expire patents, included within the licensed UIRF patents, or until the agreement is earlier terminated. We mayterminate the agreement on prior written notice to UIRF. Each party has the right to terminate the agreement for the other party's uncured material breach of obligations under the agreement.

Brigham Young University — Exclusive Patent License Agreement

        We are party to an exclusive licensing agreement with Brigham Young University (BYU). This agreement granted to us an exclusive, royalty-bearinglicense under its rights in stabilization of biological agents methods relating to human vaccines to make, use and sell products that are covered by such patent rights. The agreement also granted tous the right to sublicense. BYU and the Church of Jesus Christ of Latter-day Saints and the Church Education System retained the right and ability to use such patent rights for academic andecclesiastical purposes and also to purchase products using such patents rights at a discounted price. We also are obligated to pay BYU low single digit percentage royalties on net sales from our andour sublicensee's sale of any commercialized licensed product, and certain other payments. BYU is responsible for diligently prosecuting and maintaining the licensed BYU patent rights and we reimbursethem for one-third of their costs.

        Theagreement provides that we have certain obligations to conduct further research and development, and are obligated to utilize reasonable efforts to commercialize, either directly orthrough a sublicensee, the licensed BYU patent rights as licensed products or processes.

        Theterm of this agreement continues until the expiration of the last to expire patents, included within the licensed BYU patents, or until the agreement is earlier terminated. We mayterminate the agreement on prior written notice to BYU. Each party has the right to terminate the agreement for the other party's uncured material breach of obligations under the agreement.

Public Health Service Licensing Agreement

NIH ("National Institutes of Health") — Exclusive and Non-Exclusive Patent LicenseAgreement

        We are party to an exclusive and non-exclusive licensing agreement with the NIH. This agreement granted to us an exclusive, royalty-bearinglicense in our exclusive territory and non-exclusive rights in the non-exclusive territory under its rights in a human rotavirus vaccine based on their human-bovine rotavirus reassortants to make, useand sell products and processes that are covered by such patent rights. The agreement also granted to us the right to sublicense.

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Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

4. Balance Sheet Components (Continued)

        Ourlicense under this agreement is subject to the U.S. government's retained rights under a non-exclusive, worldwide, royalty-free license for the practice of all inventions licensedunder the Public Health Service, or PHS, patent rights, by or on behalf of the U.S. government and on behalf of any foreign government or international organization pursuant to any existing or futuretreaty or agreement to which the U.S. government is a signatory. For purposes of encouraging basic research, the U.S. government also reserves the right to grant or require us to grant to a thirdparty on reasonable terms a non-exclusive, non-transferable license to make and use the licensed products or licensed processes for research purpose only, but subject to PHS consulting with us in theevent such third party is a commercial entity. Under certain exceptional and enumerated circumstances, the U.S. government may require us to grant a sublicense to a responsible third party applicant,on terms that are reasonable under the circumstances. The PHS takes responsibility for all aspects of the preparation, filing, prosecution and maintenance of any and all patent applications or patentsincluded in the licensed PHS patent rights, subject to our payment of certain patent-related expenses.

        Wealso are obligated to pay PHS low single digit percentage royalties on net sales from our and our sublicensee's sale of any commercialized licensed product or process, and certainother payments. PHS is responsible for diligently prosecuting and maintaining the licensed PHS patent rights, and we reimburse them for a portion of their costs.

        Theagreement provides that we have certain obligations to conduct further research and development, and are obligated to utilize reasonable efforts to commercialize, either directly orthrough a sublicensee, the licensed PHS patent rights as licensed products or processes.

        Theterm of the PHS agreement continues until the expiration of all royalty obligations, included within the licensed PHS patents, or until the agreement is earlier terminated. We mayterminate the agreement on prior written notice to PHS. Each party has the right to terminate the agreement for the other party's uncured material breach of obligations under the agreement.

Non-Profit Licensing Agreements

Program for Appropriate Technology in Health and PATH Vaccine Solutions

        We granted the Program for Appropriate Technology in Health (PATH), a global non-profit organization, and the PATH Vaccine Solutions anon-exclusive license, with right to sublicense formulations, for use with the measles, rotavirus, live-attenuated influenza, pneumococcal and enteric vaccines only for sale in developing countries.

        Wehave also agreed to provide rotavirus vaccines to public sector purchasers in developing countries at a preferential price relative to private sector purchasers in developingcountries where the rotavirus vaccine utilizing the enabling formulation technology is offered for sale.

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Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

4. Balance Sheet Components (Continued)

Corporate Licensing Agreements

Kenta Biotech Ltd.

        We are party to an asset purchase agreement with Kenta Biotech Ltd. (Kenta), a for profit corporation (Aktiengesellschaft) dulyincorporated in Schlieren (Canton of Zurich, Switzerland), registered under the identification number CH-035.3.035.876-2. The agreement assigned and transferred certain of Kenta's physicalassets, contracts and technology to us. The physical assets included all physical assets owned or controlled by Kenta, including but not limited to cell lines, genes, antibodies, diagnostic assays andrelated documentation, which were related to Kenta's MabIgX technology platform for hybridoma generation and its mAb targeting S. aureus, P. aeruginosa, A. baumannii and RSV. The technology included all intellectual property, includingbut not limited to patents, patent applications, trademarks, knowhow, trade secrets, regulatory filings, clinical trials, clinical trial information, all supporting documentation and all other relatedintellectual property which are related to Kenta's MabIgX technology platform for hybridoma generation and its mAb targeting S. aureus, P. aeruginosa,A. baumannii and RSV. The contracts included the contracts and agreements (including allrights and obligations thereunder), whether oral or written, which Kenta has concluded and which pertain to the assets. The contracts were primarily related to the ongoing clinical trial of AR 301.

        Wewere obligated to pay Kenta a fixed purchase price, which was fully paid during 2013 and 2014, and a declining scale of low double digit to low single digit percentage royalties ongross licensing revenues from either out licensing of the assets or net sales revenues actually received by us up to a maximum of $50,000,000.

        Asof March 31, 2018, no milestones or royalty obligations had been met on these license agreements.

Emergent Product Development Gaithersburg Inc.

