Filed Pursuant to Rule 424(b)(4)
Registration No.: 333-223920

PROSPECTUS

6,000,000 American Depositary Shares

Representing 30,000,000 Ordinary Shares

We are offering 6,000,000 American Depositary Shares, or ADSs. Each ADS represents five of our ordinary shares. The ADSs will be evidenced by American Depositary Receipts, or ADRs. This is the initial public offering of our ADSs. No public market has previously existed for our ADSs. Our ordinary shares are currently listed on the Taipei Exchange, or TPEx. On April 13, 2018, the last reported sale price of our ordinary shares on the TPEx was NT$47.30 per share, or approximately $1.61 per share, based on an exchange rate of NT$29.30 to $1.00. The initial public offering price is $7.03 per ADS. Pursuant to the relevant Taiwan rules and practices, this represents at least 90% of the closing price of our ordinary shares on the date of this prospectus.

We have applied to list our ADSs on The Nasdaq Global Market under the symbol “ASLN.”

Investing in our ADSs involves a high degree of risk. Before buying any ADSs, you should carefully read the discussion of material risks of investing in our ADSs in “Risk Factors” beginning on page 13 of this prospectus.

We are an “emerging growth company” and a “foreign private issuer” as defined under the federal securities laws and, as such, will be subject to reduced public company reporting requirements. See “Prospectus Summary—Implications of Being an Emerging Growth Company and a Foreign Private Issuer” for additional information.

Neither the Securities and Exchange Commission nor any other regulatory body has approved or disapproved of these securities or passed upon the accuracy or adequacy of this prospectus. Any representation to the contrary is a criminal offense.

Delivery of the ADSs is expected to be made on or about May 8, 2018. We have granted the underwriters an option, exercisable at any time through and until one day before the closing date of this offering, to purchase an additional 900,000 ADSs, solely to cover over-allotments, if any.

The date of this prospectus is May 4, 2018.

TABLE OF CONTENTS

We are responsible for the information contained in this prospectus and any free writing prospectus we prepare or authorize. We have not, and the underwriters have not, authorized anyone to provide you with different information, and we and the underwriters take no responsibility for any other information others may give you. We are not, and the underwriters are not, making an offer to sell our ADSs in any jurisdiction where the offer or sale is not permitted. You should not assume that the information contained in this prospectus is accurate as of any date other than the date on the front cover of this prospectus, regardless of the time of delivery of this prospectus or the sale of any ADSs.

For investors outside the United States: Neither we nor the underwriters have done anything that would permit this offering or possession or distribution of this prospectus in any jurisdiction, other than the United States, where action for that purpose is required. Persons outside the United States who come into possession of this prospectus must inform themselves about, and observe any restrictions relating to, the offering of the ADSs and the distribution of this prospectus outside the United States.

We are incorporated under the laws of the Cayman Islands as an exempted company with limited liability and a majority of our outstanding securities are owned by non-U.S. residents. Under the rules of the U.S. Securities and Exchange Commission, or SEC, we currently qualify for treatment as a “foreign private issuer.” As a foreign private issuer, we will not be required to file periodic reports and financial statements with the SEC as frequently or as promptly as domestic registrants whose securities are registered under the Securities Exchange Act of 1934, as amended, or the Exchange Act.

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Through and including May 29, 2018 (the 25th day after the date of this prospectus), all dealers that effect transactions in these securities, whether or not participating in this offering, may be required to deliver a prospectus. This is in addition to the dealers’ obligation to deliver a prospectus when acting as underwriters and with respect to their unsold allotments or subscriptions.

ABOUT THIS PROSPECTUS

Unless otherwise indicated or the context otherwise requires, all references in this prospectus to the terms “ASLAN,” “ASLAN Pharmaceuticals,” “the company,” “we,” “us” and “our” refer to ASLAN Pharmaceuticals Limited and its subsidiaries.

PRESENTATION OF FINANCIAL INFORMATION

Our consolidated financial statements have been prepared in accordance with International Financial Reporting Standards, or IFRS, as issued by the International Accounting Standard Board, or IASB, which may differ in material respects from generally accepted accounting principles in other jurisdictions, including the United States.

Our functional currency is the U.S. dollar. Unless otherwise specified, all monetary amounts presented are in U.S. dollars. All references in this prospectus to “$” mean U.S. dollars, all references in this prospectus to “NT$” mean New Taiwan dollars, the legal currency of the Republic of China, or ROC, and all references in this prospectus to “SG$” mean Singapore dollars, the legal currency of Singapore. The translation of the trading price of our common stock on the TPEx from New Taiwan dollars to U.S. dollars was made at a rate of NT$29.30 to $1.00, based on the exchange reported by the Wall Street Journal as of the closing price of our common stock on the TPEx on April 13, 2018. All other translations from New Taiwan dollars to U.S. dollars in this prospectus were made at a rate of NT$29.66 to $1.00, based on the exchange rate reported by the Wall Street journal on December 29, 2017. No representation is made that the New Taiwan dollar amounts referred to herein could have been or could be converted into U.S. dollars at any particular rate or at all. Any discrepancies in any table between totals and sums of the amounts listed are due to rounding.

We have made rounding adjustments to some of the figures included in this prospectus. Accordingly, numerical figures shown as totals in some tables may not be an arithmetic aggregation of the figures that preceded them.

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RISK FACTORS

An investment in our ADSs involves a high degree of risk. You should carefully consider the following information about these risks, together with the other information appearing elsewhere in this prospectus, before deciding to invest in our ADSs. The occurrence of any of the following risks could have a material adverse effect on our business, financial condition, results of operations and future growth prospects. In these circumstances, the market price of our ADSs could decline, and you may lose all or part of your investment.

Risks Related to Our Financial Condition and Need for Additional Capital

We have incurred significant losses since our inception and anticipate that we will continue to incur significant losses for the foreseeable future.

We are a clinical-stage oncology-focused biopharmaceutical company based in Singapore developing novel therapeutics for global markets. We target diseases that are both highly prevalent in Asia and orphan indications in the United States and Europe. Investment in biopharmaceutical product development is highly speculative because it entails substantial upfront capital expenditures and significant risk that any potential product candidate will not demonstrate adequate effectiveness in the targeted indication or an acceptable safety profile, gain regulatory approval or become commercially viable. All of our product candidates will require substantial additional development time and resources before we would be able to apply for or receive regulatory approvals and begin generating revenue from product sales. We are not profitable and have incurred significant net losses in each year since our inception, including net losses of $9.0 million and $39.9 million for fiscal years 2016 and 2017, respectively. As of December 31, 2017, we had an accumulated deficit of $90.3 million.

We have devoted substantially all our financial resources to developing our product candidates and targeted discovery work, including preclinical development activities and clinical trials. We expect to continue to incur substantial and increased expenses, losses and negative cash flows as we expand our development activities and advance our clinical programs, particularly with respect to our planned clinical development for varlitinib, ASLAN003 and ASLAN004, as well as the ASLAN005 and Modybodies discovery programs. If our product candidates are not successfully developed or commercialized, including because of a lack of capital, or if we do not generate enough revenue following marketing approval, we will not achieve profitability and our business may fail. Even if we successfully obtain regulatory approval to market our product candidates in the United States and Europe, our revenue will also be heavily dependent upon the size of the markets outside of the United States and Europe, in particular China and Japan, as well as our ability to obtain market approval and achieve commercial success in those markets.

We currently do not generate any revenue from product sales, have generated only limited revenue since inception, and may never be profitable.

We do not anticipate generating revenue from sales of our proprietary product candidates for the foreseeable future. Our ability to generate future revenue from product sales depends on our success in completing clinical development of, obtaining regulatory approval for, and launching and successfully commercializing any product candidates.

Because of the numerous risks and uncertainties associated with pharmaceutical product development, we are unable to predict the timing or amount of increased expenses, when, or if, we will begin to generate revenue from product sales, or when, or if, we will be able to achieve or maintain profitability. In addition, our expenses could increase beyond planned levels if we are required by the U.S. FDA to perform studies in addition to those that we currently anticipate or if such studies are larger, take longer or are otherwise more expensive to conduct than we expect.

Even if one or more of our product candidates is approved for commercial sale, to the extent we do not engage a third-party collaborator, we anticipate incurring significant costs associated with commercializing any approved

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product candidate. Even if we are able to generate revenue from the sale of any approved products, we may not become profitable and may need to obtain additional funding to continue operations.

We will need to obtain substantial additional financing for our operations, and if we fail to obtain additional financing, we may be forced to delay, reduce or eliminate our product development programs or commercialization efforts.

Developing pharmaceutical products, including conducting preclinical studies and clinical trials, is expensive and we have consumed substantial amounts of capital since inception. To date, we have financed our operations through government subsidies and grants, collaboration payments and the sale of equity securities and convertible debt. We will need substantial additional financing to continue our operations and do not expect revenues from product sales or potential licensing transactions to be sufficient to offset our development expenses as we advance our clinical programs, including varlitinib.

We estimate that the net proceeds from this offering will be approximately $36.8 million, based on an initial public offering price of $7.03 per ADS and after deducting the underwriting discounts and commissions and estimated offering expenses payable by us. As of December 31, 2017, we had cash and cash equivalents of approximately $50.6 million and working capital of $44.7 million (in each case without taking into account the initial upfront payment of $12.0 million which we made to Array in January 2018). Based upon 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 operating expenses and capital requirements for at least the next 12 months. Regardless of our expectations as to how long our net proceeds from this offering will fund our operations, changing circumstances beyond our control may cause us to consume capital more rapidly than we currently anticipate. For example, our clinical trials may encounter technical, enrollment or other difficulties that could increase our development costs more than we expect. We may also incur expenses as we create additional infrastructure to support our planned commercialization efforts and our operations as a U.S. public company. In any event, we will require additional capital prior to completing pivotal studies of (except with respect to varlitinib in biliary tract cancer), filing for regulatory approval for, or commercializing, varlitinib, ASLAN003, ASLAN004 or any of our other preclinical product candidates.

We cannot guarantee that future financing will be available in sufficient amounts or on terms acceptable to us, if at all. If we are unable to raise additional capital when required or on acceptable terms, we may be required to:

If we are unable to raise additional capital in sufficient amounts or on terms acceptable to us, we will be prevented from pursuing development and commercialization efforts, which will have an adverse effect on our business, operating results and prospects.

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Risks Related to Clinical Development and Regulatory Approval

We are heavily dependent on the success of varlitinib, as well as ASLAN003 and ASLAN004. We cannot give any assurance that any of varlitinib, ASLAN003 or ASLAN004 will successfully complete clinical development or receive regulatory approval, which is necessary before they can be commercialized.

Our business and future success is substantially dependent on our ability to successfully develop, obtain regulatory approval for, and successfully commercialize our lead program, varlitinib, as well as ASLAN003 and ASLAN004. Any delay or setback in the development of any of our product candidates, could adversely affect our business and cause the price of our ADSs or ordinary shares to decline. Should our planned clinical development of our more advanced product candidates fail to be completed in a timely manner or at all, we will need to rely on our other product candidates, which will require additional time and resources to obtain regulatory approval and proceed with commercialization. We cannot assure you that our planned clinical development for varlitinib or our other product candidates will be completed in a timely manner, or at all, or that we will be able to obtain approval for varlitinib or any of our product candidates from the U.S. FDA, the China Food and Drug Administration, or CFDA, or any comparable foreign regulatory authority.

Clinical development is a lengthy and expensive process with an uncertain outcome, and results of earlier studies and trials may not be predictive of future trial results. Failure can occur at any stage of clinical development. We have never completed a pivotal clinical trial for our product candidates or submitted a New Drug Application, or NDA, or a Biologics License Application, or BLA, to the U.S. FDA or similar drug approval filings to comparable foreign authorities.

Clinical testing is expensive and can take many years to complete, and its outcome is inherently uncertain. Failure can occur at any time during the clinical trial process. The results of preclinical studies and early clinical trials of our product candidates may not be predictive of the results of subsequent clinical trials. We have a limited operating history and to date have not demonstrated our ability to complete large scale pivotal clinical trials.

Product candidates in 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. In addition to the safety and efficacy traits of any product candidate, clinical trial failures may result from a multitude of factors including flaws in trial design, dose selection, placebo effect and patient enrollment criteria. A number of companies in the biopharmaceutical industry have suffered significant setbacks in advanced clinical trials due to lack of efficacy or adverse safety profiles, notwithstanding promising results in earlier trials. Based upon negative or inconclusive results, we or any potential future collaborator may decide, or regulators may require us, to conduct additional clinical trials or preclinical studies. In addition, data obtained from trials and studies are susceptible to varying interpretations, and regulators may not interpret our data as favorably as we do, which may delay, limit or prevent regulatory approval. Our future clinical trials may not be successful.

If any product candidate is found to be unsafe or lack efficacy, we will not be able to obtain regulatory approval for it and our business may be materially harmed. For example, if the results of our ongoing pivotal studies for varlitinib in biliary tract cancer and gastric cancer, our planned Phase 2 clinical trial of varlitinib in colorectal cancer, our ongoing Phase 2 clinical trial of ASLAN003 in AML, our planned Phase 1 clinical trial of ASLAN004 in severe atopic dermatitis and asthma, or any other clinical trials for these product candidates demonstrate unexpected safety findings or do not achieve the primary efficacy endpoints, the prospects for approval of these product candidates, as well the price of our ADSs and ordinary shares and our ability to create shareholder value would be materially and adversely affected.

In some instances, there can be significant variability in safety and/or efficacy results between different trials of the same product candidate due to numerous factors, including changes in trial protocols, differences in composition of the patient populations, adherence to the dosing regimen and other trial protocols and the dropout rate among clinical trial participants. For example, we could be required to use a primary endpoint in our pivotal

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studies that is different from endpoints in our Phase 2 clinical trials, which could result in negative or less compelling efficacy results in pivotal trials despite promising results in Phase 2 clinical trials. We do not know whether any future clinical trials we may conduct will demonstrate consistent or adequate efficacy and safety to obtain regulatory approval to market our product candidates. If we are unable to bring any of our current or future product candidates to market, our ability to create long-term shareholder value will be limited.

Delays in clinical trials are common and have many causes, and any delay could result in increased costs to us and jeopardize or delay our ability to obtain regulatory approval and commence product sales.

We may experience delays in clinical trials of our product candidates. Our planned clinical trials may not begin on time, have an effective design, enroll a sufficient number of patients, or be completed on schedule, if at all. Our clinical trials can be delayed for a variety of reasons, including:

We could also experience delays if physicians encounter unresolved ethical issues associated with enrolling patients in clinical trials of our product candidates in lieu of prescribing existing treatments that have established safety and efficacy profiles. Further, a clinical trial may be suspended or terminated by us, the IRBs for the institutions in which such trials are being conducted, any data monitoring committee for such trial, or by the U.S. FDA, CFDA or other regulatory authorities due to a number of factors, including failure to conduct the clinical trial in accordance with regulatory requirements or our clinical protocols, inspection of clinical trial or manufacturing sites by the U.S. FDA, CFDA or other regulatory authorities resulting in the imposition of a clinical hold, unforeseen safety issues or adverse side effects, failure to demonstrate a benefit from using a product candidate, changes in governmental regulations or administrative actions or lack of adequate funding to continue the clinical trial. Furthermore, we rely on CROs and clinical trial sites to ensure the proper and timely conduct of our clinical trials and while we have agreements governing their committed activities, we have limited influence over their actual performance. If we experience termination of, or delays in the completion of, any clinical trial of our product candidates, the commercial prospects for our product candidates will be harmed, and our ability to generate product revenues will be delayed. In addition, any delays in completing our clinical trials will increase our costs and slow down our product development and approval process. Any of these occurrences may harm our business, prospects, financial condition and results of operations significantly. Many of the factors that cause, or lead to, a delay in the commencement or completion of clinical trials may also ultimately lead to the denial of regulatory approval for our product candidates.

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Because we have multiple product candidates in our clinical pipeline and are considering a variety of target indications, 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 for which 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 and specific indications that we believe are the most promising. As a result, we may forego or delay pursuit of opportunities with other product candidates or other indications that later prove to have 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 our resources on other research programs and product candidates for specific indications that ultimately do not yield any commercially viable products. For example, one component of our business strategy is to build a broad immuno-oncology portfolio based on antibodies and antibody fragments which inhibit specific immune checkpoints in ways that we believe will enable us to simultaneously target multiple pathways. However, these antibodies and antibody fragments have not been proven and we cannot assure you that they will be viable candidates for preclinical development, that we will be able to target multiple pathways simultaneously or that our estimates for the resultant pipeline will prove accurate. In addition, the costs, time and resources required to successfully move these antibodies and antibody fragments into development may be greater than our estimates. Furthermore, if we do not accurately evaluate the commercial 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 in cases in which it would have been more advantageous for us to retain sole development and commercialization rights.

Our product candidates may cause adverse events or have other properties that could delay or prevent their regulatory approval or limit the scope of any approved label or market acceptance.

Adverse events, or AEs, caused by our product candidates or other potentially harmful characteristics of our product candidates could cause us, other reviewing entities, clinical trial sites or regulatory authorities to interrupt, delay or halt clinical trials and could result in the denial of regulatory approval. For example, across all varlitinib clinical trials, the most commonly occurring drug-related AEs as of December 31, 2017 were fatigue (43% of patients with any grade, 6% with grade 3 or 4), nausea (43% of patients with any grade, 2% with grade 3 or 4) and diarrhea (39% of patients with any grade, 4% with grade 3 or 4). Grade refers to the severity of the AE, with grade 3 indicating a severe or medically significant but not immediately life-threatening AE, grade 4 indicating an AE with potentially life-threatening consequences, and grade 5 meaning patient death.

Patients admitted to our varlitinib clinical trials are experiencing later stages of cancer and may be in a diminished physical state prior to entering our clinical trials, which put them at increased risk of death. These patients may die while receiving our drug candidates. In such circumstances, it may not be possible to exclude with certainty a causal relationship to varlitinib. For example, across our varlitinib clinical trials, three patient deaths (grade 5) that were possibly related to the varlitinib treatment occurred. One death was related to disease progression (worsening of metastatic breast cancer), one death was related to acute kidney injury and one death was due to liver failure leading to multi-organ failure and sepsis. These deaths were reported to the appropriate regulatory authorities as “possibly related” to varlitinib because the immediate cause of the patient’s death could not be determined, and therefore, a relationship to varlitinib could not be excluded.

Serious adverse events observed in any of our clinical trials may adversely impact our ability to obtain regulatory approval for our product candidates. Further, if any of our approved products cause serious or unexpected side effects after receiving market approval, a number of potentially significant negative consequences could result, including:

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Any of these events could prevent us from achieving or maintaining market acceptance of the affected product candidate and could substantially increase the costs of commercializing our product candidates.

The regulatory approval processes of the U.S. FDA, CFDA and comparable foreign authorities are lengthy, time consuming and inherently unpredictable, and if we are ultimately unable to obtain regulatory approval for our product candidates, our business will be substantially harmed.

The time required to obtain approval by the U.S. FDA, CFDA and comparable foreign authorities is unpredictable but typically takes many years following the commencement of clinical trials and depends upon numerous factors, including the substantial discretion of the regulatory authorities. In addition, approval policies, regulations, or the type and amount of clinical data necessary to gain approval may change during the course of a product candidate’s clinical development and may vary among jurisdictions. For example, we cannot guarantee that our ongoing pivotal clinical trials of varlitinib in biliary tract cancer and gastric cancer will be sufficient to warrant accelerated approval or that our Phase 2 clinical trials of ASLAN003 in AML will be sufficient to allow subsequent development or that the U.S. FDA or comparable foreign regulatory authorities will not require additional or different clinical trials prior to subsequent development of ASLAN003 or that the required primary endpoints in subsequent pivotal trials or other clinical trials will be different than those in Phase 2 clinical trials.

Our product candidates could fail to receive regulatory approval for many reasons, including the following:

This lengthy approval process, as well as the unpredictability of future clinical trial results, may result in our failing to obtain regulatory approval to market our product candidates, which would harm our business, results of operations and prospects significantly.

In addition, even if we were to obtain approval, regulatory authorities may approve any of our product candidates for fewer or more limited indications than we request, may not approve the price we intend to charge for our

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products, may grant approval contingent on the performance of costly post-marketing clinical trials, or may approve a product candidate with a label that does not include the labeling claims necessary or desirable for the successful commercialization of that product candidate. Any of the foregoing scenarios could harm the commercial prospects for our product candidates.

We have not previously submitted an NDA, BLA or any similar drug approval filing to the U.S. FDA or any comparable foreign authority for any product candidate, and we cannot be certain that any of our product candidates will be successful in clinical trials or receive regulatory approval. Further, our product candidates may not receive regulatory approval even if they are successful in clinical trials. If we do not receive regulatory approvals for our product candidates, we may not be able to continue our operations. Even if we successfully obtain regulatory approvals to market one or more of our product candidates, our revenue will be dependent, to a significant extent, upon the size of the markets in the territories for which we gain regulatory approval. If the markets for patients or indications that we are targeting are not as significant as we estimate, we may not generate significant revenue from sales of such products, if approved.

Pharmaceutical companies in China are required to comply with extensive regulations and hold a number of permits and licenses to carry on their business. Our ability to obtain and maintain these regulatory approvals is uncertain, and future government regulation may place additional burdens on our efforts to commercialize our product candidates.

The pharmaceutical industry in China is subject to extensive government regulation and supervision. The regulatory framework addresses all aspects of operating in the pharmaceutical industry, including approval, registration, production, distribution, packaging, labelling, storage and shipment, advertising, licensing and certification requirements and procedures, periodic renewal and reassessment processes, registration of new drugs and environmental protection. In order to commercialize our product candidates and manufacture and distribute pharmaceutical products in China, we are required to:

If we are unable to obtain or renew such permits or any other permits or licenses required for our operations, will not be able to engage in the commercialization, manufacture and distribution of our product candidates and our business may be adversely affected.

The regulatory framework governing the pharmaceutical industry in China is subject to change and amendment from time to time. The Chinese government has introduced various reforms to the Chinese healthcare system in recent years and may continue to do so, with an overall objective to expand basic medical insurance coverage and improve the quality and reliability of healthcare services. The specific regulatory changes under the reform still remain uncertain. The implementing measures to be issued may not be sufficiently effective to achieve the stated goals, and as a result, we may not be able to benefit from such reform to the level we expect, if at all. Moreover, the reform could give rise to regulatory developments, such as more burdensome administrative procedures, which may have an adverse effect on our business and prospects.

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Even if we obtain regulatory approval for our product candidates, we will still face extensive regulatory requirements and our products may face future development and regulatory difficulties.

Even if we obtain regulatory approval in the United States, China or other markets, the U.S. FDA, CFDA or other regulatory authorities, as applicable, may still impose significant restrictions on the indicated uses or marketing of our product candidates, or impose ongoing requirements for potentially costly post-approval studies or post-market surveillance. Our product candidates, if approved, will also be subject to ongoing U.S. FDA, CFDA and/or other applicable regulatory requirements governing the labeling, packaging, storage, distribution, safety surveillance, advertising, promotion, record-keeping and reporting of safety and other post-market information. The holder of an approved NDA or BLA is obligated to monitor and report AEs and any failure of a product to meet the specifications in the NDA or BLA, as applicable. The holder of an approved NDA or BLA must also submit new or supplemental applications and obtain U.S. FDA approval for certain changes to the approved product, product labeling or manufacturing process. Advertising and promotional materials must comply with U.S. FDA rules and are subject to U.S. FDA review, in addition to other potentially applicable federal and state laws.

In addition, manufacturers of drug products and their facilities are subject to payment of user fees and continual review and periodic inspections by the U.S. FDA, CFDA and other regulatory authorities for compliance with current good manufacturing practices, or cGMP, and adherence to commitments made in the NDA. If we or a regulatory agency discovers previously unknown problems with a product, such as AEs of unanticipated severity or frequency, or problems with the facility where the product is manufactured, a regulatory agency may impose restrictions relative to that product or the manufacturing facility, including requiring recall or withdrawal of the product from the market or suspension of manufacturing.

If we fail to comply with applicable regulatory requirements following approval of a product candidate, a regulatory agency may:

In particular, we may seek accelerated approval from the U.S. FDA for our product candidates which will likely require a further confirmatory trial. If this confirmatory trial is not successful, we will be required to withdraw our product candidate from the U.S. market and potentially other markets. For instance, we intend to seek accelerated approval for varlitinib in second-line biliary tract cancer.

Any government investigation of alleged violations of law could require us to expend significant time and resources in response and could generate negative publicity. The occurrence of any event or penalty described above may inhibit our ability to commercialize our products and generate revenue.

In addition, if any of our product candidates are approved and we are found to have improperly promoted off-label uses of those products, we may become subject to significant liability. The U.S. FDA and other regulatory agencies strictly regulate the promotional claims that may be made about prescription products, such as our product candidates, if approved. In particular, a product may not be promoted for uses that are not approved by the U.S. FDA or such other regulatory agencies as reflected in the product’s approved labeling. For example, if we receive marketing approval for varlitinib as a treatment for gastric cancer or biliary tract cancer,

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physicians may nevertheless use our product for their patients in a manner that is inconsistent with the approved label. If we are found to have promoted such off-label uses, we may become subject to significant liability, which would materially adversely affect our business and financial condition.

Even if we obtain U.S. FDA approval for our product candidates in the United States, we may never obtain approval to commercialize our product candidates outside of the United States, which would limit our ability to realize their full market potential.

In order to market any products outside of the United States, we must establish and comply with numerous and varying regulatory requirements of other countries regarding safety and efficacy. Clinical trials conducted in one country may not be accepted by regulatory authorities in other countries, and regulatory approval in one country does not mean that regulatory approval will be obtained in any other country. Approval processes vary among countries and can involve additional product testing and validation and additional administrative review periods. Seeking foreign regulatory approval could result in difficulties and costs for us and require additional non-clinical studies or clinical trials which could be costly and time consuming. Regulatory requirements can vary widely from country to country and could delay or prevent the introduction of our products in those countries. We do not have any product candidates approved for sale in any jurisdiction, including international markets, and we do not have experience in obtaining regulatory approval in international markets. If we fail to comply with regulatory requirements in international markets or to obtain and maintain required approvals, or if regulatory approvals in international markets are delayed, our target market will be reduced and our ability to realize the full market potential of our products will be harmed.

If we fail to develop, acquire or in-license other product candidates or products, our business and prospects will be limited.

Our long-term growth strategy is to develop, acquire or in-license and commercialize a portfolio of product candidates in addition to varlitinib and our other existing product candidates. Identifying, selecting and acquiring or licensing promising product candidates requires substantial technical, financial and human resources expertise. Efforts to do so may not result in the actual development, acquisition or license of a particular product candidate, potentially resulting in a diversion of our management’s time and the expenditure of our resources with no resulting benefit. If we are unable to add additional product candidates to our pipeline, our long-term business and prospects will be limited.

We rely on third parties to conduct our preclinical studies and clinical trials. If these third parties do not successfully carry out their contractual duties or meet expected deadlines, we may not be able to obtain regulatory approval for or commercialize our product candidates and our business could be substantially harmed.

We have relied upon and plan to continue to rely upon third-party CROs to conduct our preclinical studies and clinical trials, including investigator-initiated studies sponsored by the investigator’s institution, and control only certain aspects of their activities. Nevertheless, we are responsible for ensuring that each of our trials is conducted in accordance with the applicable protocol, legal, regulatory and scientific standards and our reliance on the CROs does not relieve us of our regulatory responsibilities. We and our CROs are required to comply with U.S. FDA laws and regulations regarding current good clinical practice, or cGCP, which are also required by the Competent Authorities of the Member States of the European Economic Area and comparable foreign regulatory authorities in the form of International Conference on Harmonization, or ICH, guidelines for all of our products in clinical development. Regulatory authorities enforce cGCP through periodic inspections of trial sponsors, principal investigators and trial sites. If we or any of our CROs fail to comply with applicable cGCP, the clinical data generated in our clinical trials may be deemed unreliable and the U.S. FDA or comparable foreign regulatory authorities may require us to perform additional clinical trials before approving our marketing applications. We cannot assure you that upon inspection by a given regulatory authority, such regulatory authority will determine that any of our clinical trials comply with cGCP regulations. In addition, our clinical

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trials must be conducted with product produced under cGMP regulations. While we have agreements governing activities of our CROs, we have limited influence over their actual performance. In addition, portions of the clinical trials for our product candidates are expected to be conducted at various locations great distances from where our principal operations are located in Singapore, which will make it more difficult for us to monitor CROs and perform visits of our clinical trial sites and will force us to rely heavily on CROs to ensure the proper and timely conduct of our clinical trials and compliance with applicable regulations, including cGCP. Failure to comply with applicable regulations in the conduct of the clinical trials for our product candidates may require us to repeat clinical trials, which would delay the regulatory approval process.

Some of our CROs have an ability to terminate their respective agreements with us if, among other reasons, it can be reasonably demonstrated that the safety of the subjects participating in our clinical trials warrants such termination, if we make a general assignment for the benefit of our creditors or if we are liquidated. If any 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. In addition, our CROs are not our employees, and except for remedies available to us under our agreements with such CROs, we cannot control whether or not they devote sufficient time and resources to our preclinical and clinical programs. If CROs do not successfully carry out their contractual duties or obligations or meet expected deadlines, if they need to be replaced or if the quality or accuracy of the clinical data they obtain is compromised due to the failure to adhere to our clinical protocols, regulatory requirements or for other reasons, our clinical trials may be extended, delayed or terminated and we may not be able to obtain regulatory approval for or successfully commercialize our product candidates. Consequently, our results of operations and the commercial prospects for our product candidates would be harmed, our costs could increase substantially and our ability to generate revenue could be delayed significantly.

Switching or adding additional CROs involves additional cost and requires management time and focus. In addition, there is a natural transition period when a new CRO commences work. As a result, delays occur, which can materially impact our ability to meet our desired clinical development timelines. Though we carefully manage our relationships with our CROs, there can be no assurance 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.

Risks Related to Our Business Operations and Industry

Our future success depends on our ability to retain key executives and to attract, retain and motivate qualified personnel.

We are highly dependent on the principal members of our executive team listed under “Management” located elsewhere in this prospectus, the loss of whose services may adversely impact the achievement of our objectives. While we have entered into employment agreements with each of our executive officers, any of them could leave our employment at any time, subject to any applicable notice requirements. Recruiting and retaining other qualified employees for our business, including scientific and technical personnel, will also be critical to our success. Competition for skilled personnel is intense and the turnover rate can be high. We may not be able to attract and retain personnel on acceptable terms given the competition among numerous pharmaceutical companies for individuals with similar skill sets. In addition, failure to succeed in clinical studies may make it more challenging to recruit and retain qualified personnel. The inability to recruit or loss of the services of any executive or key employee might impede the progress of our development and commercialization objectives.

We will need to expand our organization, and we may experience difficulties in managing this growth, which could disrupt our operations.

As of December 31, 2017, we had 47 full-time employees. As our company matures, we expect to expand our employee base to increase our managerial, scientific, clinical, operational, financial and other resources, to add a sales and marketing function and to hire more consultants and contractors. Future growth would impose

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significant additional responsibilities on our management, including the need to identify, recruit, maintain, motivate and integrate additional employees, consultants and contractors. Also, our management may need to divert a disproportionate amount of its attention away from our day-to-day activities and devote a substantial amount of time to managing these growth activities. We may not be able to effectively manage the expansion of our operations, which may result in weaknesses in our infrastructure, give rise to operational mistakes, loss of business opportunities, loss of employees and reduced productivity among remaining employees. Future growth could require significant capital expenditures and may divert financial resources from other projects, such as the development of our existing or future product candidates. If our management is unable to effectively manage our growth, our expenses may increase more than expected, our ability to generate and grow revenue could be reduced, and we may not be able to implement our business strategy. Our future financial performance and our ability to commercialize our product candidates, if approved, and compete effectively will depend, in part, on our ability to effectively manage any future growth.

We face potential product liability, and, if successful claims are brought against us, we may incur substantial liability.

The use of our product candidates in clinical trials and the sale of any products for which we obtain marketing approval exposes us to the risk of product liability claims. Product liability claims might be brought against us by consumers, healthcare providers, pharmaceutical companies or others selling or otherwise coming into contact with our products and product candidates. If we cannot successfully defend against product liability claims, we could incur substantial liability and costs. In addition, regardless of merit or eventual outcome, product liability claims may result in:

Our current clinical trial liability insurance coverage may not be sufficient to reimburse us for any expenses or losses we may suffer. Moreover, insurance coverage is becoming increasingly expensive and in the future we may not be able to maintain insurance coverage at a reasonable cost or in sufficient amounts to protect us against losses due to liability. If and when we obtain marketing approval for our product candidates, we intend to expand our insurance coverage to include the sale of commercial products; however, we may be unable to obtain product liability insurance on commercially reasonable terms or in adequate amounts. On occasion, large judgments have been awarded in class action lawsuits based on drugs that had unanticipated adverse effects. A successful product liability claim or series of claims brought against us could cause the price of our ADSs or ordinary shares to decline and, if judgments exceed our insurance coverage, could adversely affect our results of operations and business.

Our internal computer systems, or those of our CROs or other contractors or consultants, may fail or suffer security breaches, which could result in a material disruption of our operations.

Despite the implementation of security measures, our internal computer systems and those of our CROs and other contractors and consultants are vulnerable to damage from computer viruses, unauthorized access, natural disasters, terrorism, war and telecommunication and electrical failures. Such events could cause interruptions of our operations. For instance, the loss of preclinical study or clinical trial data involving our product candidates

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could result in delays in our development and regulatory filing efforts and significantly increase our costs. In addition, theft or other exposure of data may interfere with our ability to protect our intellectual property, trade secrets, and other information critical to our operations. We can provide no assurances that certain sensitive and proprietary information relating to one or more of our product candidates has not been, or will not in the future be, compromised. There can be no assurances we will not experience unauthorized intrusions into our computer systems, or those of our CROs and other contractors and consultants, that we will successfully detect future unauthorized intrusions in a timely manner, or that future unauthorized intrusions will not result in material adverse effects on our financial condition, reputation, or business prospects.

Certain data breaches must also be reported to affected individuals and the government, and in some cases to the media, under provisions of the U.S. Health Insurance Portability and Accountability Act of 1996, or HIPAA, as amended by the Health Information Technology for Economic and Clinical Health Act, or HITECH, other U.S. federal and state law, and requirements of non-U.S. jurisdictions, including the European Union Data Protection Directive, and financial penalties may also apply.

Our insurance policies may not be adequate to compensate us for the potential losses arising from breaches, failures or disruptions of our infrastructure, catastrophic events and disasters or otherwise. In addition, such insurance may not be available to us in the future on economically reasonable terms, or at all. Further, our insurance may not cover all claims made against us and defending a suit, regardless of its merit, could be costly and divert management’s attention.

Furthermore, the loss of clinical trial data from completed or future clinical trials could result in delays in our regulatory approval efforts and significantly increase our costs to recover or reproduce the data. Likewise, we rely on other third parties for the manufacture of our product candidates and to conduct clinical trials, and similar events relating to their computer systems could also have a material adverse effect on our business.

In addition to in-licensing or acquiring product candidates, we may engage in future business acquisitions that could disrupt our business, cause dilution to our ADS holders and harm our financial condition and operating results.

While we currently have no specific plans to acquire any other businesses, we have, from time to time, evaluated acquisition opportunities and may, in the future, make acquisitions of, or investments in, companies that we believe have products or capabilities that are a strategic or commercial fit with our current product candidates and business or otherwise offer opportunities for our company. In connection with these acquisitions or investments, we may:

We also may be unable to find suitable acquisition candidates and we may not be able to complete acquisitions on favorable terms, if at all. If we do complete an acquisition, we cannot assure you that it will ultimately strengthen our competitive position or that it will not be viewed negatively by customers, financial markets or investors. Further, future acquisitions could also pose numerous additional risks to our operations, including:

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We may not be able to complete one or more acquisitions or effectively integrate the operations, products or personnel gained through any such acquisition without a material adverse effect on our business, financial condition and results of operations.

Our Asia development platform is unproven and may not result in the competitive advantages we anticipate.

We have built a development platform centered in Asia that is designed to enable us to accelerate the development of drugs which target Asia prevalent diseases and which we believe can generate data suitable for submission to regulators in the United States, Europe, China and Japan. Although data collected in Asia from the varlitinib biliary tract cancer clinical trial as well as other varlitinib clinical data have been submitted to a number of regulatory authorities, including the U.S. FDA, the CFDA, the Pharmaceutical and Medical Devices Agency, or PMDA, the Health Sciences Authority in Singapore, the Taiwan Food and Drug Administration and the Ministry of Food and Drug Safety in South Korea, and after reviewing the data these health authorities have each agreed to include patients from their respective countries in the varlitinib biliary tract cancer clinical trials, we cannot guarantee this result will hold true in the future. Regulatory authorities could potentially reject Asia data if they believe that the Asian disease population is substantially different from the disease population in their particular country. However, in the case of the U.S. FDA, we have mutually agreed that 20% of the patients in the varlitinib pivotal study will be from the United States and that this number of U.S. patients is sufficient to support conditional approval. Furthermore, while we have shown in certain cases that the pharmacokinetics in Asian and Caucasian patients are similar, we cannot guarantee that this will hold true more generally or in the future, or with respect to other ethnicities. While we believe our platform in Asia offers us an opportunity to accelerate the development of novel therapies in diseases where either the diseases are more prevalent or the availability of suitable patients in clinical trials is greater, an Asia-focused development platform is a relatively novel approach to drug development and has not yet resulted in a proven track record of accelerated development or regulatory approval.

Furthermore, drug development focused in Asia may be subject to a number of risks and uncertainties. We cannot assure you that governments of Asian countries will not enact regulations or incentives that favor local pharmaceutical companies over foreign-owned pharmaceutical companies. Any developments in Asia that make clinical development costlier or more time-consuming could delay our development timelines and materially harm our business and results of operations.

Our operations across Asia could be subject to natural disasters, health epidemics and other business disruptions, which could have a material adverse effect on our business, results of operation and financial condition.

Our operations, and in particular our clinical trials, are being conducted across areas of Asia that may be prone to natural disasters, such as earthquakes, cyclones, monsoons and floods, which could cause interruptions to our operations. In addition, the areas in which our clinical trials could be adversely affected by the outbreak of influenza A (H1N1), avian influenza (H7N9), severe acute respiratory syndrome (SARS) or other pandemics. Any occurrence of these natural disasters or pandemic diseases or other adverse public health developments in the areas in which we operate our clinical trials could disrupt or delay our business operations or clinical development, which could materially adversely affect our business.

Our business is subject to economic, political, regulatory and other risks associated with international operations.

As a company based in Singapore with an Asia based development platform, our business is subject to risks associated with conducting business outside of the United States. Many of our suppliers and collaborative and

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clinical trial relationships are located outside the United States. Accordingly, our future results could be harmed by a variety of factors, including:

More specifically, the economy in Asia differs from most developed markets in many respects, including the level of government involvement, level of development, growth rate, control of foreign exchange, government policy on public order and allocation of resources. In some of the Asian markets, governments continue to play a significant role in regulating industry development by imposing industrial policies. Moreover, some local governments also exercise significant control over the economic growth and public order in their respective jurisdictions through allocating resources, controlling payment of foreign currency-denominated obligations, setting monetary policies, and providing preferential treatment to particular industries or companies. In addition, some Asian markets have experienced, and may in the future experience, political instability, including strikes, demonstrations, protests, marches, coups d’état, guerilla activity or other types of civil disorder. These instabilities and any adverse changes in the political environment could increase our costs, increase our exposure to legal and business risks, or disrupt our clinical operations.

Risks Related to Our Intellectual Property

If we are unable to obtain or protect intellectual property rights related to our current product candidates or any future product candidates which we may develop, we may not be able to compete effectively in our market.

We rely upon a combination of patents, trade secret protection, confidentiality agreements and proprietary know-how, and intend to seek marketing exclusivity for any approved product, in order to protect the intellectual property related to product candidates. The strength of patents in the biotechnology and pharmaceutical field

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involves complex legal and scientific questions and can be uncertain. The patent applications that we own or in-license may fail to result in issued patents with claims that cover our product candidates in the United States or in other foreign countries for a number of reasons, including because of a finding of lack of novelty or that the claimed inventions are already in the public domain. If this were to occur, early generic competition could be expected against our product candidates. Even if patents do successfully issue, third parties may challenge their validity, enforceability or scope, which may result in such patents being invalidated or deemed as not infringing. Also, a third party may challenge our ownership of patents and patent applications assigned to us, or may challenge our exclusive rights to patents and patent applications that we license from third parties. Furthermore, even if they are unchallenged, our patents and patent applications may not adequately protect our intellectual property or prevent others from designing around our claims. If the patent applications we hold with respect to our other product candidates fail to issue or if their breadth or strength of protection is threatened, it could dissuade companies from collaborating with us to develop them, and threaten our ability to commercialize any resulting products. We cannot offer any assurances about which, if any, applications will issue as patents or whether any issued patents will be found not invalid and not unenforceable or will go unthreatened by third parties. Further, if we encounter delays in regulatory approvals, the period of time during which we could market our product candidates under patent protection could be reduced. Furthermore, patent applications by third parties can result in an interference proceeding in the United States being invoked by a third party or instituted by us to determine who was the first to invent any of the subject matter covered by the patent claims of our applications or patents.

In addition to the protection afforded by patents, we rely on trade secret protection and confidentiality agreements to protect proprietary know-how that is not patentable, processes for which patents are difficult to enforce and any other elements of our drug development process that involve proprietary know-how, information or technology that is not covered by patents. Although we generally require all of our employees to assign their inventions to us, and all of our employees, consultants, advisors and any third parties who have access to our proprietary know-how, information or technology to enter into confidentiality agreements, we cannot provide any assurances that all such agreements have been duly executed or that our trade secrets and other confidential proprietary information will not be disclosed or that competitors will not otherwise gain access to our trade secrets or independently develop substantially equivalent information and techniques. If we are unable to prevent material disclosure of the non-patented intellectual property related to our technologies to third parties, and there is no guarantee that we will have any such enforceable trade secret protection, we may not be able to establish or maintain a competitive advantage in our market, which could materially adversely affect our business, results of operations and financial condition.

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

Filing, prosecuting, and defending patents on product candidates in all countries throughout the world would be prohibitively expensive, and the laws of foreign countries may not protect our rights to the same extent as the laws of the United States. Consequently, we may not be able to prevent third parties from practicing our inventions in all countries outside the United States, or from selling or importing products made using our inventions in and into the United States or other jurisdictions. Competitors may use our technologies in jurisdictions where we have not obtained patent protection to develop their own products and, further, may export otherwise infringing products to territories where we have patent protection but enforcement is not as strong as that in the United States. These products may compete with our products, and our patents or other intellectual property rights may not be effective or sufficient to prevent them from competing.