        We are party to a license agreement with Emergent Product Development Gaithersburg Inc. (Emergent). We granted Emergent an exclusive,perpetual, royalty-bearing license to use certain of our patents and related know how for the prevention or treatment of infection or illness caused by biodefense pathogens. We also granted anon-exclusive, royalty-bearing license to use certain of our patents and related know how for the prevention or treatment of tularemia and viral hemorrhagic fever indications.

        Emergentis obligated to pay us low single digit percentage royalties on net sales from their and their sublicensee's sale of any commercialized licensed product, and certain otherpayments. The Company has certain diligence obligations to conduct further research and development, and to exploit licensed products.

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Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

4. Balance Sheet Components (Continued)

Accrued Liabilities

        Accrued liabilities consist of the following at December 31, 2017 and 2016 and March 31, 2018 (in thousands):

5. Borrowings

Line of Credit

        In July 2013, the Company entered into a line of credit with Bank of the West whereby the Company can borrow up to $300,000. Under the terms ofthe line of credit, the Company was required to make interest payments on a monthly basis during any period in which any principal remains outstanding on the loan. The line of credit bears a variableinterest rate based on changes in the index of the financial institution's prime rate. The line of credit was guaranteed and collateralized by the Company's assets, and the assets of its twoco-founding members. As of December 31, 2015, there was $300,000, outstanding on this line of credit bearing interest at 3.25%. In July 2016, the $300,000 was paid off in full and the line ofcredit was terminated.

December 2015 Convertible Notes

        In December 2015, the Company issued $3.75 million in convertible notes ("December 2015 convertible notes") with detachable warrants (seenote 6) to various investors. The notes bear no interest, unless the loan is in default in which case a 12% interest rate applies,and carry a maturity date of one year from issuance. Under the terms of the notes, in the event the automatic conversion features are not triggered, all of the principal owed is to convert into sharesof the Company's Series A convertible preferred stock upon the maturity date. The conversion price is equal to the quotient obtained by dividing (a) the principal amount of the notesplus accrued and unpaid interest thereon through the maturity date by (b) a conversion price equal to the quotient obtained by dividing $60.0 million by the aggregate number ofoutstanding shares of the

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Table of Contents

Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

5. Borrowings (Continued)

Company'spreferred stock, as if converted into common stock, and common stock on the maturity date.

        Thenotes contain automatic conversion features whereupon the closing of an initial public offering of the Company's securities (an "IPO") consummated on or prior to the maturity dateand without any action on the part of the note holder, the entire outstanding principal amount of and any accrued and unpaid interest would automatically convert into a number of shares of commonstock equal to the quotient obtained by dividing (i) the outstanding principal amount of the notes plus the accrued and unpaid interest thereon, by (ii) a conversion price equal toseventy (70%) percent of the price at which the Company's common stock is first offered to the public.

        TheDecember 2015 convertible notes were originally recorded at a carrying amount of $3.36 million, net of discount for common stock warrants of approximately $386,000 (seenote 6), with an effective interest rate of approximately 11.5%.

        OnDecember 15, 2016, the December 2015 convertible notes matured. Upon maturity, 1,594,361 shares of Series A convertible preferred stock were issued to all holders of theDecember 2015 convertible notes at a conversion price of $2.35 per share.

6. Warrants to Purchase Common Stock

        In November 2015, an engagement letter was effectuated with the Company's current Vice Chairman of the Board of Directors. Under the terms of the engagement, upon being appointedthe Company's Vice Chairman and the closing of a minimum of $25 million in gross proceeds from sales of its Series A convertible preferred stock under a private placement memorandum, theVice Chairman would receive 1,507,305 common stock warrants. On December 12, 2016, both of the aforementioned conditions had been met and the Company issued 1,507,305 common stock warrants atan exercise price of $2.26 per share.

        Thefair value of the warrants was determined using a Monte Carlo simulation method which calculates the estimated value based on running numerous simulations and analyzing the variousoutcomes. The total fair value of award was approximately $661,000 and will be amortized over the five-year vesting period. For the year ended December 31, 2017 and 2016, the Company recordedstock-based compensation expense of approximately $132,000 and $7,000, respectively, related to these warrants. For the three months ended March 31, 2018 and 2017, the Company recordedstock-based compensation expense of approximately $34,000 and $34,000, respectively, related to these warrants.

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Table of Contents

Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

6. Warrants to Purchase Common Stock (Continued)

        In December 2015, in connection with the December 2015 convertible notes, the Company issued warrants to purchase shares of common stock in the aggregate value of $3.75 million ata price and quantity that is dependent on future events. If, prior to the first anniversary date of the warrants, an IPO is consummated the exercise price will be the issuance price first offered inthe IPO. If an IPO is not consummated prior to the first anniversary the exercise price will be determined by dividing (a) $60.0 million, by (b) the aggregate number ofoutstanding shares of common stock on the first anniversary (assuming the full conversion, exercise or exchange of all securities outstanding on the first anniversary convertible into, exercisable orexchangeable for, shares of common stock). Upon the conversion of the December 2015 convertible notes on December 15, 2016, the exercise price of the warrants was set at approximately $2.35 pershare. The number of shares issuable upon exercise of the warrants was 1,594,361.

        Thefair value of the warrants was determined using a Monte Carlo simulation method which calculates the estimated value based on running numerous simulations and analyzing the variousoutcomes. Upon the issuance of the warrants, the Company recorded additional paid-in capital and a discount to the December 2015 convertible notes, of approximately $386,000. The discount is amortizedto interest expense over the term of the notes. Amortization expense was approximately $369,000 year ended December 31, 2016.

7. Convertible Preferred Stock and Preferred Stock Warrants

        On August 12, 2016, the Company had 10,364,429 outstanding shares of its Series A convertible preferred stock and reduced the stated value of its Series Aconvertible preferred stock from $2.50 per share to $2.05 per share. Due to this change, the Company reduced the amount of its Series A convertible preferred stock carrying value by$4.7 million and moved it to the Company's additional paid-in capital account.