Many companies have encountered significant problems in protecting and defending intellectual property rights in foreign jurisdictions. The legal systems of certain countries, particularly certain developing countries, do not favor the enforcement of patents, trade secrets, and other intellectual property protection, which could make it difficult for us to stop the infringement of our patents or marketing of competing products in violation of our intellectual property and proprietary rights generally. Proceedings to enforce our intellectual property and proprietary rights in foreign jurisdictions could result in substantial costs and divert our efforts and attention from

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other aspects of our business, could put our patents at risk of being invalidated or interpreted narrowly, could put our patent applications at risk of not issuing, and could provoke third parties to assert claims against us. We may not prevail in any lawsuits that we initiate, and the damages or other remedies awarded, if any, may not be commercially meaningful. Accordingly, our efforts to enforce our intellectual property and proprietary rights around the world may be inadequate to obtain a significant commercial advantage from the intellectual property that we develop or license.

Several countries have compulsory licensing laws under which, in certain circumstances, a patent owner may be compelled to grant licenses to third parties. In addition, many countries limit the enforceability of patents against government agencies or government contractors. In these countries, the patent owner may have limited remedies, which could materially diminish the value of such patent. If we or any of our licensors is forced to grant a license to third parties with respect to any patents relevant to our business, our competitive position may be impaired, and our business, financial condition, results of operations, and prospects may be adversely affected.

In China, the validity, enforceability and scope of protection available under the relevant intellectual property laws are uncertain and still evolving. Implementation and enforcement of Chinese intellectual property-related laws have historically been inconsistent. Accordingly, intellectual property and confidentiality legal regimes in China may not afford protection to the same extent as in the United States or other countries. Policing unauthorized use of proprietary technology is difficult and expensive, and we may need to resort to litigation to enforce or defend patents issued to us or to determine the enforceability, scope and validity of our proprietary rights or those of others. The experience and capabilities of Chinese courts in handling intellectual property litigation varies, and outcomes are unpredictable. Further, such litigation may require a significant expenditure of cash and may divert management’s attention from our operations, which could harm our business, financial condition and results of operations. An adverse determination in any such litigation could materially impair our intellectual property rights and may harm our business, prospects and reputation in China.

If we fail to comply with our obligations in the agreements under which we license rights to technology from third parties, or if the license agreements are terminated for other reasons, we could lose license rights that are important to our business.

We are a party to a number of technology licenses that are important to our business and expect to enter into additional licenses in the future. For example, our rights to varlitinib are the subject of an exclusive license agreement with Array. If we fail to comply with our obligations under our agreement with Array (including, among other things, if we fail to use commercially reasonable efforts to develop and commercialize varlitinib) or our other license agreements, or we are subject to insolvency or liquidation, the licensor may have the right to terminate the license. In addition, under our agreement with Array, in the event of a change of control, we may be required to make additional payment to Array if the change of control meets specified conditions. In the event that any of our important technology licenses were to be terminated by the licensor, we would likely cease further development of the related program. See “Business—License and Collaboration Agreements” for a description of our license agreements, which includes a description of the termination provisions of these agreements.

We are generally also subject to all of the same risks with respect to protection of intellectual property that we license, as we are for intellectual property that we own, which are described elsewhere under “Risks Related to Our Intellectual Property.” If we or our licensors fail to adequately protect this intellectual property, our ability to commercialize products could suffer.

Third-party claims of intellectual property infringement may prevent or delay our development and commercialization efforts.

Our commercial success depends in part on our avoiding infringement of the patents and proprietary rights of third parties. There is a substantial amount of litigation, both within and outside the United States, involving

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patent and other intellectual property rights in the biotechnology and pharmaceutical industries, including patent infringement lawsuits, interferences, oppositions and inter party reexamination proceedings before the U.S. Patent and Trademark Office, or the USPTO. Numerous U.S. and foreign issued patents and pending patent applications, which are owned by third parties, exist in the fields in which we and our collaborators are developing product candidates. As the biotechnology and pharmaceutical industries expand and more patents are issued, the risk increases that our product candidates may be subject to claims of infringement of the patent rights of third parties.

Third parties may assert that we are employing their proprietary technology without authorization. There may be third-party patents or patent applications with claims to materials, formulations, methods of manufacture or methods for treatment related to the use or manufacture of our product candidates. Because patent applications can take many years to issue, there may be currently pending patent applications which may later result in issued patents that our product candidates may infringe. In addition, third parties may obtain patents in the future and claim that use of our technologies infringes upon these patents. If any third-party patents were held by a court of competent jurisdiction to cover the manufacturing process of any of our product candidates, any drug substance formed during the manufacturing process or any final product itself, the holders of any such patents may be able to block our ability to commercialize such product candidate unless we obtain a license under the applicable patents, or until such patents are invalidated or expire. Similarly, if any third-party patent were held by a court of competent jurisdiction to cover aspects of our formulations or methods of use, the holders of any such patent may be able to block our ability to develop and commercialize the applicable product candidate formulation or use unless we obtain a license or until such patent expires. In either case, such a license may not be available on commercially reasonable terms or at all.

Parties making claims against us may request and/or obtain injunctive or other equitable relief, which could effectively block our ability to further develop and commercialize one or more of our product candidates. Defense of these claims, regardless of their merit, would involve substantial litigation expense and would be a substantial diversion of employee resources from our business. In the event of a successful claim of infringement against us, we may have to pay substantial damages, including treble damages and attorneys’ fees for willful infringement, obtain one or more licenses from third parties, pay royalties or redesign our infringing products or manufacturing processes, which may be impossible or require substantial time and monetary expenditure. We cannot predict whether any such license would be available at all or whether it would be available on commercially reasonable terms. Furthermore, even in the absence of litigation, we may need to obtain licenses from third parties to advance our research, manufacture clinical trial supplies or allow commercialization of our product candidates. We may fail to obtain any of these licenses at a reasonable cost or on reasonable terms, if at all. In that event, we would be unable to further develop and commercialize one or more of our product candidates, which could harm our business significantly. We cannot provide any assurances that third-party patents do not exist which might be enforced against our products, resulting in either an injunction prohibiting our sales, or, with respect to our sales, an obligation on our part to pay royalties and/or other forms of compensation to third parties.

We may be involved in lawsuits to protect or enforce our patents or the patents of our licensors, which could be expensive, time consuming and unsuccessful.

Competitors may infringe our patents or the patents of our licensors. To counter infringement or unauthorized use, we may be required to file infringement claims, which can be expensive and time-consuming. In addition, in an infringement proceeding, a court may decide that a patent of ours or our licensors is not valid or is unenforceable, or may refuse to stop the other party from using the technology at issue on the grounds that our patents do not cover the technology in question. An adverse result in any litigation or defense proceedings could put one or more of our patents at risk of being invalidated or interpreted narrowly and could put our patent applications at risk of not issuing.

Interference proceedings provoked by third parties or brought by us may be necessary to determine the priority of inventions with respect to our patents or patent applications or those of our collaborators or licensors. An

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unfavorable outcome could require us to cease using the related technology or to attempt to license rights to it from the prevailing party. Our business could be harmed if the prevailing party does not offer us a license on commercially reasonable terms. Our defense of litigation or interference proceedings may fail and, even if successful, may result in substantial costs and distract our management and other employees. We may not be able to prevent, alone or with our licensors, misappropriation of our intellectual property rights, particularly in countries where the laws may not protect those rights as fully as in the United States.

Furthermore, because of the substantial amount of discovery required in connection with intellectual property litigation, there is a risk that some of our confidential information could be compromised by disclosure during this type of litigation. There could also be public announcements of the results of hearings, motions or other interim proceedings or developments. If securities analysts or investors perceive these results to be negative, it could have a material adverse effect on the price of our ADSs.

Obtaining and maintaining our patent protection depends on compliance with various procedural, document submission, 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 lifetime of the patent. The USPTO and various foreign governmental patent agencies require compliance with a number of procedural, documentary, fee payment and other similar provisions during the patent application process. While an inadvertent lapse can in 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 non-compliance can (i) result in abandonment or lapse of, or (ii) otherwise affect the patentability 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 a patent 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 submit formal documents. If we or our licensors that control the prosecution and maintenance of our licensed patents fail to maintain the patents and patent applications covering our product candidates, our competitors might be able to enter the market, which would have a material adverse effect on our business.

In addition, as licensees we may not be responsible for or have control over the prosecution or enforceability of our licensed patents. In such cases, we have to rely on the licensor to comply with the requisite obligations of the patent offices, including the duty of disclosure, filing assignments, etc. We cannot guarantee that all of these duties have been or will be complied with. As licensees, we may not be in a position to assess if these duties have been complied with or have the ability to complete these duties on behalf of the licensor. Failure to comply with such duties may affect the enforceability of the patent rights.

We may be subject to claims that our employees, consultants or independent contractors have wrongfully used or disclosed confidential information of third parties.

We employ individuals who were previously employed at other biotechnology or pharmaceutical companies. We may be subject to claims that we or our employees, consultants or independent contractors have inadvertently or otherwise used or disclosed confidential information of our employees’ former employers or other third parties. We may also be subject to claims that former employers or other third parties have an ownership interest in our patents. Litigation may be necessary to defend against these claims. There is no guarantee of success in defending these claims, and if we are successful, litigation could result in substantial cost and be a distraction to our management and other employees.

Although we have obtained orphan drug designation for varlitinib in gastric cancer and cholangiocarcinoma, a form of biliary tract cancer, in the United States, we may not be able to obtain or maintain the benefits associated with orphan drug status, including market exclusivity.

Regulatory authorities in some jurisdictions, including the United States and the European Union, may designate drugs for relatively small patient populations as orphan drugs. Under the Orphan Drug Act, the U.S. FDA may

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designate a drug as an orphan drug if it is intended to treat a rare disease or condition, which is generally defined as a patient population of fewer than 200,000 individuals annually in the United States. We have obtained orphan drug designation for varlitinib in gastric cancer and cholangiocarcinoma from the U.S. FDA, as well as for varlitinib in biliary tract cancer from the Ministry of Food and Drug Safety in South Korea. 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 may be entitled to a period of marketing exclusivity, which precludes the U.S. FDA from approving another marketing application for the same molecule for the same indication for that time period. We can provide no assurance that another drug will not receive marketing approval prior to our product candidates. The applicable period is seven years in the United States and ten years in Japan and the European Union. The exclusivity period in the European Union 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 so that market exclusivity is no longer justified. Orphan drug exclusivity may be lost if the U.S. FDA determines that the request for designation was materially defective or if the manufacturer is unable to assure sufficient quantity of the drug to meet the needs of patients with the rare disease or condition. In addition, even after a drug is granted orphan exclusivity and approved, the U.S. FDA can subsequently approve another drug for the same condition before the expiration of the seven year exclusivity period if the U.S. 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.

If our trademarks and tradenames are not adequately protected, then we may not be able to build name recognition in our markets and our business may be adversely affected.

We have registered or applied to register certain trademarks to protect our company name and plan to apply to register trademarks to cover product names in the future once our product candidates are closer to commercialization. We cannot assure you that our trademark applications will be approved or that we will seek registered trademark protection for each of our product names in each jurisdiction in which we operate. During trademark registration proceedings, we may receive rejections. Although we are given an opportunity to respond to those rejections, we may be unable to overcome such rejections. In addition, in proceedings before the USPTO and in proceedings before comparable agencies in many foreign jurisdictions, third parties are given an opportunity to oppose pending trademark applications and to seek to cancel registered trademarks. Opposition or cancellation proceedings may be filed against our trademarks, and our trademarks may not survive such proceedings. In the event that our trademarks are successfully challenged, we could be forced to rebrand our products, which could result in loss of brand recognition and could require us to devote resources toward advertising and marketing new brands. Further, we cannot assure you that competitors will not infringe our trademarks or that we will have adequate resources to enforce our trademarks.

Risks Related to Commercialization of Our Product Candidates

Our commercial success depends upon attaining significant market acceptance of our product candidates, if approved, among physicians, healthcare payors, patients and the medical community.

Even if we obtain regulatory approval for our product candidates, the product may not gain market acceptance among physicians, healthcare payors, patients and the medical community, which is critical to commercial success. Market acceptance of any product candidate for which we receive approval depends on a number of factors, including:

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If our product candidates are approved but fail to achieve an adequate level of acceptance by physicians, healthcare payors, patients and the medical community, we will not be able to generate significant revenue, and we may not become or remain profitable. In addition, even if any of our product candidates gain acceptance, the markets for the treatment of patients with our target indications may not be as significant as we estimate.

Our organization has no prior sales and marketing experience and resources.

We plan to start building a targeted commercial organization in 2018 in anticipation of the potential regulatory approval of varlitinib for biliary tract cancer and gastric cancer. We have never, as an organization, commercialized a product and there is no guarantee that we will be able to do so successfully. We will need to establish a commercial team and hire sales forces in the geographies where we are permitted and intend to market our drugs. We will also need to develop a marketing team and strategy in order to successfully market and sell our product candidates, which will require significant time and resources and the development of our ability to market and sell our product and generate revenues from our product candidates may be delayed or limited. We cannot assure you that our sales efforts will be effective or produce the results we expect. We will be competing with other pharmaceutical and biotechnology companies to recruit, hire, train and retain marketing and sales personnel. Further, we may face difficulties or delays in obtaining and maintaining the required licenses and permits to sell our product candidates in individual states and jurisdictions. If our commercialization of varlitinib or our other product candidates is unsuccessful or perceived as disappointing, the price of our ADSs could decline significantly and the long-term success of the product and our company could be harmed.

We may also seek to establish collaborations with pharmaceutical companies to maximize the potential of our products in other markets, and we may not be successful in establishing development and commercialization collaborations which could adversely affect, and potentially prohibit, our ability to develop our product candidates.

If our planned targeted commercial organization in the United States and selected Asian markets is not as successful as we anticipate, we may be unable to generate any revenue.

Although we intend to start building a targeted commercial organization in the future, we currently have no such organization or capabilities, and the cost of establishing and maintaining such an organization may exceed the cost-effectiveness of doing so. In order to market any products that may be approved, we must build sales, marketing, managerial and other non-technical capabilities or make arrangements with third parties to perform these services. We may enter into strategic partnerships with third parties to commercialize our product candidates.

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Part of our business strategy is to establish collaborative relationships to commercialize and fund development and approval of certain of our product candidates, in particular ASLAN004. We may not succeed in establishing and maintaining collaborative relationships, which may significantly limit our ability to develop and commercialize products, including ASLAN004, for which we pursue this commercialization strategy.

We will need to establish and maintain successful collaborative relationships to obtain sales, marketing and distribution capabilities for the product candidates we do not intend to commercialize ourselves, in particular ASLAN004. The process of establishing and maintaining collaborative relationships is difficult, time-consuming and involves significant uncertainty, including:

If any collaborator fails to fulfill its responsibilities in a timely manner, or at all, any clinical development, manufacturing or commercialization efforts pursuant to that collaboration could be delayed or terminated, or it may be necessary for us to assume responsibility for expenses or activities that would otherwise have been the responsibility of our collaborator. If we are unable to establish and maintain collaborative relationships on acceptable terms or to successfully and timely transition terminated collaborative agreements, we may have to delay or discontinue further development of one or more of our product candidates, undertake development and commercialization activities at our own expense or find alternative sources of capital.

Attempting to secure additional financing for a product candidate may also lead to the risks discussed under the risk factor titled “We will need to obtain substantial amounts of financing for our operations, and if we fail to obtain additional financing, we may be forced to delay, reduce or eliminate our product development programs or commercialization efforts” described above.

We rely completely on third parties to manufacture our preclinical and clinical drug supplies and we intend to rely on third parties to produce commercial supplies of any approved product candidate.

If we were to experience an unexpected loss of supply of our product candidates for any reason, whether as a result of manufacturing, supply or storage issues or otherwise, we could experience delays, disruptions, suspensions or terminations of, or be required to restart or repeat, clinical trials. We do not currently have nor do we plan to acquire the infrastructure or capability internally to manufacture our preclinical and clinical drug supplies and we lack the resources and the capability to manufacture any of our product candidates on a clinical or commercial scale. The facilities used by our contract manufacturers or other third-party manufacturers to manufacture our product candidates must be approved by the U.S. FDA, CFDA or other regulators pursuant to inspections. While we work closely with our third-party manufacturers on the manufacturing process for our product candidates, including quality audits, we generally do not control the implementation of the manufacturing process of, and are completely dependent on, our contract manufacturers or other third-party manufacturers for compliance with cGMP regulatory requirements and for manufacture of both active drug substances and finished drug products. If our contract manufacturers or other third-party manufacturers cannot successfully manufacture material that conforms to applicable specifications and the strict regulatory

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requirements of the U.S. FDA, CFDA or other regulators, they will not be able to secure and/or maintain regulatory approval for their manufacturing facilities. In addition, we have no control over the ability of our contract manufacturers or other third-party manufacturers to maintain adequate quality control, quality assurance and qualified personnel. If the U.S. FDA, CFDA or other regulators do not approve these facilities for the manufacture of our product candidates or if they withdraw any such approval in the future, we may need to find alternative manufacturing facilities, which could take several years and would significantly impact our ability to develop, obtain regulatory approval for or market our product candidates, if approved.

We rely on our manufacturers to purchase from third-party suppliers the materials necessary to produce our product candidates for our clinical trials. There are a limited number of suppliers for raw materials that we use to manufacture our product candidates and there may be a need to assess alternate suppliers to prevent a possible disruption of the manufacture of the materials necessary to produce our product candidates for our clinical trials, and if approved, for commercial sale. We do not have any control over the process or timing of the acquisition of these raw materials by our manufacturers. Although we generally do not begin a clinical trial unless we believe we have a sufficient supply of a product candidate to complete the clinical trial, any significant delay in the supply of a product candidate, or the raw material components thereof, for an ongoing clinical trial due to the need to replace a contract manufacturer or other third-party manufacturer could considerably delay completion of our clinical trials, product testing and potential regulatory approval of our product candidates. If our manufacturers or we are unable to purchase these raw materials after regulatory approval has been obtained for our product candidates, the commercial launch of our product candidates would be delayed or there would be a shortage in supply, which would impair our ability to generate revenue from the sale of our product candidates.

We expect to continue to depend on contract manufacturers or other third-party manufacturers for the foreseeable future, and our requirements for and dependence upon these third-party manufacturers will increase when and if one or more of our product candidates is approved and commercialized. Other than Sterling Pharma Solutions, we have not entered into long-term commercial supply agreements with our current contract manufacturers or with any alternate fill/finish suppliers. Although we intend to do so prior to any commercial launch of our product candidates, if approved by the U.S. FDA, in order to ensure that we maintain adequate supplies of finished drug product, we may be unable to enter into such an agreement or do so on commercially reasonable terms, which could have a material adverse impact upon our business, including delaying a product launch or subjecting our commercialization efforts to significant supply risk. Even if we are able to enter into long-term agreements with manufacturers for commercial supply on reasonable terms, we may be unable to do so with sufficient time prior to the launch of our product candidates, which would expose us to substantial supply risk and potentially jeopardize our launch. See “Business—Manufacturing” for additional information.

Manufacturing issues may arise that could increase product and regulatory approval costs or delay commercialization.

As we scale up manufacturing of our product candidates and conduct required stability testing, product, packaging, equipment and process-related issues may require refinement or resolution in order to proceed with our planned clinical trials and obtain regulatory approval for commercial marketing. In the future, we may identify impurities, which could result in increased scrutiny by the regulatory agencies, delays in our clinical program and regulatory approval, increases in our operating expenses, or failure to obtain or maintain approval for our product candidates.

Guidelines and recommendations published by various organizations can reduce the use of our product candidates.

Government agencies promulgate regulations and guidelines directly applicable to us and to our product candidates. In addition, professional societies, such as practice management groups, private health and science foundations and organizations involved in various diseases from time to time may also publish guidelines or recommendations to the healthcare and patient communities. Recommendations of government agencies or these

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other groups or organizations may relate to such matters as usage, dosage, route of administration and use of concomitant therapies. Recommendations or guidelines suggesting the reduced use of our product candidates or the use of competitive or alternative products as the standard of care to be followed by patients and healthcare providers could result in decreased use of our product candidates.

We face significant competition from other biopharmaceutical companies, and our operating results will suffer if we fail to compete effectively.

Our industry is intensely competitive and subject to rapid and significant technological change. While we believe that our Asia based development platform, knowledge, experience and scientific resources provide us with competitive advantages, we face substantial competition from multinational pharmaceutical companies, specialty pharmaceutical companies and biotechnology companies, universities and other research institutions worldwide. For example, there are several targeted therapies currently in clinical development targeting specific subsets of biliary tract cancer, including ivosidenib being developed by Agios Pharmaceuticals, Inc., ARQ087 being developed by Arqule, Inc. and lenvatinib being developed by Eisai Inc. In addition, trastuzumab is approved in combination with chemotherapy for the treatment of first-line HER2-positive metastatic gastric cancer and there are other drugs approved for later lines of treatment including Eli Lilly and Company’s ramucirumab and Merck & Co., Inc.’s pembrolizumab. There are several other drugs in clinical development for first-line gastric cancer, including BMS’ nivolumab and pembrolizumab. Puma Biotechnology, Inc.’s neratinib is approved in adjuvant breast cancer, but is not currently being developed in gastric cancer or biliary tract cancer.

Many of our competitors have significantly greater financial, clinical and human resources. Additionally, small and early-stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies. As a result, our competitors may discover, develop, license or commercialize products before or more successfully than we do. Competition may increase further as a result of advances in the commercial applicability of technologies and greater availability of capital for investment in these industries. Our competitors may succeed in developing, acquiring or licensing on an exclusive basis drug products or drug delivery technologies that are more effective or less costly than our product candidates that we are currently developing or that we may develop.