        Eachshare of Series A convertible preferred stock is entitled to voting rights equivalent to the number of shares of common stock into which each share can be converted. Each ofSeries A convertible preferred stock is convertible at the holders' option at any time into common stock on a one for one basis. Upon the liquidation, dissolution or winding up of the businessof the Company, whether voluntary or involuntary, each holder of Series A convertible preferred stock shall be entitled to receive, for each share thereof, out of assets of the Company legallyavailable therefore, a preferential amount in cash equal to (and not more than) $2.05 per share. If upon any such distribution the assets of the Company shall be insufficient to pay the holders of theoutstanding shares of Series A convertible preferred stock the full amounts to which they shall be entitled, such holders shall share ratably in any distribution of assets in accordance withthe sums which would be payable on such distribution if all sums payable thereon were paid in full. Any remaining assets or funds of the Company available for distribution to stockholders shall be

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Table of Contents

Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

7. Convertible Preferred Stock and Preferred Stock Warrants (Continued)

distributedamong the holders of Series A convertible preferred stock and common stock pro rata based on the number of shares of common stock held by each (assuming conversion of all suchSeries A convertible preferred stock and convertible common stock, if any, according to their respective terms). Conversion of Series A convertible preferred stock is automatic upon thecompletion of a firm commitment underwritten initial public offering of the Company's shares of common stock at a price equal to or greater than $4.10 per share. In January 2018, the Company receivedshareholder consent from a majority of Series A convertible preferred stockholders consenting to the automatic conversion of the Series A convertible preferred stock upon the closing of a firmcommitment underwritten initial public offering of the Company's shares of common stock.

        Allholders of Series A convertible preferred stock as of June 30, 2016 began accruing a 3% stock dividend beginning on July 1, 2016. Subsequent acquirers beganaccruing on the date they acquired their respective shares. Accrued dividends shall be payable annually on December 31. On December 31, 2017, 950,046 shares of Series A convertible preferredstock were issued as dividends for the fiscal year 2017. A valuation of the Series A convertible stock was performed by an independent firm and assessed at $2.94 per share on the payment date and wasrecorded as dividends paid and offset to accumulated deficit in the amount of approximately $2,793,000. On December 31, 2016, 254,610 shares of Series A convertible preferred stock wereissued as dividends for the fiscal year 2016. A valuation of the Series A convertible stock was performed by an independent firm and assessed at $1.83 per share on the payment date and wasrecorded as dividends paid and offset to additional paid-in capital in the amount of approximately $465,000. For the three months ended March 31, 2018, the Company accrued approximately$817,000 as dividends payable for the 271,471 dividend shares that were accrued.

        Ofthe Series A convertible preferred stock sold during 2016 and 2017, 16,516,606 shares sold at $2.05 per share and 2,033,898 shares sold at $2.95 per share contain pricebased anti-dilution protection rights. Unless agreed to otherwise, if the Company issues additional securities at a purchase price less than the purchase price paid by these respective holders, theCompany shall issue additional preferred shares equal to the difference of the number of preferred shares that each respective shareholder would have received if they paid the subsequent lower price,and the number of share each respective shareholder originally received. The Company reviewed the embedded anti-dilution protection feature included in the Series A convertible preferred stocksold during 2016 pursuant to ASC 480, Distinguishing Liabilities From Equity, and ASC 815, Derivatives andHedging, and determined that the provisions of ASC 480 did not result in liability classification, the embedded anti-dilution protection feature did not meet the definition ofa derivative as there was no market for the Series A convertible preferred stock to be converted into cash and that the embedded anti-dilution protection feature did not require bifurcation.

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Table of Contents

Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

7. Convertible Preferred Stock and Preferred Stock Warrants (Continued)

        Theliquidation preference provisions of the Series A convertible preferred stock are considered contingent redemption provisions because there are certain elements that are notsolely within the control of the Company, such as a change in control of the Company. Accordingly, the Company has presented the Series A convertible preferred stock within the mezzanineportion of the accompanying consolidated balance sheets at the full liquidation value.

        OnAugust 12, 2016, the Company completed its first and initial closing under a private placement memorandum and sold 7,422,600 shares of its Series A convertible preferredstock at a price of $2.05 per share though a private offering memorandum for total gross proceeds of $15.2 million. In connection with this transaction, investors received 1,855,675 five yearwarrants exercisable into Series A convertible preferred stock. Also in connection with this first closing, the placement agent received 835,042 five year warrants to purchase Series Aconvertible preferred stock.

        Immediatelyfollowing the first closing, certain prior investors were issued ten year warrants exercisable into Series A convertible preferred stock. A total of 2,175,451 warrantswere issued to prior investors.

        OnDecember 12, 2016, the Company completed its second closing under a private placement memorandum and sold 6,654,981 shares of its Series A convertible preferred stock ata price of $2.05 per share though a private offering memorandum for total gross proceeds of $13.6 million. In connection with this transaction, investors received 1,663,748 five year warrantsexercisable into Series A convertible preferred stock. Also in connection with this second closing, the placement agent received 748,685 five year warrants.

        OnDecember 15, 2016, the Company issued 1,594,361 shares of Series A convertible preferred stock upon the maturity of the December 2016 convertible notes. In addition, allholders of December 2016 convertible notes were issued ten year warrants exercisable into Series A convertible preferred stock. A total of 192,171 warrants were issued to the investors.

        OnDecember 30, 2016, the Company completed its third closing under a private placement memorandum and sold 2,439,024 shares of its Series A convertible preferred stock ata price of$2.05 per share though a private offering memorandum for total gross proceeds of $5.0 million. In connection with this transaction, investors received 609,756 five year warrants exercisableinto Series A convertible preferred stock. Also in connection with this third closing, the placement agent received 274,391 five year warrants to purchase Series A convertible preferredstock. The proceeds of $5.0 million from the third closing was received in January 2017. As of December 31, 2016, the transaction was recorded as a stock subscription receivable in theequity section of the Company's balance sheet.

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Table of Contents

Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

7. Convertible Preferred Stock and Preferred Stock Warrants (Continued)

        FromJune through August of 2017, the Company sold 6,516,142 shares of Series A convertible preferred stock to various investors at prices ranging from $2.70 to $2.95 per sharefor total gross proceeds of $18.3 million and net proceeds of $16.6 million after financing costs. On July 12 2017, in conjunction with the sale of its Series A convertiblepreferred stock to one of the investors, the Company issued 370,370 warrants to purchase its Series A convertible preferred stock. The warrant has a term of five years from the issuance date.