We believe that our ability to successfully compete will depend on, among other things:

If our competitors market products that are more effective, safer or less expensive than our future products, if any, or that reach the market sooner than our future products, if any, we may not achieve commercial success. Because we have limited research and development capabilities, it may be difficult for us to stay abreast of the

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rapid changes in technology. If we fail to stay at the forefront of technological change, we may be unable to compete effectively. Technological advances or products developed by our competitors may render our technologies or product candidates obsolete, less competitive or not economical.

Price controls may adversely affect our future profitability.

In certain countries, prescription drug pricing and reimbursement is subject to governmental control. In those countries that impose price controls, pricing negotiations with governmental authorities can take considerable time after the receipt of marketing approval for a product. To obtain reimbursement or pricing approval in some countries, we or our strategic partners may be required to conduct a clinical trial that compares the cost-effectiveness of our product candidates to other available therapies.

Some countries require approval of the sale price of a drug before it can be marketed. In many countries, the pricing review period begins after marketing or product licensing approval is granted. In certain markets, prescription pharmaceutical pricing remains subject to continuing governmental control even after initial approval is granted. As a result, we or our strategic partners might obtain marketing approval for a product candidate in a particular country, but then be subject to price regulations that delay commercial launch of the product candidate, possibly for lengthy time periods, and negatively impact the revenue that we generate from the sale of the product in that country. If reimbursement of such product candidates is unavailable or limited in scope or amount, or if pricing is set at unsatisfactory levels, or if there is competition from lower priced cross-border sales, our profitability will be negatively affected.

Legislative or regulatory healthcare reforms may make it more difficult and costly for us to obtain regulatory clearance or approval of our product candidates and to produce, market and distribute our products after clearance or approval is obtained.

From time to time, legislation is drafted and introduced that could significantly change the statutory provisions governing the regulatory clearance or approval, manufacture and marketing of regulated products or the reimbursement thereof. In addition, U.S. FDA regulations and guidance are often revised or reinterpreted by the U.S. FDA in ways that may significantly affect our business and our products. Any new regulations or revisions or reinterpretations of existing regulations may impose additional costs or lengthen review times of our product candidates. We cannot determine what effect changes in regulations, statutes, legal interpretation or policies, when and if promulgated, enacted or adopted may have on our business in the future. Such changes could, among other things, require:

Each of these would likely entail substantial time and cost and could harm our business and our financial results.

In addition, in the United States, there have been a number of legislative and regulatory proposals to change the health care system in ways that could affect our ability to sell our products profitably. The pharmaceutical industry in the United States, as an example, has been affected by the passage of the Patient Protection and Affordable Care Act, as amended by the Health Care and Education Reconciliation Act of 2010, collectively PPACA, which, among other things, imposed new fees on entities that manufacture or import certain branded prescription drugs and expanded pharmaceutical manufacturer obligations to provide discounts and rebates to certain government programs. Since its enactment, there have been judicial and Congressional challenges to certain aspects of PPACA, as well as recent efforts by the Trump administration to repeal or replace certain aspects of PPACA. Since January 2017, President Trump has signed two Executive Orders and other directives

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designed to delay the implementation of certain provisions of PPACA or otherwise circumvent some of the requirements for health insurance mandated by PPACA. In addition, The Centers for Medicare and Medicaid Services, or CMS, an agency within the U.S. Department of Health and Human Services, has recently proposed regulations that would give states greater flexibility in setting benchmarks for insurers in the individual and small group marketplaces, which may have the effect of relaxing the essential health benefits required under the PPACA marketplaces. Further, Congress has considered legislation that would repeal or repeal and replace all or part of the PPACA. While Congress has not passed comprehensive repeal legislation, two bills affecting the implementation of certain taxes under the PPACA have been signed into law. 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 who 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, President Trump signed a continuing 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 cost employer-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, the Bipartisan Budget Act of 2018, or the BBA, among other things, amends the PPACA, effective January 1, 2019, to increase from 50 percent to 70 percent the point-of-sale discount that is owed by pharmaceutical manufacturers who participate in Medicare Part D and to close the coverage gap in most Medicare drug plans, commonly referred to as the “donut hole.” Congress will likely consider other legislation to repeal or repeal and replace other elements of PPACA. We continue to evaluate the effect that PPACA and its possible repeal and replacement has on our business. It is uncertain the extent to which any such changes may impact our business or financial condition.

Further, there has been particular and increasing legislative and enforcement interest in the United States with respect to drug pricing practices in recent years, particularly with respect to drugs that have been subject to relatively large price increases over relatively short time periods. There have been several recent Congressional inquiries and proposed and enacted federal and state legislation designed to, among other things, bring more transparency to drug pricing, review the relationship between pricing and manufacturer patient programs, and reform government program reimbursement methodologies for drugs. At the federal level, the Trump administration’s budget 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, measures to 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 generic drugs for low-income patients. While any proposed measures will require authorization through additional legislation to become effective, Congress and the Trump administration have each indicated that it will continue to seek new legislative and/or administrative measures to control drug costs. At the state level, legislatures are increasingly passing legislation and implementing regulations designed to control pharmaceutical and biological product pricing, including price or patient reimbursement constraints, discounts, restrictions on certain product access and marketing cost disclosure and transparency measures, and, in some cases, designed to encourage importation from other countries and bulk purchasing.

In the future, there will likely continue to be proposals relating to the reform of the U.S. healthcare system, some of which could further limit coverage and reimbursement of drug products, including our product candidates. Any reduction in reimbursement from Medicare or other government programs may result in a similar reduction in payments from private payors. Our results of operations could be adversely affected by PPACA and by other health care reforms that may be enacted or adopted in the future.

It may be difficult for us to profitably sell any future products that may be approved if coverage and reimbursement for these products is limited by government authorities and/or third-party payor policies.

In addition to any healthcare reform measures which may affect reimbursement, market acceptance and sales of our product candidates, if approved, will depend on, in part, the extent to which our products, and the procedures which utilize our products, will be covered by third-party payors, such as government health care programs,

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commercial insurance and managed care organizations. These third-party payors determine the extent to which new drugs, and the procedures which utilize new drugs, will be covered as a benefit under their plans and the level of reimbursement for any covered product and procedures utilizing such products. It is difficult to predict at this time what third-party payors will decide with respect to the coverage and reimbursement for our product candidates, and the procedures which utilize our product candidates.

A primary trend in the healthcare industry has been cost containment, including price controls, restrictions on coverage and reimbursement and requirements for substitution of generic products and/or biosimilars. Third- party payors decide which drugs, and procedures using such drugs, they will pay for and establish reimbursement and co-payment levels. Government and other third-party payors are increasingly challenging the prices charged for health care products and services, examining the cost effectiveness of drugs in addition to their safety and efficacy, and limiting or attempting to limit both coverage and the level of reimbursement for prescription drugs and the procedures which utilize prescription drugs. We cannot be sure that coverage will be available for our product candidates, and the procedures which utilize our product candidates, if approved, or, if coverage is available, the level of reimbursement.

There is significant uncertainty related to the insurance coverage and reimbursement of newly approved products, and the procedures which utilize such products. In the United States, the principal decisions about reimbursement for new medicines, and the procedures which utilize new medicines, are typically made by CMS, as CMS decides whether and to what extent a new medicine, and procedures which utilize a new medicine, will be covered and reimbursed under Medicare. Private payors may follow CMS, but have their own methods and approval processes for determining reimbursement for new medicines, and the procedures that utilize new medicines. It is difficult to predict what CMS or other payors will decide with respect to reimbursement for fundamentally novel products such as ours, as there is no body of established practices and precedents for these new products.

Reimbursement may 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, or a procedure which utilizes 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 and procedures for the treatment of their conditions, and their prescribing physicians, generally rely on third-party payors to reimburse all or part of the costs associated with those prescription drugs and procedures. Patients are unlikely to use our products, or agree to procedures utilizing our products, unless coverage is provided and reimbursement is adequate to cover all or a significant portion of the associated costs. Therefore, coverage and adequate reimbursement is critical to new product acceptance. 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 or subsequently become available. There may be significant delays in obtaining coverage and reimbursement for newly approved drugs, and the procedures which utilize newly approved drugs, and coverage may be more limited than the purposes for which such drug is approved by the U.S. FDA or comparable foreign regulatory authorities. Moreover, eligibility for coverage and reimbursement does not imply that a drug will be paid for in all cases or at a rate that covers our costs, including research, development, manufacture, sale and distribution.

We expect to experience pricing pressures in connection with the sale of any of our product candidates due to the trend toward managed healthcare, the increasing influence of health maintenance organizations, and additional legislative changes. The downward pressure on healthcare costs in general, particularly prescription drugs, medical devices and surgical procedures and other treatments, has become very intense. As a result, increasingly high barriers are being erected to the successful commercialization of new products. Further, the adoption and implementation of any future governmental cost containment or other health reform initiative may result in additional downward pressure on the price that we may receive for any approved product.

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Reimbursement by a third-party payor may depend upon a number of factors including the third-party payor’s determination that use of a product is:

Obtaining coverage and reimbursement approval for a product, or a procedure which utilizes a product, from a government or other third-party payor is a time-consuming and costly process that could require us to provide supporting scientific, clinical and cost effectiveness data for the use of our products, and the procedures which utilize our products, to the payor. Further, no uniform policy requirement for coverage and reimbursement for drug products, and procedures which utilize drug products, exists among third-party payors in the United States. Therefore, coverage and reimbursement for drug products, and the procedures which utilize drug products, can differ significantly from payor to payor. As a result, the coverage determination process may require us to provide scientific and clinical support for the use of our products to each payor separately, with no assurance that coverage and adequate reimbursement will be applied consistently or obtained in the first instance. We may not be able to provide data sufficient to gain acceptance with respect to coverage and/or sufficient reimbursement levels. We cannot be sure that coverage or adequate reimbursement will be available for our product candidates, or the procedures which utilize our product candidates, if approved. Also, we cannot be sure that reimbursement amounts will not reduce the demand for, or the price of, our future products. If reimbursement is not available, or is available only to limited levels, we may not be able to commercialize our product candidates, or achieve profitably at all, even if approved.

Reimbursement may not be immediately available for our product candidates in China, which could diminish our sales or affect our profitability.

In China, the Ministry of Human Resources and Social Security of China or provincial or local human resources and social security authorities, together with other government authorities, review the inclusion or removal of drugs from China’s National Drug Catalog for Basic Medical Insurance, Work-related Injury Insurance and Maternity Insurance, or the National Reimbursement Drug List, or the NRDL, or provincial or local medical insurance catalogues for the National Medical Insurance Program regularly, and the tier under which a drug will be classified, both of which affect the amounts reimbursable to program participants for their purchases of those drugs. These determinations are made based on a number of factors, including price and efficacy.

In February 2017, the Ministry of Human Resources and Social Security of China released a new edition of the NRDL. Prior to this, the last update of the NRDL occurred in 2009. Given the period of time between updates, it may take several years following approval of our product candidates to be included in the NRDL, if ever.

We may be subject, directly or indirectly, to federal and state healthcare fraud and abuse laws, false claims laws and health information privacy and security laws. If we are unable to comply, or have not fully complied, with such laws, we could face substantial penalties.

If we obtain U.S. FDA approval for any of our product candidates and begin commercializing those products in the United States, our operations will be directly or indirectly through our relationships with healthcare providers, patients and other persons and entities, subject to broadly applicable fraud and abuse and other healthcare laws and regulations that may constrain the business or financial arrangements and relationships through which we research, market, sell and distribute our products. In addition, we may be subject to patient

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privacy regulation by both the federal government and the states in which we conduct our business. The laws that may affect our ability to operate include:

The U.S. Anti-Kickback Statute prohibits, among other things, any person or entity from knowingly and willfully offering, paying, soliciting, receiving or providing any remuneration, directly or indirectly, overtly or covertly, to induce or in return for purchasing, leasing, ordering or arranging for or recommending the purchase, lease or order of any item or service reimbursable, in whole or in part, under Medicare, Medicaid or other U.S. federal healthcare programs. The Anti-Kickback Statute has been interpreted to apply to arrangements between pharmaceutical manufacturers on the one hand and prescribers, purchasers, and formulary managers on the other. There are a number of statutory exceptions and regulatory safe harbors protecting some common activities from prosecution.

The U.S. federal false claims and civil monetary penalties laws, including the False Claims Act, or FCA, which prohibit any person or entity from, among other things, knowingly presenting, or causing to be presented, a false, fictitious or fraudulent claim for payment to, or approval by, the U.S. federal government or knowingly making, using or causing to be made or used a false record or statement material to a false or fraudulent claim to the U.S. federal government. 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. In addition, manufacturers can be held liable under the FCA even when they do not submit claims directly to government payors if they are deemed to “cause” the submission of false or fraudulent claims. The FCA also permits a private individual acting as a “whistleblower” to bring actions on behalf of the federal government alleging violations of the FCA and to share in any monetary recovery. FCA liability is potentially significant in the healthcare industry because the statute provides for treble damages and mandatory penalties per false claim or statement. Government enforcement agencies and private whistleblowers have investigated pharmaceutical companies for or asserted liability under the FCA for a variety of alleged promotional and marketing activities, such as providing free product to customers with the expectation that the customers would bill federal programs for the product; providing consulting fees and other benefits to physicians to induce them to prescribe products; engaging in promotion for “off-label” uses; and submitting inflated best price information to the Medicaid Rebate Program.

HIPAA prohibits, among other actions, knowingly and willfully executing, or attempting to execute, a scheme to defraud any healthcare benefit program, including private third-party payors, knowingly and willfully embezzling or stealing from a healthcare benefit program, willfully obstructing a criminal investigation of a healthcare offense, and knowingly and willfully falsifying, concealing or covering up a material fact or making any materially false, fictitious or fraudulent statement in connection with the delivery of or payment for healthcare benefits, items or services.

The Physician Payments Sunshine Act, enacted as part of PPACA, imposes, among other things, annual reporting requirements for covered manufacturers for certain payments and “transfers of value” provided to physicians and teaching hospitals, as well as ownership and investment interests held by physicians and their immediate family members.

HIPAA, as amended by HITECH, and their respective implementing regulations, impose, among other things, specified requirements relating to the privacy, security and transmission of individually identifiable health information held by covered entities, which include certain healthcare providers, health plans and healthcare clearinghouses, and their business associates, which include individuals or entities that perform services for covered entities that involve the creation, use, maintenance or disclosure of, individually identifiable health information. HITECH also created new tiers of civil 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 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. In addition, state laws govern the privacy and security of health information in specified circumstances, many of which differ from each other in significant ways and may not have the same effect, thus complicating compliance efforts.

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Many U.S. states and other foreign jurisdictions have analogous laws and regulations, such as state anti-kickback and false claims laws, that may apply to sales or marketing arrangements and claims involving healthcare items or services reimbursed by non-governmental third-party payors, including private insurers. In addition, certain states require drug manufacturers to report information related to payments and other transfers of value to physicians and other healthcare providers or marketing expenditures and certain states and local jurisdictions require the registration of pharmaceutical sales representatives. Further, there are state laws governing the privacy and security of health information in certain circumstances, many of which differ from each other in significant ways and may not have the same effect, thus complicating compliance efforts.

Because of the breadth of these laws and the narrowness of the statutory exceptions and regulatory safe harbors available, it is possible that some of our business activities could be subject to challenge under one or more of such laws. In addition, recent health care reform legislation has strengthened these laws. For example, recent health care reform legislation, has among other things, amended the intent requirement of the U.S. Anti-Kickback Statute and criminal healthcare fraud statutes. A person or entity no longer needs to have actual knowledge of this statute or specific intent to violate it in order to have committed a violation. Moreover, recent health care reform legislation provides that the government may assert that a claim including items or services resulting from a violation of the U.S. Anti-Kickback Statute constitutes a false or fraudulent claim for purposes of the FCA.

Ensuring that our business arrangements with third parties comply with applicable healthcare laws and regulations will likely be costly. It is possible that governmental authorities will conclude that our business practices do not comply with current or future statutes, regulations or case law involving applicable fraud and abuse or other healthcare laws and regulations. If our operations were found to be in violation of any of these laws or any other governmental regulations that may apply to us, we may be subject to significant civil, criminal and administrative penalties, damages, fines, disgorgement, individual imprisonment, possible exclusion from government funded healthcare programs, contractual damages, reputational harm, diminished profits and future earnings, additional reporting obligations and oversight if we become subject to a corporate integrity agreement or other agreement to resolve allegations of non-compliance with these laws, and curtailment of our operations, any of which could substantially disrupt our operations. If the physicians or other providers or entities with whom we expect to do business are found not to be in compliance with applicable laws, they may be subject to criminal, civil or administrative sanctions, including exclusions from government funded healthcare programs.

We are subject to U.S. and foreign anti-corruption and anti-money laundering laws with respect to our operations and non-compliance with such laws can subject us to criminal and/or civil liability and harm our business.

We are subject to the U.S. Foreign Corrupt Practices Act of 1977, as amended, or the FCPA, the U.S. domestic bribery statute contained in 18 U.S.C. § 201, the U.S. Travel Act, the USA PATRIOT Act, and possibly other state and national anti-bribery and anti-money laundering laws in countries in which we conduct activities. Anti-corruption laws are interpreted broadly and prohibit companies and their employees, agents, third-party intermediaries, joint venture partners and collaborators from authorizing, promising, offering, or providing, directly or indirectly, improper payments or benefits to recipients in the public or private sector. We engage third party investigators, CROs, and other consultants to design and perform preclinical studies of our product candidates, and will do the same for any clinical trials. Also, once a product candidate has been approved and commercialized, we may engage third party intermediaries to promote and sell our products abroad and/or to obtain necessary permits, licenses, and other regulatory approvals. We or our third-party intermediaries may have direct or indirect interactions with officials and employees of government agencies or state-owned or affiliated entities. We can be held liable for the corrupt or other illegal activities of these third-party intermediaries, our employees, representatives, contractors, collaborators, partners, and agents, even if we do not explicitly authorize or have actual knowledge of such activities.

Noncompliance with anti-corruption and anti-money laundering laws could subject us to whistleblower complaints, investigations, sanctions, settlements, prosecution, other enforcement actions, disgorgement of

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profits, significant fines, damages, other civil and criminal penalties or injunctions, suspension and/or debarment from contracting with certain persons, the loss of export privileges, reputational harm, adverse media coverage, and other collateral consequences. If any subpoenas, investigations, or other enforcement actions are launched, or governmental or other sanctions are imposed, or if we do not prevail in any possible civil or criminal litigation, our business, results of operations and financial condition could be materially harmed. In addition, responding to any action will likely result in a materially significant diversion of management’s attention and resources and significant defense and compliance costs and other professional fees. In certain cases, enforcement authorities may even cause us to appoint an independent compliance monitor which can result in added costs and administrative burdens.

The incidence and prevalence for target patient populations of our product candidates are based on estimates and third-party sources. If the market opportunities for our product candidates are smaller than we estimate or if any approval that we obtain is based on a narrower definition of the patient population, our revenue and ability to achieve profitability might be materially and adversely affected.

Periodically, we make estimates regarding the incidence and prevalence of target patient populations for particular diseases based on various third-party sources and internally generated analysis and use such estimates in making decisions regarding our drug development strategy, including acquiring or in-licensing product candidates and determining indications on which to focus in preclinical or clinical trials.

These estimates may be inaccurate or based on imprecise data. For example, the total addressable market opportunity will depend on, among other things, acceptance of our drugs by the medical community and patient access, drug pricing and reimbursement. The number of patients in the addressable markets may turn out to be lower than expected, patients may not be otherwise amenable to treatment with our drugs, or new patients may become increasingly difficult to identify or gain access to, all of which may significantly harm our business, financial condition, results of operations and prospects.

Risks Related to our ADSs and This Offering

The price of our ADSs may be volatile and may fluctuate due to factors beyond our control.

The trading market for publicly traded emerging biopharmaceutical and drug discovery and development companies has been highly volatile and is likely to remain highly volatile in the future. The market price of our ADSs may fluctuate significantly due to a variety of factors, including:

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These and other market and industry factors may cause the market price and demand for our ADSs to fluctuate substantially, regardless of our actual operating performance, which may limit or prevent investors from readily selling their ADSs and may otherwise negatively affect the liquidity of our ADSs. In addition, the stock market in general, and biopharmaceutical companies in particular, have experienced extreme price and volume fluctuations that have often been unrelated or disproportionate to the operating performance of these companies. In the past, when the market price of a security has been volatile, holders of that security have sometimes instituted securities class action litigation against the issuer. If any of the holders of our ADSs were to bring such a lawsuit against us, we could incur substantial costs defending the lawsuit and the attention of our senior management would be diverted from the operation of our business. Any adverse determination in litigation could also subject us to significant liabilities.

There has been no public market for our ADSs prior to this offering, and an active market may not develop in which investors can resell our ADSs.

Prior to this offering, there has been no public market for our ADSs. We cannot predict the extent to which an active market for our ADSs will develop or be sustained after this offering, or how the development of such a market might affect the market price for our ADSs. The initial public offering price of our ADSs in this offering has been agreed upon between us and the underwriters based on a number of factors, including the trading price of our ordinary shares on the TPEx as of the date of this prospectus, as well as certain market conditions in effect at the time of this offering, which may not be indicative of the price at which our ADSs will trade following completion of this offering. Investors may not be able to sell their ADSs at or above the initial public offering price. In addition, investors may not be able to successfully withdraw the underlying ordinary shares of our ADSs for the reasons discussed under the risk factor titled “You may not be able to withdraw the underlying ordinary shares of our ADSs” described below. In connection with any withdrawal of any of our ordinary shares represented by ADSs, our ADSs will be surrendered to the depositary. Unless additional ADSs are issued, the effect of such transactions will be to reduce the number of outstanding ADSs and, if a significant number of transactions are effected, to reduce the liquidity of our ADSs. See “Description of American Depositary Shares.”