        Allpreferred stock warrants have an exercise price of $2.26 per share except for the 370,370 warrants issued in July 2017 which have an exercise price of $2.97 per share.

        Ifby August 12, 2019 the Company has not yet consummated a firm commitment underwritten initial public offering of its common stock, then the number of all outstanding warrantsexercisable into Series A convertible preferred stock will increase by 100%.

Warrant Liability

        The Company evaluated the accounting treatment for the Series A convertible preferred stock warrants issued during 2016 and 2017, and thethree months ended March 31, 2018 and 2017. The Company concluded pursuant to its evaluation of ASC 480 that due to the contingent liquidation redemption feature in the underlyingSeries A convertible preferred stock not being solely within the control of the Company, the Series A convertible preferred stockwarrants issued were considered a liability. As a result, the Company has recorded the issuance of each Series A convertible preferred stock warrant as a warrant liability and the subsequentchanges in fair value to be recorded as a component in other expense. The warrant liability requires the Company to remeasure the value of the underlying warrants and report the effect of the changeson our operations until the warrants are exercised or expire. The primary underlying risk exposure pertaining to the warrants is the change in fair value of the underlying preferred stock for eachreporting period. The warrant liability was measured using the Monte Carlo valuation model.

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Table of Contents

Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

7. Convertible Preferred Stock and Preferred Stock Warrants (Continued)

        Thefollowing table (in thousands) summarizes the Company's activity and fair value calculations of its derivative warrants for the year ended December 31, 2017 and the threemonths ended March 31, 2018:

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Table of Contents

Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

8. Common Stock

        As of December 31, 2017, the Company had reserved the following common stock for future issuance:

        Asof March 31, 2018, the Company had reserved the following common stock for future issuance (unaudited):

        Allof the Company's outstanding preferred stock warrants contain a provision such that if the Company has not yet consummated a firm commitment underwritten initial public offering byAugust 12, 2019, the number of warrants will increase by 100%.

9. Stock-Based Compensation

        In May 2014, the Company adopted and the shareholders approved the 2014 Equity Incentive Plan (the 2014 Plan). Under the 2014 Plan, 1,500,000 shares of the Company's common stock havebeen reserved for the issuance of stock options to employees, directors, and consultants, under terms and provisions established by the Board of Directors. Under the terms of the 2014 Plan, optionsmay be granted at an exercise price not less than fair market value. For employees holding

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Table of Contents

Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

9. Stock-Based Compensation (Continued)

morethan 10% of the voting rights of all classes of stock, the exercise prices for incentive and nonstatutory stock options may not be less than 110% of fair market value, as determined by the Boardof Directors. The terms of options granted under the 2014 Plan may not exceed ten years.

        Inaddition, the 2014 Plan contains an "evergreen" provision allowing for an annual increase in the number of shares of our common stock available for issuance under the 2014 Plan on thefirst day of each fiscal year beginning in fiscal year 2015. The annual increase in the number of shares shall be equal to the greater of:

•

500,000 shares of our common stock; or



•

such number of shares as is equal to the number of shares sufficient to cause the option pool to equal 20% of the issued and outstanding commonstock of the Company, provided, however, that if on any calculation date the number of shares equal to 20% of the total issued and outstanding shares of common stock is less than the number of sharesof common stock available for issuance under the 2014 Plan, no change will be made to the aggregate number of shares of common stock issuable under the 2014 Plan for that year (such that the aggregatenumber of shares of common stock available for issuance under the 2014 Plan will never decrease).

        Thenumber of shares, terms, and vesting periods are determined by the Company's Board of Directors or a committee thereof on an option by option basis. Options generally vest ratablyover service periods of up to four years and expire ten years from the date of grant.

        TheCompany estimated the fair value of options using the BSM option valuation model. The fair value of employee options is being amortized on a straight line basis over the requisiteservice period of the awards. During the year ended December 31, 2017 and 2016, stock-based compensation expense for employees was approximately $1,303,000 and $778,000, respectively, andstock-based compensation expense for employee warrants was approximately $132,000 and $7,000, respectively. During the three months ended March 31, 2018 and 2017, stock-based compensationexpense for employee stock options was approximately $471,000 and $630,000, respectively, and stock-based compensation expense for employee warrants was $32,000 and $32,000, respectively.

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Table of Contents

Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

9. Stock-Based Compensation (Continued)

        Thefair value of the employee options granted during the year ended December 31, 2017 and 2016 and the three months ended March 31, 2018 and 2017 were estimated using thefollowing assumptions:

        Stockoption activity for the year ended December 31, 2017 and 2016 and the three months ended March 31, 2018 are represented in the following table:

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Table of Contents

Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

9. Stock-Based Compensation (Continued)

        Furtherinformation about the options outstanding and exercisable at March 31, 2018 is as follows:

        Duringthe year December 31, 2017 and 2016, the Company granted options to employees to purchase 889,916 and 1,311,000 shares with a weighted-average grant date fair value of$1.84 and $1.01 per share, respectively. During the three months ended March 31, 2018, the Company granted options to employees to purchase 1,232,199 shares with a weighted-average grant datefair value of $1.88 per share.

        Asof December 31, 2017 and March 31, 2018 there were total unrecognized compensation costs for employees of approximately $2,056,000 and $3,510,000, respectively, relatedto these options. These costs are expected to be recognized over a period of approximately 2.8 and 2.7 years, respectively. The aggregate intrinsic value, based on the fair market value of theCompany's common stock, of options outstanding and vested as of December 31, 2017 and March 31, 2018 was $4,057,000 and $4,079,000, respectively, and $2,690,000 and $3,205,000,respectively.

        TheCompany grants options to purchase common stock to consultants in exchange for services during the normal course of business. During the year ended December 31, 2017 and 2016,the Company granted options to consultants to purchase 130,000 and 93,200 shares, respectively.During the three months ended March 31, 2018, the Company did not grant any options to consultants.