Restrictions on the ability to deposit our ordinary shares into our American depositary receipt facility may adversely affect the liquidity of our ADSs.

The ability to deposit our ordinary shares into our American depositary receipt facility for the issuance of ADSs is restricted by Republic of China, or ROC, law, which may adversely affect the liquidity of our ADSs. Under current ROC law and the Deposit Agreement, no person or entity, including the holders of ADSs and us, may deposit our ordinary shares in our American depositary receipt facility for the issuance of ADRs without specific approval of the Financial Supervisory Commission, or FSC, unless:

With respect to (iii) above, the depositary may issue ADSs against the deposit of those shares only if the total number of ADSs outstanding following the deposit will not exceed the number of ADSs previously approved by the FSC, plus any ADSs issued pursuant to the events described in items (i) and (ii) above. Issuance of additional ADSs under item (iii) above will be permitted to the extent that a corresponding number of previous ADSs have been cancelled.

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The price of our ADSs may be limited by the trading price of our ordinary shares on the TPEx.

Our ordinary shares have been listed on the TPEx since June 1, 2017 under the code “6497.” From June 1, 2017 through May 4, 2018, the closing price of our ordinary shares on the TPEx ranged from NT$31.80 per share to NT$62.50 per share (which would be approximately $1.07 per share to $2.11 per share, based on the exchange rate in effect as of May 3, 2018). The TPEx sets certain limitations on the trading volatility of our ordinary shares and applicable ROC law requires the price at which our ADSs are issued in this offering to not be lower than 90% of the closing price of our ordinary shares on the pricing date of this offering or an average of closing prices a certain number of days prior to the pricing date of this offering. In addition, there is currently a ten percent limit on the daily price movement on the TPEx. As a result of these limitations, the potential increase in trading price of any ADSs that you may purchase in this offering may be materially limited based on the perceived value of our ordinary shares on the TPEx. Similarly, decreases in the trading price of our ordinary shares on the TPEx due to the perceptions of investors in that market, which may be different from your own, may impact the value of your investment.

The cross listing of our ordinary shares and our ADSs following this offering may adversely affect the liquidity and value of our ADSs.

We cannot predict the effect of this cross listing on the value of our ordinary shares and ADSs. However, the cross listing of our ordinary shares and our ADSs may dilute the liquidity of these securities in one or both markets and may adversely affect the development of an active trading market for our ADSs in the United States. The price of our ADSs could also be adversely affected by trading in our ordinary shares on the TPEx. In addition, currency fluctuations as between the New Taiwan dollar and U.S. dollar may have an adverse impact on the value of our ADSs.

We will incur increased costs as a result of operating as a public company in the United States, and our senior management will be required to devote substantial time to new compliance initiatives and corporate governance practices.

As a public company, and particularly after we no longer qualify as an “emerging growth company,” or EGC, we will incur significant legal, accounting and other expenses that we did not incur previously. The Sarbanes-Oxley Act of 2002, the Dodd-Frank Wall Street Reform and Consumer Protection Act, the listing requirements of The Nasdaq Stock Market LLC, or Nasdaq, and other applicable securities rules and regulations impose various requirements on non-U.S. reporting public companies, including the establishment and maintenance of effective disclosure and financial controls and corporate governance practices. Our senior management and other personnel will need to devote a substantial amount of time to these 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. For example, we expect that these rules and regulations may make it more difficult and more expensive for us to obtain director and officer liability insurance, which in turn could make it more difficult for us to attract and retain qualified senior management personnel or members for our board of directors.

However, these rules and regulations are often subject to varying interpretations, in many cases due to their lack of specificity, and, as a result, their application in practice may evolve over time as new guidance is provided by regulatory and governing bodies. This could result in continuing uncertainty regarding compliance matters and higher costs necessitated by ongoing revisions to disclosure and governance practices.

Pursuant to Section 404 of the Sarbanes-Oxley Act of 2002, or Section 404, we will be required to furnish a report by our senior management on our internal control over financial reporting. However, while we remain an EGC we will not be required to include an attestation report on internal control over financial reporting issued by our independent registered public accounting firm. To prepare for eventual compliance with Section 404, once we no longer qualify as an EGC, we will be engaged in a process to document and evaluate our internal control over financial reporting, which is both costly and challenging. In this regard, we will need to continue to dedicate

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internal resources, potentially engage outside consultants, adopt a detailed work plan to assess and document the adequacy of internal control over financial reporting, continue steps to improve control processes as appropriate, validate through testing that controls are functioning as documented, and implement a continuous reporting and improvement process for internal control over financial reporting. Despite our efforts, there is a risk that we will not be able to conclude, within the prescribed timeframe or at all, that our internal control over financial reporting is effective as required by Section 404. If we identify one or more material weaknesses, it could result in an adverse reaction in the financial markets due to a loss of confidence in the reliability of our financial statements.

You may face difficulties in protecting your interests, and your ability to protect your rights through U.S. courts may be limited, because we are incorporated under Cayman Islands law, we conduct substantially all of our operations and all of our directors and executive officers reside outside of the United States.

We are an exempted company incorporated under the laws of the Cayman Islands. Our corporate affairs are governed by our Fifth Amended and Restated Memorandum and Articles of Association, or our Articles, the Companies Law (2016 Revision) of the Cayman Islands and the common law of the Cayman Islands. The rights of shareholders to take action against the directors, actions by minority shareholders and the fiduciary duties of our directors to us under Cayman Islands law are to a large extent governed by the common law of the Cayman Islands. The common law of the Cayman Islands is derived in part from comparatively limited judicial precedent in the Cayman Islands as well as from the common law of England and Wales, the decisions of whose courts are of persuasive authority, but are not binding, on a court in the Cayman Islands. Similarly, the rights of our shareholders and the fiduciary duties of our directors under Cayman Islands law are not as clearly established as they would be under statutes or judicial precedent in some jurisdictions in the United States. In particular, the Cayman Islands has a less developed body of securities laws than the United States, and some U.S. states, such as Delaware, have more fully developed and judicially interpreted bodies of corporate law than the Cayman Islands. In addition, Cayman Islands companies do not have standing to sue before the federal court of the United States.

Shareholders of Cayman Islands exempted companies like us have no general rights under Cayman Islands law to inspect corporate records or to obtain copies of lists of shareholders of these companies. Although our shareholders are permitted by our Articles to request access to our books and records, our directors have discretion under our Articles to determine whether or not, and under what conditions, our corporate records may be inspected by our shareholders, but are not obliged to make them available to our shareholders. This may make it more difficult for you to obtain the information needed to establish any facts necessary for a shareholder motion or to solicit proxies from other shareholders in connection with a proxy contest.

Certain corporate governance practices in the Cayman Islands, which is our home country, differ significantly from requirements for companies incorporated in other jurisdictions such as the United States. To the extent we choose to follow home country practice with respect to corporate governance matters, our shareholders may be afforded less protection than they otherwise would under rules and regulations applicable to U.S. domestic issuers.

As a result of all of the above, our public shareholders may have more difficulty in protecting their interests in the face of actions taken by management, members of the board of directors or controlling shareholders than they would as public shareholders of a company incorporated in the United States. For a discussion of significant differences between the provisions of the Companies Law of the Cayman Islands and the laws applicable to companies incorporated in the United States and their shareholders, see “Description of Share Capital and Governing Documents—Material Differences in Corporate Law.”

Future sales, or the possibility of future sales, of a substantial number of our ADSs or ordinary shares could adversely affect the price of our ADSs.

Future sales of a substantial number of our ADSs or ordinary shares, or the perception that such sales will occur, could cause a decline in the market price of our ADSs. ADSs issued and sold in this offering may be resold in the

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U.S. public market immediately without restriction. A portion of our ordinary shares outstanding prior to the completion of this offering held by our directors, officers and other holders of an aggregate of approximately 27,100,608 of our ordinary shares outstanding, or 20.8%, will be subject to the lock-up agreements described in “Ordinary Shares and ADSs Eligible for Future Sale” and “Underwriting.” If, after the end of such lock-up agreements, these shareholders sell substantial amounts of our securities in the public markets, or the market perceives that such sales may occur, the market price of our ADSs and our ability to raise capital through an issue of equity securities in the future could be adversely affected.

If you purchase ADSs in this offering, you will suffer immediate dilution of your investment.

We expect the initial public offering price of our ADSs in this offering to be substantially higher than the as adjusted net tangible book value per ADS, and per underlying ordinary share, prior to this offering. Therefore, if you purchase ADSs in this offering, you will pay a price per ADSs, and per underlying ordinary share, that substantially exceeds our net tangible book value per ADS, and per underlying ordinary share, after this offering. To the extent outstanding options are exercised for ordinary shares, you may experience further dilution. Based on the initial public offering price of $7.03 per ADS, you will experience immediate dilution of $4.77 per ADS, representing the difference between our as adjusted net tangible book value per ADS after giving effect to this offering and the offering price. See “Dilution.”

We may sell additional equity or debt securities or enter into other financing arrangements to fund our operations, which may result in dilution to our shareholders and holders of our ADSs and impose restrictions on our business.

In order to raise additional funds to support our operations, we may sell additional equity or debt securities, which could adversely impact our existing shareholders and new investors participating in this offering, as well as our business. The sale of additional equity or debt securities, or a combination of both, would result in the issuance of additional shares capital and dilution to our shareholders and holders of our ADSs.

The incurrence of indebtedness would result in increased fixed payment obligations and could also result in certain restrictive covenants, such as limitations on our ability to incur additional debt, limitations on our ability to acquire, sell or license intellectual property rights and other operating restrictions that could adversely impact our ability to conduct our business. In the event that we enter into collaborations or licensing arrangements to raise capital, we may be required to accept unfavorable terms, including relinquishing or licensing to a third party on unfavorable terms our rights to technologies or product candidates that we otherwise would seek to develop or commercialize ourselves or potentially reserve for future potential arrangements when we might be able to achieve more favorable terms.

Because we do not anticipate paying any cash dividends on our ADSs or ordinary shares in the foreseeable future, capital appreciation, if any, will be your sole source of potential gains and you may never receive a return on your investment.

We have not paid cash dividends in the past on our ordinary shares. We intend to retain earnings, if any, for use in our business and do not anticipate paying any cash dividends in the foreseeable future. As a result, capital appreciation, if any, on our ADSs or ordinary shares will be your sole source of potential gains for the foreseeable future, and you will suffer a loss on your investment if you are unable to sell your ADSs or the underlying ordinary shares at or above the price you pay for our ADSs or ordinary shares. Investors seeking cash dividends should not purchase our ADSs in this offering.

We have broad discretion in the use of the net proceeds from this offering and may not use them effectively.

Our senior management will have broad discretion in the application of the net proceeds from this offering and could spend the proceeds in ways that do not improve our results of operations or enhance the value of our ADSs.

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The failure by our senior management to apply these funds effectively could result in financial losses, cause the price of our ADSs to decline and delay the development of our product candidates. Pending their use, we may invest the net proceeds from this offering in a manner that does not produce income or that loses value.

Purchasers of our ADSs may not have the same voting rights as the holders of our ordinary shares and may not receive voting materials in time to be able to exercise their right to vote.

As a holder of our ADSs, you will only be able to exercise the voting rights with respect to the underlying ordinary shares in accordance with the provisions of the deposit agreement. Under the deposit agreement, you must vote by giving voting instructions to the depositary. Upon receipt of your voting instructions, the depositary will try to vote the underlying ordinary shares in accordance with these instructions. You will not be able to directly exercise your right to vote with respect to the underlying shares unless you withdraw the shares. When a general meeting is convened, you may not receive sufficient advance notice to withdraw the shares underlying your ADSs to allow you to vote with respect to any specific matter. After we notify the depository of the agenda for the shareholders’ meeting, the depositary will notify you of the upcoming vote and will arrange to deliver our voting materials to you once they are available. We have agreed to give the depositary at least 30 days’ prior notice of shareholder meetings. Nevertheless, we cannot assure you that you will receive the voting materials in time to ensure that you can instruct the depositary to vote your shares. In addition, the depositary and its agents are not responsible for failing to carry out voting instructions or for their manner of carrying out your voting instructions. This means that you may not be able to exercise your right to vote and you may have no legal remedy if the shares underlying your ADSs are not voted as you requested.

Except in limited circumstances, the depositary for our ADSs will give us a discretionary proxy to vote our ordinary shares underlying your ADSs if you do not vote at shareholders’ meetings, which could adversely affect your interests.

Under the deposit agreement for our ADSs, to the extent we have provided the depositary with at least 45 days’ notice of a proposed meeting, if voting instructions are not timely received by the depositary from you, you shall be deemed to have instructed the depositary to give a discretionary proxy to a person designated by us to vote the shares represented by your ADSs as desired. However, no such instruction shall be deemed given and no discretionary proxy shall be given (a) if we inform the depositary in writing that (i) we do not wish such proxy to be given, (ii) substantial opposition exists with respect to any agenda item for which the proxy would be given or (iii) the agenda item in question, if approved, would materially or adversely affect the rights of holders of shares and (b) unless we have provided the depositary with an opinion of our counsel to the effect that (a) the granting of such discretionary proxy does not subject the depositary to any reporting obligations in the Cayman Islands or the ROC, or by the ROC FSC or TPEx, (b) the granting of such proxy will not result in a violation of the laws, rules, regulations or permits of the Cayman Islands, the ROC, the ROC FSC or TPEx, (c) the voting arrangement and deemed instruction will be given effect under the laws, rules, regulations and permits of the Cayman Islands, the ROC, the ROC FSC and TPEx and (d) the granting of such proxy will not under any circumstances result in the depositary being treated as the beneficial owner of ADSs under the laws, rules, regulations or permits of the Cayman Islands, the ROC, the ROC FSC and TPEx.

The effect of this discretionary proxy is that, if you fail to give voting instructions to the depositary as to how to vote the ordinary shares underlying your ADSs at any particular shareholders’ meeting, you cannot prevent our ordinary shares underlying your ADSs from being voted at that meeting, absent the situations described above, and it may make it more difficult for shareholders to influence our management. Holders of our ordinary shares are not subject to this discretionary proxy.

You may not be able to withdraw the underlying ordinary shares of our ADSs.

Pursuant to ROC law, an ADS holder who is a non-ROC person wishing to withdraw and hold deposited ordinary shares from the ADS facility is required to appoint an eligible agent in the ROC for filing tax returns and making

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tax payments, or a Tax Guarantor. Such Tax Guarantor will be required to meet the qualifications set by the Ministry of Finance of the ROC and will act as the guarantor of the withdrawing ADS holder’s tax payment obligations. In addition, subject to certain limited exceptions, under current ROC law, repatriation of profits by a non-ROC withdrawing ADS holder is subject to the submission of evidence by the withdrawing ADS holder of the appointment of a Tax Guarantor to, and approval thereof by, the ROC tax authority and of tax clearance certificates or evidentiary documents issued by the Tax Guarantor. We cannot provide any assurances that a withdrawing ADS holder will be able to appoint and obtain approval from the tax authority in a timely manner or at all.

Pursuant to ROC law, an ADS holder who is not an ROC person or ROC entity wishing to present ADSs to the depositary for cancellation and withdrawal and holding of the Deposited Securities from the depositary receipt facility is required to register as a foreign investor with the Taiwan Stock Exchange, or TWSE, if the ADS holder has never been registered as foreign investor with the TWSE previously, for making investments in the ROC securities market prior to withdrawing and holding the underlying ordinary shares from the depositary receipts facility.

Additionally, pursuant to ROC law, such withdrawing ADS holder is required to appoint a local agent in the ROC to, on such ADS holder’s behalf, open a securities trading account with prior approval granted by the TWSE with a local securities brokerage firm (with qualification set by the FSC) and a bank account, pay ROC taxes, remit funds, exercise shareholder rights and perform such other functions as the ADS holder may designate upon such withdrawal. In addition, such withdrawing ADS holder is also required to appoint a custodian bank and open a custodian account to hold the securities and cash in safekeeping, make confirmations, settle trades and report all relevant information. Without making such appointment and the opening of such custodian account, the withdrawing ADS holder would be unable to hold or subsequently sell the deposited ordinary shares withdrawn from the ADR facility on the TPEx. The laws of the ROC applicable to the withdrawal of the underlying ordinary shares may change from time to time. We cannot provide any assurances that current law will remain in effect or that future changes of ROC law will not adversely affect the ability of ADS holders to withdraw deposited ordinary shares.

Purchasers of our ADSs may not receive distributions on our ordinary shares in the form of ADSs or any value for them if it is illegal or impractical to make them available to holders of ADSs.

The depositary for our ADSs has agreed to pay to purchasers of our ADSs the cash dividends or other distributions it or the custodian receives on our ordinary shares or other deposited securities after deducting its fees and expenses and certain taxes. Purchasers of our ADSs will receive these distributions in proportion to the number of our ordinary shares their ADSs represent. However, in accordance with the limitations set forth in the deposit agreement, it may be unlawful or impractical to make a distribution available to holders of ADSs. We have no obligation to take any other action to permit the distribution of our ADSs, ordinary shares, rights or anything else to holders of our ADSs. This means that purchasers of our ADSs may not receive the distributions we make on our ordinary shares or any value from them if it is unlawful or impractical to make them available to ADS holders. These restrictions may have a negative impact on the market value of our ADSs.

Purchasers of our ADSs may be subject to limitations on transfer of their ADSs.

ADSs are transferable on the books of the depositary. However, the depositary may close its transfer books at any time or from time to time when it deems expedient in connection with the performance of its duties. In addition, the depositary may refuse to deliver, transfer or register transfers of ADSs generally when our books or the books of the depositary are closed, or at any time if we or the depositary deems it advisable to do so because of any requirement of law or of any government or governmental body, or under any provision of the deposit agreement, or for any other reason in accordance with the terms of the deposit agreement.

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The rights of our shareholders may differ from the rights typically offered to shareholders of a U.S. corporation.

Our corporate affairs are governed by our Articles and by the laws governing Cayman Islands corporations and companies engaging in drug development, marketing and sales businesses, as well as by the common law of the Cayman Islands. Certain rights and responsibilities of our shareholders, ADS holders and members of our board of directors under Cayman law are different from those that apply to a Delaware corporation. For example, Directors of Cayman Islands exempted companies are required to observe certain fiduciary duties. These duties are owed to the Cayman Islands company and include the duty to act in the best interests of the company and the shareholders as a whole. However, the fiduciary duties of a director of a Cayman Islands exempted company may not be the same as the fiduciary duty of a director of a U.S. corporation. In addition, controlling shareholders of U.S. corporations owe fiduciary duties to minority shareholders, while shareholders (including controlling shareholders) of Cayman Islands companies owe no fiduciary duties to either to the company or to other shareholders. Further, the rights of our shareholders to bring shareholders’ suits against us or our board of directors under Cayman Islands law are much more limited than those of shareholders of a U.S. corporation. For example, under Cayman Islands law, a shareholder who wishes to bring a claim against a director would generally need to obtain permission from the courts to bring a derivative action, in the name of the company, against the director. This is because the director of a Cayman Islands exempted company owes duties to the company and not to individual shareholders. As a result, our shareholders may have more difficulty protecting their rights in connection with actions taken by our directors than they would as shareholders of a U.S. corporation. In addition, minority shareholders in a Cayman Islands exempted company have more limited rights than minority shareholders in a U.S. corporation in relation to mergers and similar transactions that the company may carry out. For example, if a merger under the Companies Law involving a Cayman Islands exempted company is approved by the requisite majority of shareholders, a dissenting minority shareholder would have the right to be paid the fair value of their shares (which, if not agreed between the parties, will be determined by the Cayman Islands court) if they follow the required procedures, subject to certain exceptions. Such dissenter rights differ substantially from the appraisal rights, which would ordinarily be available to dissenting shareholders of Delaware corporations. Further, if a takeover offer is made to the shareholders of a Cayman Islands exempted company and accepted by holders of 90% of the shares affected, the offeror may require the holders of the remaining shares to transfer such shares on the terms of the offer. An objection can be made to the Grand Court of the Cayman Islands but this is unlikely to succeed in the case of an offer which has been so approved unless there is evidence of fraud, bad faith or collusion. A minority shareholder in this scenario would have no rights comparable to the appraisal rights which would generally be available to a dissenting shareholder of a U.S. corporation in similar circumstances. See the section of this prospectus titled “Description of Share Capital and Governing Documents” for a description of the principal differences between the provisions of Cayman law applicable to us and the U.S. Delaware General Corporate Law relating to shareholders’ rights and protections.

We qualify as a foreign private issuer and, as a result, we will not be subject to U.S. proxy rules and will be subject to Exchange Act reporting obligations that permit less detailed and less frequent reporting than that of a U.S. domestic public company.

Upon the closing of this offering, we will report under the Exchange Act as a non-U.S. company with foreign private issuer status. Because we qualify as a foreign private issuer under the Exchange Act, we are exempt from certain provisions of the Exchange Act that are applicable to U.S. domestic public companies, including (i) the sections of the Exchange Act regulating the solicitation of proxies, consents or authorizations in respect of a security registered under the Exchange Act; (ii) the sections of the Exchange Act requiring insiders to file public reports of their stock ownership and trading activities and liability for insiders who profit from trades made in a short period of time; and (iii) the rules under the Exchange Act requiring the filing with the SEC of quarterly reports on Form 10-Q containing unaudited financial and other specified information, or current reports on Form 8-K upon the occurrence of specified significant events. In addition, our officers, directors and principal shareholders are exempt from the reporting and “short-swing” profit recovery provisions of Section 16 of the Exchange Act and the rules thereunder. Therefore, our shareholders may not know on a timely basis when our officers, directors and principal shareholders purchase or sell our ordinary shares or ADSs. In addition, foreign private issuers are not required to

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file their annual report on Form 20-F until the date that is four months after the end of each fiscal year, while U.S. domestic issuers that are accelerated filers are required to file their annual report on Form 10-K within 75 days after the end of each fiscal year. Foreign private issuers also are exempt from Regulation Fair Disclosure, aimed at preventing issuers from making selective disclosures of material information. As a result of the above, you may not have the same protections afforded to shareholders of companies that are not foreign private issuers.