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Table of Contents

Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

9. Stock-Based Compensation (Continued)

        The fair value of the options granted to consultants during the year ended December 31, 2017 and 2016 and the three months ended March 31, 2017 were estimated using thefollowing assumptions:

        Stock-basedcompensation expense related to stock options granted to consultants is recognized on a straight-line basis, as the stock options are earned. The Company issued options tonon-employees, which generally vest ratably over the time period the Company expects to receive services from the non-employee. The values attributable to these options are amortized over the serviceperiod and the unvested portion of these options was remeasured at each vesting date. During the year ended December 31, 2017 and 2016, stock-based compensation expense for consultants wasapproximately $173,000 and $73,000, respectively. During the three months ended March 31, 2018 and 2017, stock-based compensation expense for consultants was approximately $39,000 and $25,000,respectively.

10. Income Taxes

        On December 22, 2017, the Tax Cuts and Jobs Act of 2017 (the "Tax Act") was signed into law making significant changes to the Internal Revenue Code. Changes include, but are notlimited to, a corporate tax rate decrease from 34% to 21% (the "Rate Reduction") effective for tax years beginning after December 31, 2017. The Company reduced deferred tax assets atDecember 31, 2017 for the effect of the Rate Reduction. The Rate Reduction did not impact the Company's provision for income taxes for 2017 due to the full valuation allowance on deferred taxassets.

        StaffAccounting Bulletin No. 118 ("SAB 118") was issued to address the application of US GAAP in situations when a registrant does not have the necessaryinformation available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the Act. The Company determined that the$2,572,000 reduction in deferred tax assets resulting from Rate Reduction was both provisional and a reasonable estimate at December 31, 2017. Additionally, the Company is still in the processof analyzing

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Table of Contents

Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

10. Income Taxes (Continued)

certainprovisions of the Act including the application of new executive compensation limitation provisions under Internal Revenue Section 162(m). These items are subject to revisions fromfurther analysis of the Tax Act and interpretation of any additional guidance issued by the U.S. Treasury Department, IRS, FASB, and other standard-setting and regulatory bodies.

        Thefollowing summarizes the difference (in thousands) between the income tax expense and the amount computed by applying the statutory federal income tax rate of 34% to income beforeincome tax:

        Deferredincome taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts usedfor income tax purposes. Significant components of our deferred tax assets (in thousands) are as follows:

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Table of Contents

Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

10. Income Taxes (Continued)

        Basedon the available objective evidence, management believes it is more-likely-than-not that the deferred tax assets were not fully realizable as of December 31, 2017 and 2016.Accordingly, the Company has established a full valuation allowance against its deferred tax assets.

        Thenet change in the valuation allowance for the year ended December 31, 2017 and 2016 was $2,386,000 and $1,838,000, respectively.

        AtDecember 31, 2017, the Company has net operating loss carryforwards of $8,132,000 and $8,140,000 for federal and California state income tax purposes, respectively. The netoperating loss begins to expire in 2035 for federal tax and state tax purposes. At December 31, 2016, the Company has research credit carryforwards of $108,000 and $208,000 for federal andCaliforniastate income tax purposes, respectively. The federal credits begin to expire in 2035 and the state credits can be carried forward indefinitely.

        Utilizationof the net operating loss carryforwards and credits may be subject to an annual limitation due to the ownership change limitations provided by the Internal Revenue Code of1986, as amended (the "Code"), and similar state provisions. Any annual limitation may result in the expiration of net operating losses and credits before utilization.

        TheCompany is subject to taxation in the United States, California and the Netherlands. The Company remains subject to possible examination by tax authorities in these jurisdictions fortax years dating back to 2014. The Company does not have any pending tax examinations. Following the Company's adoption of ASC 740-10 regarding accounting for uncertainty in income taxes, the Companymade a comprehensive review of its portfolio of uncertain tax positions in accordance with the guidance. In this regard, an uncertain tax position represents the Company's expected treatment of a taxposition taken in a filed tax return, or planned to be taken in a future tax return, that has not been reflected in measuring income tax expense for financial reporting purposes. As a result of thatreview, the Company concluded there were no uncertain tax positions and no cumulative effect on retained earnings at the time of adoption.

        TheCompany recognizes interest and penalties related to income tax matters as a component of income tax expense. As of December 31, 2017, there were no significant accruedinterest and penalties related to uncertain tax positions.

11. Commitments and Contingencies

Leases

        The Company leases office and lab space in San Jose, California under an operating lease arrangement which can be terminated at any time with90 days' notice. The Company recognizes rent expense as incurred. Rent expense was approximately $299,000 and $285,000, for the year

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Table of Contents

Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

11. Commitments and Contingencies (Continued)

endedDecember 31, 2017 and 2016 and approximately $77,000 and $74,000 for the three months ended March 31, 2018 and 2017, respectively.

Indemnification

        In the normal course of business, the Company enters into contracts and agreements that contain a variety of representations and warranties andprovide for general indemnifications. The Company's exposure under these agreements is unknown because it involves claims that may be made against the Company in the future, but have not yet beenmade. To date, the Company has not paid any claims or been required to defend any action related to its indemnification obligations. However, the Company may incur charges in the future as a result ofthese indemnification obligations.

Contingencies

        From time to time, the Company may have certain contingent liabilities that arise in the ordinary course of its business activities. The Companyaccrues a liability for suchmatters when it is probable that future expenditures will be made and such expenditures can be reasonably estimated.

        Fromtime to time, the Company may be involved in various legal proceedings, claims and litigation arising in the ordinary course of business. As of December 31, 2017 andMarch 31, 2018, there were no pending legal proceedings.

Grant Income

        The Company receives various grants that are subject to audit by the grantors or their representatives. Such audits could result in requests forreimbursement for expenditures disallowed under the terms of the grant; however, management believes that these disallowances, if any, would be immaterial.

Cystic Fibrosis Foundation Agreement

        In December 2016, the Company received an award for up to $2,902,097 from the Cystic Fibrosis Foundation to advance research on potential drugsutilizing inhaled gallium citrate anti-infective. Under the award agreement, the Cystic Fibrosis Foundation will make payments to the Company as certain milestones are met. The award agreement alsocontains a provision whereby if the Company spends less on developing a potential drug utilizing inhaled gallium citrate anti-infective than the Company actually receives under this award agreement,the Company will be required to return the excess portion of the award to the Cystic Fibrosis Foundation. At the end of any reporting period, if the Company determines that the cumulative

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Table of Contents

Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

11. Commitments and Contingencies (Continued)

amountspent on this program is less than the cumulative cash received from the Cystic Fibrosis Foundation, the Company will record the excess amount received as a liability.

        Inthe event that development efforts are successful and the Company commercialized a drug from these related development efforts, the Company may be subject to pay to Cystic FibrosisFoundation a one-time amount equal to the awarded amount. Such amount shall be paid in as few as three but not more than five annual installments, as follows: within ninety days of the end of thecalendar year in which the First Commercial Sale occurs, and within ninety days of the end of each subsequent calendar year until the amount is paid, Aridis shall pay up to one-third of the amount butnot more than 5% of net sales from compounds containing gallium citrate or gallium nitrate citrate as an active ingredient for that calendar year (except that in the fifth installment, if any, theCompany shall pay the remaining unpaid portion of the awarded amount).

        Inaddition to the amount payable above, the Company will pay to Cystic Fibrosis Foundation a one-time amount equal to the amount of funding from Cystic Fibrosis Foundation under theagreement, within sixty days after the end of the first calendar year during which aggregate net sales of compounds containing gallium citrate or gallium nitrate citrate as an active ingredient exceed$100 million.

        Inthe event that Aridis licenses rights to the product in the field to a third party, sells the product, or consummates a change of control transaction prior to the first commercialsale, Aridis shall pay to Cystic Fibrosis Foundation an amount equal to two times the actual awarded amount under the agreement, if the change of control transaction occurs prior to the completion ofthe first Phase IIb (or equivalent) clinical study with respect to the product; and four times the actual awarded amount if the change of control transaction occurs after the completion of thePhase IIb clinical trial specified above. The payment shall be made within sixty days after the closing of such a transaction.

Joint Venture Agreement

        In February 2018, the Company entered into a joint venture agreement with Shenzen Hepalink Pharmaceutical Group Co., Ltd., the Company's largestshareholder and a Chinese entity, for developing and commercializing products for infectious diseases. Under the terms of the agreement, the Company is obligated to contribute $1 million and thelicensing of its technology for use in the joint venture entity and will initially own 49% of the joint venture entity.

12. 401(k) plan

        We maintain a defined contribution employee retirement plan, or 401(k) plan, for our employees, effective as of October 1, 2016. Our named executive officers are eligible toparticipate

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Table of Contents

Aridis Pharmaceuticals, Inc.

Notes to Consolidated Financial Statements (Continued)

(Information as of March 31, 2018 and for the periods ended
March 31, 2018 and 2017 are Unaudited)

12. 401(k) plan (Continued)

inthe 401(k) plan on the same basis as our other employees. The 401(k) plan is intended to qualify as a tax-qualified plan under Section 401(k) of the Internal Revenue Code. The 401(k) planprovides that each participant may make pre-tax deferrals from his or her compensation up to the statutory limit, which is $18,500 for calendar year 2018, and other testing limits. Participants thatare 50 years or older can also make "catch-up" contributions, which in calendar year 2018 may beup to an additional $6,000 above the statutory limit. Although the 401(k) plan provides for discretionary matching and profit sharing contributions, we currently do not make either type ofcontribution to the 401(k) plan. Participant contributions are held and invested, pursuant to the participant's instructions, by the plan's trustee.

13. Subsequent Events

        The Company considers events or transactions that occur after the balance sheet date but prior to the issuance of the financial statements to provide additional evidence relative tocertain estimates or to identify matters that require additional disclosure. For its financial statements as of December 31, 2017 and for the year then ended, the Company has completed anevaluation of all subsequent events through April 19, 2018, the date these financial statements were available to be issued, to ensure that the financial statements include appropriatedisclosure of events both recognized in the financial statements as of December 31, 2017, and events which occurred subsequently but were not recognized in the financial statements.

14. Subsequent Events (Unaudited)

        In July 2018, the Company reevaluated its cash position and financial projections and concluded that there is substantial doubt about the Company's ability to continue as a going concernfor the one-year period following the date that these interim consolidated financial statements were issued. The accompanying interim consolidated financial statements and notes have been preparedassuming that the Company will continue as a going concern. The accompanying interim consolidated financial statements and notes do not include any adjustments to reflect the possible future effectson the recoverability and classification of assets or the amounts and classification of liabilities that may result from the possible inability of the Company to continue as a going concern.

        Thejoint venture received regulatory approval in China and the joint venture company was formed on July 2, 2018.

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            Shares

Common Stock

Aridis Pharmaceuticals, Inc.

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PRELIMINARY PROSPECTUS

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                    , 2018

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PART II — INFORMATION NOT REQUIRED IN PROSPECTUS

Item 13.    Other Expenses of Issuance and Distribution

        The following table sets forth all expenses, other than the underwriting discounts and commissions, payable by the registrant in connection withthe sale of the common stock being registered. All the amounts shown are estimates except the SEC registration fee and the FINRA filing fee.

Item 14.    Indemnification of Directors and Officers

        Section 145 of the Delaware General Corporation Law authorizes a court to award, or a corporation's board of directors to grant,indemnity to directors and officers in terms sufficiently broad to permit such indemnification under certain circumstances for liabilities, including reimbursement for expenses incurred, arising underthe Securities Act.

        Ourcertificate of incorporation provides that we will indemnify our directors to the fullest extent permitted by Delaware law.