As a foreign private issuer, we are permitted to adopt certain home country practices in relation to corporate governance matters that differ significantly from Nasdaq corporate governance listing standards. These practices may afford less protection to shareholders than they would enjoy if we complied fully with corporate governance listing standards.

As a foreign private issuer, we are permitted to take advantage of certain provisions in the Nasdaq listing rules that allow us to follow ROC law for certain governance matters. Certain corporate governance practices in the ROC may differ significantly from corporate governance listing standards. When our ADSs are listed on The Nasdaq Global Market, we intend to continue to follow ROC corporate governance practices in lieu of certain corporate governance requirements of Nasdaq. See “Management—Foreign Private Issuer Exemption.” Therefore, our shareholders may be afforded less protection than they otherwise would have under corporate governance listing standards applicable to U.S. domestic issuers.

We may lose our foreign private issuer status in the future, which could result in significant additional costs and expenses.

As discussed above, we are a foreign private issuer, and therefore, we are not required to comply with all of the periodic disclosure and current reporting requirements of the Exchange Act. The determination of foreign private issuer status is made annually on the last business day of an issuer’s most recently completed second fiscal quarter. We would lose our foreign private issuer status if, for example, more than 50% of our ordinary shares are directly or indirectly held by residents of the United States and we fail to meet additional requirements necessary to maintain our foreign private issuer status. If we lose our foreign private issuer status on this date, we will be required to file with the SEC periodic reports and registration statements on U.S. domestic issuer forms, which are more detailed and extensive than the forms available to a foreign private issuer. We will also have to mandatorily comply with U.S. federal proxy requirements, and our officers, directors and principal shareholders will become subject to the short-swing profit disclosure and recovery provisions of Section 16 of the Exchange Act. In addition, we will lose our ability to rely upon exemptions from certain corporate governance requirements under the Nasdaq listing rules. As a U.S. listed public company that is not a foreign private issuer, we will incur significant additional legal, accounting and other expenses that we will not incur as a foreign private issuer, and accounting, reporting and other expenses in order to maintain a listing on a U.S. securities exchange. These rules and regulations could also make it more difficult for us to attract and retain qualified members of our board of directors and more expensive to procure director and officer liability insurance.

We are an EGC and we cannot be certain if the reduced reporting requirements applicable to “emerging growth companies” will make our ADSs less attractive to investors.

We are an EGC as defined in the JOBS Act. For as long as we continue to be an EGC, we may take advantage of exemptions from various reporting requirements that are applicable to other public companies that are not EGCs, including not being required to comply with the auditor attestation requirements of Section 404, exemptions from the requirements of holding a nonbinding advisory vote on executive compensation and shareholder approval of any golden parachute payments not previously approved. As an EGC, we are able to report only two years of financial results and selected financial data compared to three and five years, respectively, for comparable data reported by other public companies. We may take advantage of these exemptions until we are no longer an EGC. We could be an EGC for up to five years, although circumstances could cause us to lose that status earlier, including if the aggregate market value of our ADSs and ordinary shares held by non-affiliates exceeds $700 million as of the end of our second fiscal quarter before that time, in which case we would no longer be an

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EGC as of the following December 31st (the last day of our fiscal year). We cannot predict if investors will find our ADSs less attractive because we may rely on these exemptions. If some investors find our ADSs less attractive as a result, there may be a less active trading market for our ADSs and the price of our ADSs may be more volatile.

If we fail to maintain an effective system of internal controls over financial reporting, we may not be able to accurately report our financial results or prevent fraud. As a result, shareholders could lose confidence in our financial and other public reporting, which would harm our business and the trading price of our ADSs.

Effective internal controls over financial reporting are necessary for us to provide reliable financial reports and, together with adequate disclosure controls and procedures, are designed to prevent fraud. Any failure to implement required new or improved controls, or difficulties encountered in their implementation could cause us to fail to meet our reporting obligations. In addition, any testing by us conducted in connection with Section 404, or any subsequent testing by our independent registered public accounting firm, may reveal deficiencies in our internal controls over financial reporting that are deemed to be material weaknesses or that may require prospective or retroactive changes to our financial statements or identify other areas for further attention or improvement. Inadequate internal controls could also cause investors to lose confidence in our reported financial information, which could have a negative effect on the trading price of our ADSs.

Management will be required to assess the effectiveness of our internal controls annually. However, for as long as we are an EGC under the JOBS Act, our independent registered public accounting firm will not be required to attest to the effectiveness of our internal controls over financial reporting pursuant to Section 404. An independent assessment of the effectiveness of our internal controls could detect problems that our management’s assessment might not. Undetected material weaknesses in our internal controls could lead to financial statement restatements requiring us to incur the expense of remediation and could also result in an adverse reaction in the financial markets due to a loss of confidence in the reliability of our financial statements.

If securities or industry analysts do not publish research, or publish inaccurate or unfavorable research, about our business, the price of our ADSs and our trading volume could decline.

The trading market for our ADSs will depend in part on the research and reports that securities or industry analysts publish about us or our business. If no or too few securities or industry analysts provide coverage or if one or more of the analysts who cover us downgrade our ADSs or publish inaccurate or unfavorable research about our business, the price of our ADSs would likely decline. If one or more of these analysts cease coverage of us or fail to publish reports on us regularly, demand for our ADSs could decrease, which might cause the price of our ADSs and trading volume to decline.

Our U.S. ADS Holders may suffer adverse tax consequences if we are characterized as a passive foreign investment company.

Generally, if for any taxable year (i) 75% or more of our gross income is passive income, or (ii) at least 50% of the average quarterly value of our assets are held for the production of, or produce, passive income, we would be characterized as a passive foreign investment company, or PFIC, for U.S. federal income tax purposes. For purposes of the above calculations, a non-U.S. corporation that directly or indirectly owns at least 25% by value of the shares of another corporation is treated as if it held its proportionate share of the assets of the other corporation and received directly its proportionate share of the income of the other corporation. Passive income generally includes dividends, interest, rents, royalties and capital gains. Based on estimates of our gross income and gross assets (including tangible assets and intangible assets based on the anticipated market value of our ordinary shares), our intended use of proceeds of this offering, and the nature of our business, we expect to be classified as a PFIC for the taxable year ending December 31, 2017 and for future taxable years. There can be no assurance, however, regarding our PFIC status for any taxable year. If we are characterized as a PFIC, our U.S. shareholders may suffer adverse tax consequences, including having gains realized on the sale of our ordinary

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shares treated as ordinary income, rather than as capital gain, the loss of the preferential rate applicable to dividends received on our ordinary shares by individuals who are U.S. Holders (as defined in “Material Income Tax Considerations—Material U.S. Federal Income Tax Considerations for U.S. Holders”), and having interest charges apply to distributions by us and the proceeds of share sales and having to comply with certain reporting requirements. Certain elections exist that may alleviate some of the adverse consequences of PFIC status and would result in an alternative treatment (such as mark-to-market treatment) of our ordinary shares; however, we do not intend to provide the information necessary for U.S. holders to make qualified electing fund elections if we are classified as a PFIC.

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SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus contains forward-looking statements that involve substantial risks and uncertainties. In some cases, you can identify forward-looking statements by the words “may,” “might,” “will,” “could,” “would,” “should,” “expect,” “intend,” “plan,” “objective,” “anticipate,” “believe,” “estimate,” “predict,” “potential,” “continue” and “ongoing,” or the negative of these terms, or other comparable terminology intended to identify statements about the future. These statements involve known and unknown risks, uncertainties and other important factors that may cause our actual results, levels of activity, performance or achievements to be materially different from the information expressed or implied by these forward-looking statements. The forward-looking statements and opinions contained in this prospectus are based upon information available to us as of the date of this prospectus and, while we believe such information forms a reasonable basis for such statements, such information may be limited or incomplete, and our statements should not be read to indicate that we have conducted an exhaustive inquiry into, or review of, all potentially available relevant information. Forward-looking statements include statements about:

You should refer to the section titled “Risk Factors” for a discussion of important factors that may cause our actual results to differ materially from those expressed or implied by our forward-looking statements. As a result of these factors, we cannot assure you that the forward-looking statements in this prospectus will prove to be accurate. Furthermore, if our forward-looking statements prove to be inaccurate, the inaccuracy may be material. In light of the significant uncertainties in these forward-looking statements, you should not regard these statements as a representation or warranty by us or any other person that we will achieve our objectives and plans in any specified time frame, or at all. We undertake no obligation to publicly update any forward-looking statements, whether as a result of new information, future events or otherwise, except as required by law.

You should read this prospectus and the documents that we reference in this prospectus and have filed as exhibits to the registration statement, of which this prospectus is a part, completely and with the understanding that our actual future results may be materially different from what we expect. We qualify all of our forward-looking statements by these cautionary statements.

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MARKET PRICE INFORMATION FOR OUR ORDINARY SHARES

Our ordinary shares have been listed on the TPEx since June 1, 2017 under the code “6497.” The following table sets forth, for the periods indicated, the high and low sales prices of our ordinary shares on the TPEx in New Taiwan dollars. On April 13, 2018, the closing price of our ordinary shares on the TPEx was NT$47.30 per share.

There are currently limits on the range of daily price movements on the TPEx. Fluctuations in the price of securities traded on the TPEx is restricted to 10% above and below the previous day’s closing.

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INDUSTRY AND MARKET DATA

This prospectus includes statistical and other industry and market data that we obtained from industry publications and research, surveys and studies conducted by third parties, as well estimates by our management based on such data. The market data and estimates used in this prospectus involve a number of assumptions and limitations, and you are cautioned not to give undue weight to such data and estimates. While we believe that the information from these industry publications, surveys and studies is reliable, the industry in which we operate is subject to a high degree of uncertainty and risk due to a variety of important factors, including those described in the section titled “Risk Factors.” These and other factors could cause results to differ materially from those expressed in the estimates made by the independent parties and by us.

TRADEMARKS, SERVICE MARKS AND TRADENAMES

The ASLAN Pharmaceuticals lion logo and other trademarks or service marks of ASLAN Pharmaceuticals Limited appearing in this prospectus are our property. Solely for convenience, the trademarks, service marks, logos and trade names referred to in this prospectus are without the ^® and ™ symbols, but such references are not intended to indicate, in any way, that we will not assert, to the fullest extent under applicable law, our rights or the rights of the applicable licensors to these trademarks, service marks and trade names. This prospectus contains additional trademarks, service marks and trade names of others, which are the property of their respective owners. All trademarks, service marks and trade names appearing in this prospectus are, to our knowledge, the property of their respective owners. We do not intend our use or display of other companies’ trademarks, service marks, copyrights or trade names to imply a relationship with, or endorsement or sponsorship of us by, any other companies.

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USE OF PROCEEDS

We estimate that the net proceeds from the sale of 6,000,000 ADSs in this offering will be approximately $36.8 million, after deducting the underwriting discounts and commissions and estimated offering expenses payable by us, based on the initial public offering price of $7.03 ADS. If the underwriters exercise their over-allotment option in full, we estimate that the net proceeds to us from this offering will be approximately $42.7 million, after deducting the underwriting discounts and commissions and estimated offering expenses payable by us.

The principal purposes of this offering are to increase our financial flexibility and create a public market in the United States for our securities. We currently expect to use the net proceeds from this offering, to continue to invest in the clinical development of our product candidates, including investing in the following planned and ongoing clinical trials as follows:

In connection with these trials, a portion of the net proceeds will also be used for manufacturing activities in preparation for a potential commercial launch. The remaining net proceeds, if any, are expected to fund new and other ongoing research and development activities, working capital and other general corporate purposes. Although we anticipate that the net proceeds from this offering will be sufficient to allow us to complete the global pivotal trial for varlitinib in biliary tract cancer, the China pivotal trial for varlitinib in biliary tract cancer, the global clinical trials for ASLAN003 in AML and the ASLAN004 preclinical and Phase 1 clinical trials, we currently do not expect the net proceeds from this offering will be sufficient to cover all of the expenses of the Phase 3 part of our global Phase 2/3 clinical trial for varlitinib in gastric cancer, which we expect will require approximately $50 million in additional funding. Furthermore, we will require additional capital beyond this offering in order to complete pivotal clinical trials of (except with respect to varlitinib in biliary tract cancer), file for regulatory approval for, or commercialize any of our product candidates. While we anticipate seeking additional capital in the future through further equity offerings and/or debt borrowings, or through collaboration agreements, strategic alliances, licensing arrangements or marketing and distribution arrangements, we cannot guarantee that we will be able to raise additional capital on reasonable terms or at all.

This expected use of the net proceeds from this offering represents our intentions based upon our current plans and prevailing business conditions, which could change in the future as our plans and prevailing business conditions evolve. Predicting the cost necessary to develop product candidates can be difficult and the amounts and timing of our actual expenditures may vary significantly depending on numerous factors, including the progress of our development, the status of and results from clinical trials, any collaborations that we may enter into with third parties for our product candidates and any unforeseen cash needs. As a result, our management will retain broad discretion over the allocation of the net proceeds from this offering.

Pending the application of the net proceeds as described above, we plan to invest them in short-term, interest bearing obligations, investment-grade instruments or certificates of deposit.

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DIVIDEND POLICY

We have never declared or paid a dividend, and we do not anticipate declaring or paying dividends in the foreseeable future. We intend to retain all available funds and any future earnings to fund the development and expansion of our business.

Under Cayman Islands law, dividends may be paid only out of profits, which include net earnings and retained earnings undistributed in prior years, and out of share premium, a concept analogous to paid-in surplus in the United States. No dividend may be declared and paid unless our directors determine that immediately after the payment, we will be able to satisfy our liabilities as they become due in the ordinary course of business and we have funds lawfully available for such purpose. We are not permitted to pay any dividends or bonuses if (a) we do not have earnings or (b) we have not yet covered our losses. Our Articles sets out further detailed provisions dealing with how we may fund, create reserves for and pay dividends. See “Description of Share Capital and Governing Documents.”

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CAPITALIZATION

The following table sets forth our cash and cash equivalents and capitalization as of December 31, 2017 on:

You should read this information together with our audited consolidated financial statements appearing elsewhere in this prospectus and the information set forth under the sections titled “Selected Consolidated Financial Data,” “Use of Proceeds” and “Management’s Discussion and Analysis of Financial Condition and Results of Operations.”

The number of ordinary shares outstanding in the table above does not include:

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DILUTION

If you invest in our ADSs in this offering, your interest will be immediately diluted to the extent of the difference between the portion of the initial public offering price per ADS in this offering attributable to each underlying ordinary share represented thereby and the net tangible book value per ordinary share after this offering. Dilution results from the fact that the portion of the initial public offering price per ADS attributable to each underlying ordinary share represented thereby is substantially in excess of the net tangible book value per ordinary share. As of December 31, 2017, we had a historical net tangible book value of $35.4 million, or $0.27 per ordinary share and $1.36 per ADS. Our net tangible book value per ordinary share represents total tangible assets less total liabilities, all divided by the number of ordinary shares outstanding on December 31, 2017.

After giving effect to the sale of 6,000,000 ADSs in this offering at the initial public offering price of $7.03 per ADS and after deducting the underwriting discounts and commissions and estimated offering expenses payable by us, our as adjusted net tangible book value at December 31, 2017 would have been $0.45 per ordinary share and $2.26 per ADS. This represents an immediate increase in as adjusted net tangible book value of $0.18 per ordinary share to existing investors and immediate dilution of $0.96 per ordinary share and $4.77 per ADS to new investors. The following table illustrates this dilution to new investors purchasing ADSs in this offering:

If the underwriters exercise their over-allotment option in full, the as adjusted net tangible book value per ADS after the offering would be $2.37, the increase in net tangible book value per ADS to existing shareholders would be $1.01, and the immediate dilution in net tangible book value per ADS to new investors in this offering would be $4.66.

The table and discussion above is based on 130,128,940 ordinary shares outstanding as of December 31, 2017 and does not include:

To the extent that share options are issued under our equity incentive plans, or we issue additional ordinary shares in the future, there will be further dilution to new investors participating in this offering.

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SELECTED CONSOLIDATED FINANCIAL DATA

The following tables summarize our selected consolidated financial data for the periods and as of the dates indicated. The selected consolidated statements of comprehensive loss data for the years ended December 31, 2016 and 2017 and the selected consolidated balance sheets data as of December 31, 2016 and 2017 have been derived from our audited consolidated financial statements, which have been prepared in accordance with IFRS, as issued by the IASB, and audited in accordance with the standards of the Public Company Accounting Oversight Board (United States), and included elsewhere in this prospectus. Our historical results are not necessarily indicative of the results that may be expected in the future. The following summary consolidated financial data should be read in conjunction with “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and our consolidated financial statements included elsewhere in this prospectus.

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MANAGEMENT’S DISCUSSION AND ANALYSIS

OF FINANCIAL CONDITION AND RESULTS OF OPERATIONS

You should read the following discussion and analysis of our financial condition and results of operations together with our consolidated financial statements and related notes appearing elsewhere in this prospectus. Some of the information contained in this discussion and analysis or set forth elsewhere in this prospectus, including information with respect to our plans and strategy for our business and related financing, includes forward-looking statements that involve risks and uncertainties. As a result of many factors, including those factors set forth in the “Risk Factors” section of this prospectus, our actual results could differ materially from the results described in or implied by the forward-looking statements contained in the following discussion and analysis.

Overview

We are a clinical-stage oncology-focused biopharmaceutical company based in Singapore developing novel therapeutics for global markets. We target diseases that are both highly prevalent in Asia and orphan indications in the United States and Europe. Our Asia development platform is designed to enable us to accelerate the development of drugs to treat these diseases. Our portfolio is comprised of four product candidates which target: validated growth pathways applied to new patient segments; novel immune checkpoints; and novel cancer metabolic pathways.

Our lead program, varlitinib, is a reversible small molecule pan-HER inhibitor that targets the human epidermal growth factor receptors HER1, HER2 and HER4. Varlitinib is currently being studied in a global pivotal clinical trial for biliary tract cancer for which we expect to report topline data in 2019. We are also conducting a global Phase 2/3 clinical trial of varlitinib for gastric cancer for which we expect to report topline Phase 2 data in the second half of 2018.

We focus on cancers, such as gastric cancer and biliary tract cancer, that are orphan diseases in the United States and Europe for which there are few, if any, approved therapies. Although registration trials for orphan diseases may require fewer patients, recruitment for such trials in the United States and Europe is challenging given the limited availability of suitable patients. Asia offers a unique opportunity to accelerate the development of novel therapies in diseases where either the cancers are more prevalent or the availability of suitable patients is greater.

Since our inception in 2010, we have devoted substantially all of our resources to acquiring rights to, and developing our product candidates, including preclinical studies and clinical trials and providing general and administrative support for our operations. We have not generated any revenue from product sales and we do not currently have any products approved for commercialization. We have financed our operations through a combination of debt and equity financings and government grants. Since inception we have raised $125.0 million from the sale of our ordinary shares including $33.0 million in a public offering conducted in Taiwan on June 1, 2017 and our ordinary shares are listed on the TPEx. We recorded $11.5 million of revenue for the year ended December 31, 2016, which was generated primarily through out-licensing activities. We did not generate revenue for the year ended December 31, 2017. To date we have outsourced our manufacturing and clinical operations to third parties. We do not intend to operate our own clinical trials or build or acquire infrastructure for manufacturing our drugs for clinical or commercial supply. All of our clinical supplies are manufactured in accordance with cGMP using high quality contract manufacturing organizations based in the United States, Europe and Asia.

As of December 31, 2016, and 2017, we had cash and cash equivalents of $51.7 million and $50.6 million, respectively. We have never been profitable and have incurred significant net losses in each period since our inception. Our net losses were $9.0 million and $39.9 million for the years ended December 31, 2016 and 2017, respectively. As of December 31, 2016 and 2017, we had an accumulated deficit of $50.4 million and $90.3 million, respectively. Substantially all of our losses have resulted from funding our research and development

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programs and general and administrative costs associated with our operations. We expect to continue to incur significant expenses and operating losses for the foreseeable future. We expect our expenses will increase substantially in connection with our ongoing activities as we:

We will continue to require additional capital to support our operating activities as we advance our product candidates through clinical development (except with respect to varlitinib in biliary tract cancer), regulatory approval and, if any of our product candidates are approved, commercialization. The amount and timing of our future funding requirements will depend on many factors, including the pace and results of our product development efforts.

Out-licensing Agreements

To date, we have out-licensing arrangements with BMS and Hyundai.

BMS

On November 2, 2011, we entered into a license agreement with BMS, pursuant to which we received exclusive rights to develop and commercialize ASLAN002 in China, Australia, South Korea, Taiwan and other selected Asian countries, and BMS retained exclusive rights in the rest of the world. On July 19, 2016, BMS initiated their rights pursuant to the agreement to buy back the exclusive rights from us to develop and commercialize ASLAN002. In connection with the buy-back, we received an upfront payment of $10.0 million in 2016, and are eligible to receive additional payments upon BMS’s achievement of development and regulatory milestones in the future. Furthermore, we are eligible to receive royalty payments on future worldwide sales generated by BMS. BMS also purchased from us research materials, supplies, research documentation and clinical trial results related to ASLAN002 for $1.2 million, which was paid in 2016. As BMS has assumed the responsibility for all development and commercialization activities and expenses and we have no further obligations under the license agreement, we have recognized $11.2 million in revenue for the year ended December 31, 2016. Since the conditions enabling capitalization of research and development costs related to ASLAN002 as an asset were not met and the research supplies related to ASLAN002 had no alternative future uses if the project is abandoned, all research and development expenditures were recognized in profit or loss when incurred. As a result, no cost of revenue was recorded in connection with the revenue recognized for the year ended December 31, 2016.