        Inaddition, as permitted by Section 145 of the Delaware General Corporation Law our bylaws provide that we will indemnify our directors and executive officers for serving us inthose capacities or for serving other business enterprises at our request, to the fullest extent permitted by Delaware law. Delaware law provides that a corporation may indemnify such person if suchperson acted in good faith and in a manner such person reasonably believed to be in or not opposed to the best interests of the corporation and, with respect to any criminal proceeding, had noreasonable cause to believe such person's conduct was unlawful. We may, in our discretion, indemnify other officers, employees and agents in those circumstances where indemnification is permitted byapplicable law. We are required to advance expenses, as incurred, to our directors and executive officers in connection with defending a proceeding, except that such directors or executive officersshall undertake to repay such advances if it is ultimately determined that such person is not entitled to indemnification. We will not be obligated pursuant to our bylaws to indemnify any director orexecutive officer in connection with any proceeding (or part thereof) initiated by such person unless (i) such indemnification is expressly required to be made by law, (ii) theproceeding was authorized by our Board of Directors, (iii) such indemnification is provided by us, in our sole discretion, pursuant to the powers vested in the corporation under

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applicablelaw or (iv) such indemnification is required to be made pursuant to our restated bylaws. The rights conferred in our bylaws are not exclusive, and we are authorized to enter intoindemnification agreements with our directors, officers, employees and agents and to obtain insurance to indemnify such persons. We may not retroactively amend our bylaw provisions to reduce ourindemnification obligations to directors, officers, employees and agents. We may, to the fullest extent permitted by the Delaware Law, purchase and maintain insurance on behalf of any officer,director, employee and agent against any liability which may be asserted against such person.

        Inany underwriting agreement we enter into in connection with the sale of common stock being registered hereby, the underwriters will agree to indemnify, under certain conditions, us,our directors, our officers and persons who control us, within the meaning of the Securities Act, against certain liabilities.

Item 15.    Recent Sales of Unregistered Securities

        The following sets forth information regarding all unregistered securities sold from May 21, 2014 to July 13, 2018.

Founders Shares and Preferred Stock Issuances

        On May 21, 2014, upon the Company's conversion from an LLC to a C corporation, 8,828,020 shares of common stock were issued to thefounders of the Company. On July 28, 2014, these shares were converted, on a one for one basis, into shares of Series A convertible preferred stock. Each share of Series Aconvertible preferred stock is entitled to voting rights equivalent to the number of shares of common stock into which each share can be converted. The Series A convertible preferred stock isconvertible at the holder's option at any time into common stock on a one for one basis. Upon the liquidation, dissolution or winding up of the business of the Company, whether voluntary orinvoluntary, each holder shall be entitled to receive, for each share thereof, out of assets of the Company legally available therefore, a preferential amount in cash equal to (and not more than)$2.05 per share. Conversion of Series A convertible preferred stock is automatic upon the closing of an underwritten public offering with proceeds equal to or greater than $4.10 per share.Holders of the preferred stock, in preference to the holders of common stock, are entitled to receive dividends, when and if declared by the Board of Directors.

Private Placement I

        On May 31, 2014, we closed a private financing for $3,500,000, which was a private placement of 14 units each consisting of (i) a8% convertible unsecured term note in the principal amount of $250,000 convertible into shares of our common stock and (ii) a five-year warrant to purchase shares of common stock. In November2014, we entered into exchange agreements with each holder of the May 2014 notes whereby the May 2014 notes were exchanged for new notes convertible into our Series A Preferred Stock. The newnotes matured in May 2015. We issued an aggregate of 839,024 shares of Series A Preferred Stock and $90,000 upon maturity of the notes.

        Theexercise price of the warrants is $4.40. The exercise price is subject to adjustment in certain circumstances. The number of shares issuable upon the exercise of a warrant will beequal to the principal debt balance borrowed divided by the applicable exercise price.

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Private Placement II

        On August 12, 2014, we closed a private financing for $3,250,000, which was a private placement of 13 units with each unit consisting of(i) an 8% convertible unsecured term note in the principal amount of $250,000 convertible into shares of our preferred stock and (ii) a three-year warrant to purchase shares of commonstock.

        Weissued an aggregate of 697,385 shares of Series A convertible preferred stock upon maturity of the notes. The exercise price of the warrants was $5.03 per share. All warrants expiredunexercised on August 12, 2017.

Private Placement III

        On December 15, 2015, we closed a private financing for $3,750,000, which was a private placement of 15 units each consisting of annon-interest bearing unsecured term note in the principal amount of $250,000 convertible into shares of our common stock and (ii) a five-year warrant to purchase shares of common stock. Weissued an aggregate of 1,594,361 shares of Series A Preferred Stock upon maturity of the notes. The exercise price of the warrants is $2.35. The exercise price is subject to adjustment incertain circumstances. The number of shares issuable upon the exercise of a warrant will be equal to the principal debt balance borrowed divided by the applicable exercise price.

Other Issuances

        In September 2014, we issued a total of 258,000 shares of common stock to consultants as full payment of notes payable to the consultants forservices performed in prior periods.

        InSeptember 2014, we issued a total of 839,781 options to purchase shares of our common stock under our 2014 Plan to employees and consultants.

        InDecember 2014, we issued a total of options to purchase 2,000 shares of our common stock under our 2014 Plan to an employee.

        InMarch 2015, we issued a total of 702,515 options to purchase shares of our common stock under our 2014 Plan to employees and consultants.

        InMay 2015, we issued a total of 9,086 shares of common stock to consultants as payment for services.

        InMay 2015, we issued a total of 839,024 shares of Series A convertible preferred stock when the May 2014 convertible notes matured.

        InJune 2015, we issued a total of 80,030 options to purchase shares of our common stock under our 2014 Plan to employees and consultants.

        InSeptember 2015, we issued a total of 32,199 options to purchase shares of our common stock under our 2014 Plan to consultants.

        InDecember 2015, we issued a total of 165,700 options to purchase shares of our common stock under our 2014 Plan to employees and consultants.

        InMarch 2016, we issued a total of 86,500 options to purchase shares of our common stock under our 2014 Plan to employees and consultants.

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        InJuly 2016, we issued a total of 92,700 options to purchase shares of our common stock under our 2014 Plan to employees and consultants.

        InAugust 2016, the Company completed its First Closing under a private placement memorandum and sold 7,422,603 shares of its Series A convertible preferred stock. The investorsreceived one five year warrant exercisable for one-quarter (1/4) of a share of Series A convertible preferred stock at an exercise price of $2.26 per share. If by the third anniversary date ofthe First Closing, the Company has not yet consummated a firm commitment underwritten initial public offering of its Common Stock, then each Warrant shall become exercisable for one-half (1/2) of ashare of common stock. The Warrants shall be exercisable into Series A preferred stock; provided however, that if a prior investor converts shares of Series A preferred stock for anyreason, the Warrants issued to him in connection with these shares shall be automatically exercisable into common stock. In addition, a total of 2,175,451 ten year warrants were issued to priorinvestors as part of the closing. In connection with this First Closing, the placement agent received 835,042 five year warrants to purchase Series A preferred stock.