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Hyundai

On October 30, 2015, we entered into a collaboration and license agreement with Hyundai, pursuant to which we granted Hyundai to the right to develop and an option to commercialize varlitinib for the treatment of cholangiocarcinoma in South Korea. In consideration of the rights granted to Hyundai under the agreement, we received an upfront payment of $0.3 million from Hyundai in 2016. As we are not obligated to perform further activities, such payment was recognized as revenue, and the related cost of royalty in the amount of $0.1 million paid to one of the third parties with whom we have a licensing agreement as part of the payment for the proceeds from out-licensing was recognized as cost of revenue, for the year ended December 31, 2016. Hyundai also retains options to obtain development and commercialization rights for varlitinib for the treatment of gastric cancer and breast cancer in South Korea.

In-licensing Agreements

We are required to make milestone payments upon the achievement of certain development, regulatory and commercial milestones and royalties based on the net sales of the licensed products and therefore, we expect our results of operations will continue to be affected by these agreements. In 2016, we made a payment of less than $0.1 million to Exploit Technologies Pte Ltd to acquire their license that was capitalized as intangible assets. We have not made any other payments related to the in-license agreements. See “Business—License and Collaboration Agreements” for a description of our license agreements, which includes a description of the termination provisions of these agreements.

Financial Operations Overview

Revenue

To date, we have not generated any revenue from product sales and do not expect to generate any revenue from product sales until our product candidates receive regulatory approval. For the year ended December 31, 2016, revenues consisted primarily of upfront payments received under out-licensing arrangements, as described above. We did not generate revenue for the year ended December 31, 2017.

Cost of Revenue

In connection with the upfront payment that we received from Hyundai in 2016, we made a $0.1 million payment to one of the third parties with whom we have a licensing agreement, and such payment was recognized as costs of revenue for the year ended December 31, 2016. We did not recognize costs of revenue for the year ended December 31, 2017.

Research and Development Expenses

The largest component of our operating expenses since inception has been research and development activities, including the preclinical and clinical development of our product candidates. Research and development costs are expensed as incurred. Our research and development expenses primarily consist of:

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Product candidates in later stages of clinical development generally have higher development costs than those in earlier stages of clinical development, primarily due to the increased size and duration of later-stage clinical trials. Accordingly, we expect research and development costs to increase significantly for the foreseeable future as our programs progress. However, we do not believe that it is possible at this time to accurately project total program-specific expenses through commercialization. Our expenditures on current and future preclinical and clinical development programs are subject to numerous uncertainties in timing and cost to completion. In addition, we may enter into additional collaboration arrangements for our product candidates which could affect our development plans or capital requirements.

We allocate direct costs to product candidates when they enter into clinical development. For product candidates in clinical development, we allocate development and manufacturing costs to our product candidates on a program-specific basis, and we include these costs in the program-specific expenses. Our direct research and development expenses tracked by program consist primarily of external costs, such as fees paid to outside consultants, CROs, and CMOs in connection with our preclinical development, manufacturing and clinical development activities. We do not allocate employee costs or facility expenses, including other indirect costs, to specific programs because these costs are deployed across multiple programs and, as such, are not separately presented. We use internal resources primarily to oversee research and discovery as well as for managing our preclinical development, process development, manufacturing and clinical development activities. These employees work across multiple programs and, therefore, we do not track their costs by program.

The table below summarizes our research and development expenses incurred by program for the periods presented:

General and Administrative Expenses

General and administrative expenses consist of personnel costs, allocated expenses and other expenses for outside professional services, including legal, audit and accounting services. Personnel costs consist of salaries, bonuses, benefits and stock-based compensation. Other general and administrative expenses include facility-related costs not otherwise allocated to research and development expense, professional fees, expenses associated with obtaining and maintaining patents and costs of our information systems. We anticipate that our general and administrative expenses will continue to increase in the future as we increase our headcount to support our continued research and development and potential commercialization of our product candidates, as well as expenses related to compliance with the rules and regulations of the Securities and Exchange Commission, additional insurance expenses, investor relation activities and other administrative and professional fees.

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Non-Operating Income and Expenses

Other Gains, Net

Other gains are primarily net gains from realized and unrealized currency exchange differences incurred during the period.

Finance Costs

Finance costs are interest expenses primarily from the Singapore Economic Development Board, or EDB, repayable grant and the loan facility with CSL Finance Pty Ltd, or CSL Finance, as well as dividend accruals for preference shares from January to May 2016, all of which were converted into ordinary shares on May 27, 2016 in connection with our initial public offering in Taiwan. As of December 31, 2016 and 2017, there were no amounts outstanding under this facility.

Results of Operations

Comparison of the Years Ended December 31, 2016 and 2017

The following table sets forth a summary of our consolidated results of operations for the periods indicated. This information should be read together with our consolidated financial statements and related notes included elsewhere in this prospectus. Our operating results in any period are not necessarily indicative of the results that may be expected for any future period.

Revenue

Revenue was $11.5 million for the year ended December 31, 2016, consisting primarily of an upfront milestone payment of $10.0 million from BMS, a payment of $1.2 million from BMS for the sale of research materials, supplies, research documentation and clinical trial results related to ASLAN002, as well as a payment of

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$0.3 million from Hyundai related to the out-licensing of varlitinib in South Korea. We did not generate revenue for the year ended December 31, 2017.

General and Administrative

The following table sets forth a summary of our general and administrative expenses for the periods indicated.

General and administrative expenses for the years ended December 31, 2016 and 2017 were $6.9 million and $9.1 million, respectively. The increase in general and administrative expenses was primarily due to an increase in headcount and staffing costs, fund raising activity costs and office administration costs.

Research and Development

The following table sets forth a summary of our research and development expenses for the periods indicated.

Research and development expenses for the years ended December 31, 2016 and 2017 were $13.2 million and $30.0 million, respectively, consisting of expenditures relating to clinical development and clinical manufacturing work performed for our various product candidates. This was primarily due to the increased spending on the clinical trial activities and product manufacturing in connection with the development of our lead product candidate, varlitinib.

Other Gains and Losses, Net

Other net gains for the year ended December 31, 2016 were $0.1 million and other net losses for the year ended December 31, 2017 were $0.7 million, consisting primarily of realized and unrealized foreign exchange losses. The increase in net losses was primarily attributable to foreign currency translation losses as a result of the translation of our assets, liabilities and results of operations into U.S. dollars using the relevant foreign currency exchange rates. This was caused by the strengthening of the Singapore dollar against the U.S. dollar during those years.

Finance Costs

Finance costs for the years ended December 31, 2016 and 2017 were $0.5 million and $0.4 million, respectively, consisting primarily of interest expense related to interest accrued on long-term borrowings. The decrease was primarily due to the repayment of the CSL Finance loan facility in 2016 that resulted in less interest expenditure generated in 2017.

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Interest Income

Interest income for the years ended December 31, 2016 and 2017 were $0.1 million and $0.4 million, respectively. The increase was primarily due to an increase in deposits in banks in 2017 that resulted in more interest income generated in 2017.

Net Loss Attributable to Ordinary Shareholders

For the years ended December 31, 2016 and 2017, we had a net loss attributable to ordinary shareholders of $9.0 million and $39.9 million, respectively. The increases in research and development expenses, general and administrative expenses and non-operating expenses were the key drivers of the increased expenditure in 2017.

Liquidity and Capital Resources

Since our inception, we have invested most of our resources in the development of our product candidates, building our intellectual property portfolio, developing our supply chain, conducting business planning, raising capital and providing support for our operations. To date we have funded our operations through public and private placements of equity securities, upfront and milestone payments received from our collaborators, funding from governmental bodies and interest income from banks. Through December 31, 2017 we had raised aggregate gross proceeds of $125 million from private and public offerings, we had received aggregate gross upfront payments of $10.3 million from our collaborators and received an aggregate of $7.4 million in grants from government bodies. We have incurred net losses of $9.0 million and $39.9 million for the years ended December 31, 2016 and 2017, respectively. Net cash used in operating activities was $5.8 million and $34.1 million for the years ended December 31, 2016 and 2017, respectively. As of December 31, 2016 and 2017, we had an accumulated deficit of $50.4 million and $90.3 million, respectively, working capital of $49.3 million and $44.7 million, respectively, and cash and cash equivalents of $51.7 million and $50.6 million, respectively.

Cash Flows

The following table summarizes our cash flows for the periods presented :

Net Cash Used in Operating Activities

The use of cash resulted primarily from our net losses adjusted for non-cash charges and changes in components of our operating assets and liabilities. The primary cash inflow was generated from the consideration received for the out-licensing of experimental drugs. The primary use of our cash was to fund the development of our research and development activities, regulatory and other clinical trial costs, and related supporting administration. Our prepayments and other current assets, accounts payable and other payables balances were affected by the timing of vendor invoicing and payments.

Net cash used in operating activities were $5.8 million and $34.1 million for the years ended December 31, 2016 and 2017, respectively. The increase of net cash used in operating activities for 2017 was primarily due to the fact that no revenue was generated in 2017, compared to revenue of $11.5 million generated from out-licensing activities in 2016, and an increase of $16.8 million related to research and development expenses from 2016 to 2017 as we incurred more expenditures for our clinical trial activities of varlitinib and manufacturing activities in connection with the development of our various product candidates.

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Net Cash Used in Investing Activities

Net cash used in investing activities was $0.5 million and $0.3 million for the years ended December 31, 2016 and 2017, respectively. The decrease of net cash used in investing activities for 2017 was primarily due to lower expenditures related to office equipment and leasehold improvements and intangible assets.

Net Cash Provided by Financing Activities

Net cash provided by financing activities was $31.0 million and $33.3 million for the years ended December 31, 2016 and 2017, respectively, which consisted primarily of the net proceeds from our initial public offering in Taiwan in 2017 and net proceeds from our private financings in 2016.

Sources of Liquidity and Plan of Operation

We have not achieved profitability since our inception and we expect to continue to incur net losses for the foreseeable future. We expect our cash expenditures to increase in the near term as we fund future clinical trials for our lead program, varlitinib, as well as clinical trials of our other product candidates and continuing preclinical activities. We are already a publicly-traded company in Taiwan on the TPEx. Following this offering, we will also be a publicly-traded company in the U.S. and will incur more significant legal, accounting and other expenses. We expect compliance with U.S. rules and regulations will increase our legal and financial compliance costs and will make some activities more time-consuming and costly.

We believe that, based upon our current operating plan, our existing capital resources, together with the net proceeds from this offering, will be sufficient to fund our anticipated operations for at least the next 12 months, including development of varlitinib, development activities for our other additional product candidates, and for other discovery and development activities. We have based this estimate on assumptions that may prove to be wrong, and we could use our available capital resources sooner than we currently expect. If our planned preclinical and clinical trials are successful, or our other product candidates enter clinical trials or advance beyond the discovery stage, we will need to raise substantial additional financing in the future to fund our operations. In order to meet these additional cash requirements, we may incur debt, out-license certain intellectual property and seek to sell additional equity or convertible securities that may result in dilution to our stockholders. If we raise additional funds through the issuance of equity or convertible securities, these securities could have rights or preferences senior to those of our ADSs and ordinary shares and any indebtedness could contain covenants that restrict our operations. There can be no assurance that we will be able to obtain additional equity or debt financing on terms acceptable to us, if at all.

EDB Repayable Grant

On April 27, 2011, EDB awarded us a repayable grant, or the Grant, not exceeding approximately $7.4 million (SG$10 million) to support our drug development activities over a five-year qualifying period commencing February 24, 2011, or the Project. The Project was successfully implemented, resulting in substantially the full amount of the Grant being disbursed to us.

In the event any of our clinical product candidates achieve commercial approval after Phase 3 clinical trials, we will be required to repay the funds disbursed to us under the Grant plus interest of 6%. Until we have fulfilled our repayment obligations under the Grant, we have ongoing update and reporting obligations to the EDB. In the event we breach any of our ongoing obligations under the Grant, EDB can revoke the Grant and demand that we repay the funds disbursed to us under the Grant.

As of December 31, 2017, the amount of funds disbursed to us plus accrued interest was approximately $9.7 million.

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CSL Loan Facility

We have a loan facility with CSL Finance Pty Ltd. Amounts drawn down under the facility are repayable ten years from the date of the facility agreement. Interest on the facility is computed at 6% plus LIBOR and is payable on a quarterly basis. Amounts outstanding under the facility are required to be prepaid upon a successful product launch or our initial public offering. As of December 31, 2017, approximately $4.1 million was available to borrow under the facility.

Contractual Obligations and Commitments

The following is a summary of our contractual cash obligations as of December 31, 2017 (in thousands).

The table above does not include:

Purchase Commitments

Other than amounts as described above, we have no material non-cancelable purchase commitments with contract manufacturers or service providers as we have generally contracted on a cancelable basis.

Off-Balance Sheet Arrangements

We did not have during the periods presented, and we do not currently have, any off-balance sheet arrangements, as defined by applicable SEC regulations.

Quantitative and Qualitative Disclosures about Market Risk

Our financial risk management objective is to monitor and manage the financial risks relating to our operations. These risks include risks in financial markets (including currency risk, interest rate risk and other price risk), credit risk and liquidity risk. In order to minimize the effect of financial risks, we devote time and resources to identifying and evaluating the uncertainty of the financial market to mitigate risk exposures.

Our activities expose us primarily to risks of changes in foreign currency exchange rates, interest rates and other price risks.

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Foreign Exchange Risk

We have foreign currency transactions, which expose us to foreign currency risks. The significant financial assets and liabilities denominated in foreign currencies as of December 31, 2017 were as follows:

A hypothetical rate change of 5% is used when reporting foreign currency risk internally to key management personnel and represents management’s assessment of the reasonably possible change in foreign exchange rates. Based on outstanding foreign currency-denominated monetary items, a 5% weakening of the U.S. dollar against the Singapore dollar would result in a $0.4 million increase to net loss and decrease to equity for the year ended December 31, 2017.

Interest Rate Risk

We are exposed to interest rate risk because we have historically borrowed and from time to time may borrow funds at both fixed and floating interest rates. Our interest rate risk was mainly concentrated in the fluctuation of the benchmark interest rates arising from long-term borrowings.

The sensitivity analysis below was determined based on our exposure to interest rates for both derivatives and non-derivative instruments at the end of the reporting period. For floating rate liabilities, the analysis was prepared assuming the amount of the liability outstanding at the end of the reporting period was outstanding for the whole year. A hypothetical 100 basis point increase or decrease is used when reporting interest rate risk internally to key management personnel and represents management’s assessment of the reasonably possible change in interest rates. A 100 basis points increase in interest rates with all other variables held constant would result in a $0.1 million increase to our net loss and decrease to equity for the year ended December 31, 2017.

Critical Accounting Policies and Significant Judgments and Estimates

Critical Accounting Policies

Summarized below are our accounting policies that we believe are important to the portrayal of our financial results and also involve the need for management to make estimates about the effect of matters that are uncertain in nature. Actual results may differ from these estimates, judgments and assumptions. Certain accounting policies are particularly critical because of their significance to our reported financial results and the possibility that future events may differ significantly from the conditions and assumptions underlying the estimates used and judgments made by our management in preparing our financial statements. The following discussion should be read in conjunction with our consolidated financial statements and related notes, which are included in this prospectus.

Revenue Recognition

Revenue comprises the fair value of the consideration received or receivable for the out-licensing of experimental drugs that have reached ‘proof of concept’ to business partners for ongoing global development and launch, in the ordinary course of our activities. Revenue is presented, net of goods and services tax, rebates and discounts.

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We recognize revenue when we have completed the out-licensing of the experimental drug to business partners, such partners have accepted the products, and collectability of the related receivables is reasonably assured.

Typically income from out-licensing may take the form of upfront fees, milestones and/or sales royalties. Revenue is recognized upon the receipt of non-refundable upfront payments if the license of intellectual property has stand-alone value and we have no remaining obligation to perform subsequently in accordance with the licensing agreements. Otherwise, revenue recognition is deferred and spread over the period of performance on a straight-line basis. Milestone payments which are contingent on achieving certain clinical milestones are recognized as revenues either on achievement of such milestones, or over the period if we have continuing performance obligations. Royalties on marketed drugs, which are recognized as revenue on an accrual basis in accordance with the substance of the contracts, are recognized when it is probable that the economic benefits of a transaction will flow to us, and the revenue can be measured reliably.

Realization of Deferred Income Tax Assets

When we have net operating loss carry forwards or temporary differences in the amount of tax recorded for tax purposes and accounting purposes, we may be able to reduce the amount of tax that we would otherwise be required to pay in future periods. We generally recognize deferred tax assets to the extent that it is probable that sufficient taxable benefits will be available to utilize. The income tax benefit or expense is recorded when there is a net change in our total deferred tax assets and liabilities in a period. The ultimate realization of the deferred tax assets depends upon the generation of future taxable income during the periods in which the net operating losses and temporary differences become deductible may be utilized. Since the determination of the amount of realization of the deferred tax assets is based, in part, on our forecast of future profitability, it is inherently uncertain and subjective. In cases where the actual profits generated are less than expected, a material adjustment of deferred tax assets may arise, which would be recognized in profit or loss for the period in which such adjustment takes place. As of December 31, 2016 and 2017, no deferred tax asset has been recognized on tax losses due to the unpredictability of future profit streams.

Research and Development Expenses

Research and development expenditures are capitalized only if development costs can be measured reliably, the product or process is technically and commercially feasible, future economic benefits are probable, and we intends to and has sufficient resources to complete development and to use or sell the asset. The conditions enabling capitalization of development costs as an asset have not yet been met and, therefore, all development expenditures are recognized in the consolidated statement of operations when incurred.

Share-Based Compensation

As of December 31, 2017, there were options outstanding to purchase 14,530,879 ordinary shares. The options granted are valid for 10 years and are initially exercisable for 25% with the remaining 75% vesting in 25% increments over the three-year vesting schedule.

Equity-settled share-based payments to employees are measured at the fair value of the equity instruments at the grant date.

The fair value determined at the grant date of the employee share options is expensed on a straight-line basis over the vesting period, based on the estimate of employee share options that will eventually vest, with a corresponding increase in capital surplus—employee share options. The fair value determined at the grant date of the employee share options is recognized as an expense in full at the grant date when the share options granted vest immediately.

At the end of each reporting period, we revise our estimate of the number of employee share options expected to vest. The impact of the revision of the original estimates is recognized in profit or loss such that the cumulative

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expense reflects the revised estimate, with a corresponding adjustment to the capital surplus—employee share options.

We are responsible for determining the fair value of the stock options granted to employees following the regulatory requirements of the TPEx and using various information, including information provided by an independent third party valuation firm. The binomial option pricing model is applied in determining the estimated fair value of the options granted to employees. See footnote 18 to the consolidated financial statements included elsewhere in this prospectus for further details on the assumptions used to estimate the fair value of share-based awards granted in prior periods.

JOBS Act

The JOBS Act contains provisions that, among other things, reduce reporting requirements for an “emerging growth company.” As an emerging growth company, we have irrevocably elected to not take advantage of the extended transition period afforded by the JOBS Act for the implementation of new or revised accounting standards. As a result, we will comply with new or revised accounting standards on the relevant dates on which adoption of such standards is required for non-emerging growth companies.

Recent Accounting Pronouncements

A description of recently issued accounting pronouncements that may potentially impact our financial position and results of operations is disclosed in Note 3, “Application of new and revised standards, amendments and interpretations,” to our consolidated financial statements and related notes appearing elsewhere in this prospectus.

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BUSINESS

Overview

We are a clinical-stage oncology-focused biopharmaceutical company based in Singapore developing novel therapeutics for global markets. We target diseases that are both highly prevalent in Asia and orphan indications in the United States and Europe. Our Asia development platform is designed to enable us to accelerate the development of drugs to treat these diseases. Our portfolio is comprised of four product candidates which target: validated growth pathways applied to new patient segments; novel immune checkpoints; and novel cancer metabolic pathways.

Our lead program, varlitinib, is a reversible small molecule pan-HER inhibitor that targets the human epidermal growth factor receptors HER1, HER2 and HER4. Varlitinib is currently being studied in a global pivotal clinical trial for biliary tract cancer for which we expect to report topline data in 2019. Additionally, varlitinib is currently being studied in a China pivotal clinical trial for biliary tract cancer for which we expect to report topline data in late 2018. We are also conducting a global Phase 2/3 clinical trial of varlitinib for gastric cancer for which we expect to report topline Phase 2 data in the second half of 2018.

We focus on cancers, such as gastric cancer and biliary tract cancer, that are orphan diseases in the United States and Europe for which there are few, if any, approved therapies. Although registration trials for orphan diseases may require fewer patients, recruitment for such trials in the United States and Europe is often challenging given the limited availability of suitable patients. Asia offers a unique opportunity to accelerate the development of novel therapies in diseases where either the cancers are more prevalent or the availability of suitable patients is greater.