        InOctober 2016, we issued a total of 1,225,000 options to purchase shares of our common stock under our 2014 Plan to employees and consultants.

        InDecember 2016, the Company completed its Second Closing under a private placement memorandum and sold 6,654,981 shares of its Series A convertible preferred stock. Theinvestors received one five year warrant exercisable for one-quarter (1/4) of a share of Series A convertible preferred stock at an exercise price of $2.26 per share. If by the thirdanniversary date of the First Closing, the Company has not yet consummated a firm commitment underwritten initial public offering of its Common Stock, then each Warrant shall become exercisable forone-half (1/2) of a share of Common Stock. In connection with this Second Closing, the placement agent received 748,685 five year warrants to purchase Series A Preferred Stock. In addition,upon the completion of the Second Closing, the Company's Vice Chairman was awarded 1,507,302 ten year warrants to purchase shares of the Company's common stock.

        InDecember 2016, the Company completed its Third Closing under a private placement memorandum and sold 2,439,024 shares of its Series A convertible preferred stock. The investorsreceived one five year warrant exercisable for one-quarter (1/4) of a share of Series A convertible preferred stock at an exercise price of $2.26 per share. If by the third anniversary date ofthe First Closing, the Company has not yet consummated a firm commitment underwritten initial public offering of its common stock, then each warrant shall become exercisable for one-half (1/2) of ashare of common stock. . In connection with this Third Closing, the placement agent received 274,391 five year warrants to purchase Series A preferred stock.

        InDecember 2016, we issued a total of 1,594,361 shares of Series A convertible preferred stock when the December 2015 convertible notes matured.

        InMarch 2017, we issued a total of 217,000 options to purchase shares of our common stock under our 2014 Plan to employees and consultants.

        InJune 2017, we issued a total of 40,000 options to purchase shares of our common stock under our 2014 Plan to employees.

        FromJune 2017 to August 2017, the Company sold 6,516,142 shares of its Series A convertible preferred stock to various investors.

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        InJuly 2017, the Company issued to an investor 370,370 five year warrants to purchase its Series A convertible preferred stock.

        InSeptember 2017, we issued a total of 520,000 options to purchase shares of our common stock under our 2014 Plan to employees and consultants.

        InDecember 2017, we issued a total of 242,916 options to purchase shares of our common stock under our 2014 Plan to employees and consultants.

        InJanuary 2018, we issued a total of 750,000 options to purchase shares of our common stock under our 2014 Plan to an employee.

        InMarch 2018, we issued a total of 482,199 options to purchase shares of our common stock under our 2014 Plan to employees.

        Unlessotherwise stated, the sales of the above securities were deemed to be exempt from registration under the Securities Act in reliance upon Section 4(a)(2) of the SecuritiesAct (or Regulation D promulgated thereunder), or Rule 701 promulgated under Section 3(b) of the Securities Act as transactions by an issuer not involving any public offering orpursuant to benefit plans and contracts relating to compensation as provided under Rule 701. The recipients of the securities in each of these transactions represented their intentions toacquire the securities for investment only and not with a view to or for sale in connection with any distribution thereof, and appropriate legends were placed upon the stock certificates issued inthese transactions.

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Item 16.    Exhibits and Financial Statement Schedules

(a)

Exhibits

EXHIBIT INDEX

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Item 17.    Undertakings

        Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers and controlling persons ofthe registrant pursuant to the foregoing provisions, or otherwise, the registrant has been advised that in the opinion of the SEC such indemnification is against public policy as expressed in theSecurities Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the registrant of expenses incurred or paid by adirector, officer or controlling personof the registrant in the successful defense of any action, suit or proceeding) is asserted by such director, officer or controlling person in connection with the securities being registered, theregistrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification byit is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue.

        Theundersigned registrant hereby undertakes that:

        (1)   Forpurposes of determining any liability under the Securities Act of 1933, the information omitted from the form of prospectus filed as part of this registrationstatement in reliance upon Rule 430A and contained in a form of prospectus filed by the registrant pursuant to Rule 424(b)(1) or (4) or 497(h) under the Securities Act shall bedeemed to be part of this registration statement as of the time it was declared effective.

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        (2)   Forthe purpose of determining any liability under the Securities Act of 1933, each post-effective amendment that contains a form of prospectus shall be deemed to be anew registration statement relating to the securities offered therein, and the offering of such securities at that time shall be deemed to be the initial bona fide offering thereof.

        (3)   Toprovide to the underwriters at the closing specified in the Underwriting Agreement, certificates in such denominations and registered in such names as required by theunderwriters to permit prompt delivery to each purchaser.

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SIGNATURES

        Pursuant to the requirements of the Securities Act of 1933, as amended, the registrant has duly caused this RegistrationStatement on Form S-1 to be signed on its behalf by the undersigned, thereunto duly authorized in the City of San Jose, State of California, on the 18^th day of July, 2018.

POWER OF ATTORNEY

        We, the undersigned officers and directors of Aridis Pharmaceuticals, Inc., hereby severally constitute and appoint VuTruong and Fred Kurland, and each of them singly, our true and lawful attorneys with full power to any of them, and to each of them singly, to sign for us and in our names, in the capacities indicatedbelow, the Registration Statement on Form S-1 filed herewith and any and all pre-effective and post-effective amendments to said registration statement and any subsequent registration statementfiled pursuant to Rule 462(b) under the Securities Act of 1933, as amended, and to file the same with all exhibits thereto, and the other documents in connection therewith, with the Securitiesand Exchange Commission, and generally to do all such things in our name and behalf in our capacities as officers and directors to enable Aridis Pharmaceuticals, Inc. to comply with theprovisions of the Securities Act of 1933, as amended, and all requirements of the Securities and Exchange Commission, hereby ratifying and confirming our signatures as they may be signed by our saidattorneys, or any of them, to said registration statement and any and all amendments thereto.

        Pursuantto the requirements of the Securities Act of 1933, as amended, this Registration Statement on Form S-1 has been signed by the following persons in the capacities and onthe dates indicated below.

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