We have built a development platform centered in Asia that can generate data suitable for submission to regulators in the United States, Europe, China and Japan. The key components of this platform include:

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Our senior management team has extensive experience in global and regional development, regulatory activities and commercialization of drugs and has an aggregate of over 70 years of experience working in Asia. Our Chief Executive Officer, Dr. Carl Firth, was previously New Product Director for China and Regional Business Development and Strategic Planning Director for AstraZeneca plc, or AstraZeneca. Our Chief Medical Officer, Dr. Bertil Lindmark, was previously Global Head of Research and Development at Almirall, S.A., or Almirall, and Global Head of Clinical Development in Respiratory and Inflammation for AstraZeneca. Our Chief Operating Officer, Dr. Mark McHale, was previously Head of Molecular Sciences for Respiratory and Inflammation at AstraZeneca. Our Head of China, Stephen Doyle, was previously a VP in the Specialty Care Business Unit of Boehringer-Ingelheim GmbH in China and VP Oncology of Sanofi S.A. in China. Our scientific advisory board is chaired by Professor Sir David Lane, the discoverer of p53 and Chief Scientist of Singapore’s Agency for Science, Technology and Research, or A*STAR. Our partners include some of the leading global research centers, such as the MD Anderson Cancer Center, the Huntsman Institute, National Taiwan University and Singapore’s National Cancer Centre.

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Our Product Candidates

The following table summarizes our product candidate pipeline:

We hold global rights to all of our product candidates with the exception of ASLAN002, for which Bristol-Myers Squibb Company, or BMS, acquired global rights, and varlitinib, for which Hyundai Pharm Co., Ltd., or Hyundai, acquired rights for South Korea.

Our lead program, varlitinib, is a highly potent, oral, reversible small molecule pan-HER inhibitor. Targeting individual members of the human epidermal growth factor receptor, or HER, family is a well-validated approach to cancer treatment. In some cancers, HER1-selective or HER2-selective agents, such as Herceptin, appear to be effective for a large number of patients, however, in other cancers such as gastric cancer, only a small number of

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patients have tumors driven by a single receptor, such as HER2. We believe there are larger subsets of patients with cancers driven by a combination of HER1, HER2, HER3 and HER4. In a biomarker-driven Phase 2a clinical trial of HER1/HER2 coexpressing gastric cancer patients, we demonstrated that varlitinib could inhibit downstream growth pathways. In other clinical trials, we have demonstrated that varlitinib has activity in biliary tract cancer, where HER family expression is known to be high, as well as in HER2-positive breast cancer and in subsets of colorectal cancer. Following discussions with the United States Food and Drug Administration, or U.S. FDA, and other regulators, we have initiated a global pivotal clinical trial of varlitinib for biliary tract cancer. We believe varlitinib has the potential to be the first targeted therapy approved for biliary tract cancer.

In addition to varlitinib, we have several other product candidates in development. We are developing ASLAN003, an inhibitor of human dihydroorotate dehydrogenase, or DHODH, in AML and are exploring development in other solid tumors where this mechanism has been shown to be relevant. ASLAN003 has the potential to induce differentiation in blast cells and could be applicable in a broad range of AML patients. ASLAN004 is an IL-4/IL-13 receptor antibody, which we believe has the potential to be a best-in-class therapy for severe atopic dermatitis and asthma, due to greater selectivity in binding target cells via the IL-13 receptor. We plan to initiate a Phase 1 clinical trial for ASLAN004 following the submission of an investigational new drug application, or IND, expected in the third quarter of 2018, and plan to seek a global partner for the continued clinical development and potential commercialization of ASLAN004.

Our preclinical portfolio contains several immuno-oncology discovery programs using conventional antibodies and an antibody fragment technology that we have licensed called Modybodies. ASLAN002 is a small molecule inhibitor of cMET and recepteur d’origine nantais, or RON, an immune checkpoint inhibitor, and is currently partnered with BMS.

Our Strategy

Our goal is to become a leader in the development and commercialization of novel therapeutics for global markets, targeting diseases that are both highly prevalent in Asia and orphan indications in the United States and Europe. We plan to leverage our international presence, broad experience in Asia, extensive knowledge of our target diseases and deep local relationships to expedite drug development.

To achieve our goal, we intend to pursue the following strategy:

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Opportunity and Rationale for Drug Development in Asia

Cancer is one of the leading causes of death globally and is rapidly overtaking heart disease in many developed countries to become the number one cause of mortality. In 2015, there were approximately 1.7 million new cases of cancer and 600,000 deaths caused by cancer in the United States, as compared to 4.3 million new cases and 2.8 million deaths in China alone. Historically, there has been more research in cancers common in the United States and Europe, such as breast and lung cancer, than there has been in other cancer types which are more prevalent in Asia. This lack of research has contributed to fewer treatment options for those cancers that are more prevalent in Asia. For example, in 2016 the prevalence of biliary tract cancer was over 200,000 patients in Asia, compared to approximately 12,600 in the United States, and there are no therapies approved to treat this disease. In gastric cancer, the prevalence was over one million in Asia in 2012, but only approximately 32,000 in the United States, and there is only one targeted therapy approved for first-line treatment. For the cancers on which we are focusing, such as biliary tract cancer and gastric cancer, patients typically present with late-stage disease that has already metastasized. These patients are often not eligible for surgery and curative options are limited. Currently, no drugs are approved in the United States for biliary tract cancer, which has a median overall survival of 11.7 months. For gastric cancer, the median overall survival is 11.1 months and only one targeted therapy is approved for first-line use. We have designed our clinical trials to target the patients most likely to respond to our product candidates, which will be a subset of the overall patient population for each targeted indication.

We believe that our Asia development platform and our understanding of cancers that are prevalent in Asia, in particular in our areas of focus in China, Japan, South Korea and Southeast Asia, will enable us to develop drugs for these diseases more efficiently than could be done in the United States and Europe.

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The advantages of developing drugs in Asia are:

Causes for these differences are believed to include both genetic and environmental factors, including diet, levels of socio-economic development, endemic infections and medical practice. For example, the higher prevalence of Helicobacter pylori infections in certain Asian countries including Japan, China and South Korea, as well as the consumption of salty or spicy foods, are believed to be responsible for the higher levels of gastric cancer in these countries. Northern Thailand has the highest incidence of biliary tract cancer globally, where it affects more patients than any other cancer, due to the consumption of a local fish that often contains parasites that reside in the bile duct of its human host. Globally, HCC is the sixth most common cancer and has one of the highest cancer mortality rates. Prevalence in Asia is higher, with China accounting for over 50% of all HCC cases reported worldwide, and is believed to be driven by the higher prevalence of chronic Hepatitis B and C infection.

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Many of the leading research centers and key opinion leaders for Asia prevalent cancers are based in Asia. Key immuno-oncology studies for Asia prevalent cancers have also been led by Asia investigators and led from Asian clinical centers:

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Our Product Candidates

Varlitinib (ASLAN001)

Varlitinib is a highly potent, oral, reversible, small molecule inhibitor of the human epidermal growth factor receptor, or HER, family of receptor tyrosine kinases, or RTKs. Approved drugs that selectively target HER1 (also known as EGFR) or HER2 have been effective in some patients. However, patients may relapse on or may not respond to these therapies because the growth of their cancers is driven by other HER family receptors. Varlitinib targets multiple members of the HER family of receptors and therefore we believe it may be effective in a broader range of tumor types and effective in patients that have progressed on prior HER1-selective or HER2-selective therapies. Following guidance from the U.S. FDA, we initiated a randomized global pivotal clinical trial testing varlitinib in second-line biliary tract cancer. We expect to report topline data for this trial in 2019. We are also testing varlitinib in a single-arm pivotal clinical trial in biliary tract cancer in China for which we expect to report topline data in late 2018.

We licensed varlitinib from Array BioPharma Inc., or Array, in 2011 after successful completion of five Phase 1 clinical trials in a range of solid tumors, which showed activity in breast cancer. Our assessment of varlitinib and understanding of its mechanism of action led us to believe that it would be effective in gastric cancer and that we were well positioned to accelerate the development of varlitinib through our Asia development platform. To date, we have completed four additional Phase 1b clinical trials and two Phase 2 clinical trials for this product candidate. Over 400 patients have been dosed with varlitinib as monotherapy or in combination with other agents. In these clinical trials, varlitinib was well-tolerated in Caucasian and Asian patients. Varlitinib has demonstrated activity in a range of tumor types including biliary tract, gastric, breast and colorectal cancer. In January 2018, we entered into a new license agreement with Array, which replaces and supersedes our previous collaboration and license agreement, pursuant to which we obtained an exclusive, worldwide license to develop, manufacture and commercialize varlitnib for all human and animal therapeutic, diagnostic and prophylactic uses.

We have obtained orphan drug designation from the U.S. FDA for varlitinib in gastric cancer and cholangiocarcinoma, which represents approximately 60% of biliary tract cancer cases. The IND for varlitinib in biliary tract cancer was originally submitted by Array in 2005 and subsequently inactivated in February 2012. The IND for varlitinib in biliary tract cancer was then reactivated on April 21, 2017. We also have obtained orphan drug designation from the Ministry of Food and Drug Safety in South Korea for varlitinib in biliary tract cancer.

Mechanism of Action

Varlitinib targets the HER family of receptors, comprised of four members, HER1, HER2, HER3 and HER4, which is responsible for driving growth in human epithelial cells. These receptors can be mutated or overexpressed in many tumors, which can cause excessive proliferative activity and uncontrolled growth. For instance, HER2 is often overexpressed or amplified in breast cancer. Many of these tumors are dependent on continued HER2 activity for growth and are therefore sensitive to HER2 targeted agents such as Herceptin (trastuzumab). Similarly in gastric cancer, some tumors are HER2 amplified, and thus are reliant on HER2. Patients with these gastric cancers are sensitive to Herceptin, but such patients represent only approximately 15% of all gastric cancer patients. Others may have tumors driven by other HER family members. We believe that in those patients, a pan-HER inhibitor such as varlitinib, which targets HER1, HER2 and HER4, could inhibit proliferation and control tumor growth. HER3 requires active HER1, HER2 or HER4 to function and therefore varlitinib indirectly inhibits HER3.

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Varlitinib has been designed to have favorable properties with low nanomolar, or nM, potency for the HER family. Varlitinib selectively inhibits the HER family and therefore has the potential for fewer off-target effects. It was well-tolerated in the clinic, with reduced gastrointestinal, or GI, toxicity compared to other pan-HER inhibitors.

Varlitinib Mechanism of Action

As a reversible pan-HER inhibitor, varlitinib binds temporarily to the HER family of receptors when the drug concentration is high, but dissociates when the drug concentration falls. Irreversible pan-HER inhibitors bind permanently to the receptor so when they are absorbed in the GI tract, the receptors in the gut epithelium are irreversibly inhibited and prevented from proliferating, which may lead to high rates of diarrhea in patients. In contrast, the gut epithelium of patients taking a reversible inhibitor like varlitinib can proliferate when the local concentration in the gut falls between dosing, which should result in lower frequency and severity of diarrhea. Importantly, we believe the concentration of varlitinib in the tumor remains stable between dosing leading to sustained target inhibition predicted to be in excess of 90%.

Advantages

We believe that varlitinib has the potential to be the first targeted therapy approved for biliary tract cancer and first-line treatment for HER1/HER2 coexpressing gastric cancer. We believe varlitinib has the following potential competitive advantages:

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Gastric Cancer

Market Opportunity

As of 2012, gastric cancer, or cancer of the stomach, was the fifth most common cancer and the third most common cause of cancer death worldwide. Prevalence was highest in Asia with 1.2 million patients, of which approximately 590,000 were in China. There were approximately 30,000 patients in the United States and 190,000 in Europe. The five-year survival rate of gastric cancer is less than 20%.

Most patients with gastric cancer are asymptomatic during the early stages of disease, which delays the initial diagnosis. Accordingly, the majority of patients present with advanced disease at initial diagnosis. Surgical resection is still the primary curative treatment for localized gastric cancer, however less than 50% of patients present with localized disease.

In the metastatic setting, chemotherapy, such as FOLFOX, XELOX, cisplatin/capecitabine or cisplatin/5-FU, is the standard of care, typically a combination of platinum-based therapy and fluorouridine-based therapy. Recent advances have demonstrated the role of the HER family of receptors in driving tumor growth. Herceptin, an anti-HER2 monoclonal antibody, was the first targeted drug in the metastatic setting to have shown benefit in overall survival when combined with standard doublet chemotherapy. However, the benefits of Herceptin are limited to the 15% of gastric cancer patients that overexpress HER2 and provide an increase in median overall survival from 11.1 months to 13.8 months. As a result, we believe a significant unmet medical need exists for other targeted therapies in gastric cancer. We believe that varlitinib could be effective in treating gastric cancer patients whose tumors are not HER2 amplified, but coexpressed HER1 and HER2. While the coexpression of HER1 and HER2 in gastric cancer is not well documented, epidemiological studies of archived gastric tumors conducted by our collaborating institutions in South Korea and Japan suggest that up to 40% of gastric cancer tumors coexpress HER1 and HER2.

Preclinical and Clinical Development

Varlitinib has shown activity in 20 mouse models of lung, breast, gastric, prostate and colorectal cancer. Varlitinib was shown to have superior tumor growth inhibition compared to multiple approved therapies across a variety of modalities in mouse models. In combination with approved standard of care therapies, including capecitabine, varlitinib has demonstrated additive tumor growth inhibition.

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In studies we performed in collaboration with Singapore’s National Cancer Centre, varlitinib has also shown activity in patient derived xenograft, or PDX, mouse models of gastric cancer and HCC. In two gastric cancer PDX models that coexpress HER1 and HER2 but were not HER1 or HER2 amplified, varlitinib demonstrated dose dependent tumor growth inhibition. A western blot analysis of the varlitinib treated tumors revealed potent inhibition of the MAPK and PI3K pathways, known to be important for tumor growth.

Tumor Growth Inhibition in Two Gastric Cancer PDX Models

To determine whether HER1 and HER2 were driving tumor growth in HER1/HER2 coexpressing tumors, we conducted a Phase 2 paired biopsy clinical trial in patients who had failed one or more courses of prior treatment for gastric cancer. Patients were biopsied on day one, dosed with varlitinib monotherapy for 28 days and then biopsied again. Tumor samples were stained by immunohistochemistry to quantify markers of proliferation (MAPK and Ki67) and survival (AKT and TUNEL). Twenty-three patients were recruited in two cohorts: tumors coexpressing HER1 and HER2, and tumors that were HER2-amplified. The data demonstrated that varlitinib treatment led to down regulation of proliferation and upregulation of tumor apoptosis in evaluable patients that were coexpressing HER1/HER2.

Phase 2 Gastric Cancer Biopsy Data

Based on the positive data generated by varlitinib in the gastric cancer PDX models and in the gastric cancer clinical biopsy trial, we are targeting first-line patients coexpressing HER1 and HER2 that are ineligible for Herceptin, due to low HER2 expression levels. These patients are believed to represent approximately 40% of the gastric cancer population.

In August 2017, we initiated a randomized, double-blind, placebo-controlled Phase 2/3 clinical trial in first-line gastric cancer comparing varlitinib/FOLFOX to placebo/FOLFOX. This global trial is being conducted across 32 sites in eight countries in Asia and Europe in patients with tumors coexpressing HER1 and HER2 who are

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ineligible for Herceptin. We expect the Phase 2 portion of the clinical trial to enroll approximately 40 patients and to report topline data in the second half of 2018 with a primary endpoint of percentage change from baseline in tumor size of target lesions at week 12, as assessed by independent central review, or ICR, according to the Response Evaluation Criteria in Solid Tumours (version 1.1), or RECIST. Secondary endpoints are objective response rate, or ORR, progression-free survival, or PFS, time to recurrence, or TTR, duration of response, or DOR, disease control rate, or DCR, and overall survival, or OS. This clinical trial is expected to progress to Phase 3 if the results from the Phase 2 trial meet the primary endpoint that the percentage reduction in tumor size at Week 12 is statistically significant with a one-sided p-value that is less than 0.1. To determine whether data is statistically significant, we use a “p-value,” which represents the probability that random chance could explain the results. The U.S. FDA utilizes the reported statistical measures when evaluating the results of a clinical trial, including statistical significance as measured by p-value as an evidentiary standard of efficacy, to evaluate the reported evidence of a product candidate’s safety and efficacy. If progressed, we expect to enroll approximately 350 additional patients in the Phase 3 portion of the clinical trial with a primary endpoint of overall survival.

Phase 2/3 Gastric Cancer Trial Design (ongoing)

Biliary Tract Cancer

Market Opportunity

Annually, there are approximately 200,000 new cases of biliary tract cancer in Asia, of which up to 145,000 are in China, and approximately 12,600 new cases in the United States. Biliary tract cancer has a five-year survival rate of less than 10% and there has been little improvement in prognosis or treatment outcomes over the last two decades.

Biliary tract cancer consists of intra-hepatic and extra-hepatic cholangiocarcinoma (cancer of the bile duct), cancer of the gall bladder and papilla of Vater (the final portion of the bile duct emptying into the small bowel). Though biliary tract cancer is considered to be a subset of liver cancer, therapies approved for liver cancer are not approved for biliary tract cancer. There are no therapies approved for biliary tract cancer in the United States. Approximately 35% of patients undergo surgical resection, but recurrence is common, with the disease returning in 50% to 60% of patients. Late-stage patients typically receive chemotherapy. In the first-line setting, the doublet combination of gemcitabine and cisplatin is commonly used and has demonstrated a response rate of 26% and overall survival of 11.7 months.

Specific pathways driving biliary tract cancer have not been identified, however recent data from Japan and China show that approximately 70% of biliary tract cancer tumors exhibit HER family overexpression, with HER4 expressed most widely.

Preclinical and Clinical Development

In the ongoing Phase 1b clinical trials of varlitinib in combination with doublet chemotherapy, consisting of platinum plus fluoropyrimidine chemotherapy, 15 biliary tract cancer patients who have had up to two prior treatments have been enrolled to date. Three patients achieved a partial response (20%) and ten (67%) had stable

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disease, corresponding to a disease control rate of 87%. In those patients that responded, all patients had at least 30 weeks of duration of response and tumor growth was controlled even after patients discontinued doublet chemotherapy and continued on varlitinib monotherapy.

Change in Tumor Size in Biliary Tract Cancer Patients from Phase 1b Clinical Trials:

Varlitinib in Combination with Doublet Chemotherapy

Ongoing Clinical Trials

TREETOPP Trial in Second-Line Biliary Tract Cancer

Based on the results in biliary tract cancer from the Phase 1b clinical trials, we met with the U.S. FDA in October 2016 regarding the design of a registration trial and the overall development pathway for varlitinib in this indication. If this registration trial demonstrates a significant effect on overall response rate, varlitinib could be granted accelerated approval subject to a second confirmatory trial being run after approval to demonstrate an improvement in overall survival. TREETOPP is a randomized, double-blind, placebo-controlled clinical trial in second-line biliary tract cancer comparing varlitinib and capecitabine to placebo and capecitabine. This clinical trial is being led by Dr. Milind Javle at the MD Anderson Cancer Center and plans to recruit a total of 120 patients that have progressed on prior chemotherapy treatment, with 60 patients in each arm, from 58 centers in the United States, Europe, China, Japan, Australia and other Asian countries. The co-primary endpoints are ORR and PFS and will be assessed by ICR according to RECIST. The secondary endpoints are OS, DOR, DCR and tumor size percentage change at week 12, as defined by RECIST. In order to maintain an overall one-sided 10% type I error rate for the trial, we plan to use a Hochberg procedure, meaning that the trial would be deemed to have met its primary objective if either endpoint is significant at the one-sided 5% level or if both endpoints are significant at the one-sided 10% significance level. We expect to report topline data from this trial in 2019. If the endpoints are met, we intend to submit a New Drug Application, or NDA, to the U.S. FDA for accelerated approval in second-line biliary tract cancer.

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Pivotal Biliary Tract Cancer Trial Design (ongoing)

China Second-Line Biliary Tract Cancer

Following discussions with CFDA with regard to the registration path in China for varlitinib in biliary tract cancer, we have also initiated a single-arm pivotal clinical trial of varlitinib in combination with capecitabine. We intend to recruit a total of 68 patients whose disease has progressed on prior chemotherapy treatment. The CFDA has agreed that we can seek approval in China if this trial meets its primary endpoint, showing an improvement in ORR. The secondary endpoints are PFS and OS. We expect to report topline data from this trial in late 2018. If the primary endpoint is met, we intend to file for approval in second-line biliary tract cancer in China.

First-Line Biliary Tract Cancer

We have initiated a Phase 1b/2 clinical trial to test the safety, tolerability and efficacy of varlitinib in first-line biliary tract cancer in combination with gemcitabine/cisplatin. In the Phase 1b portion of the clinical trial, increasing doses of varlitinib are combined with chemotherapy to determine the maximum tolerated dose, or MTD, in first-line biliary tract cancer. When the MTD is declared, the clinical trial is expected to progress to Phase 2. The Phase 2 portion of the clinical trial is planned to be a two-arm double-blind placebo-controlled trial, where varlitinib combined with gemcitabine/cisplatin would be compared to a placebo and gemcitabine/cisplatin, with 69 patients per arm. The primary endpoint of this trial is PFS, as assessed by ICR according to RECIST criteria. The secondary endpoints are ORR, DCR, DOR and OS, and all RECIST-based efficacy endpoints will be assessed by ICR. We plan to assess the clinical trial data using the Simon, Wittes and Ellenberg procedure, in order to detect a minimum 10% difference in the primary endpoint of PFS by 24 weeks, and assuming that 25% of patients in the chemotherapy arm will have partial or complete response and that the probability of selecting the best treatment arm is set at 90%. If the Phase 2 clinical trial is successful, the Phase 3 clinical trial would be a 400 patient double-blind placebo-controlled study comparing gemcitabine/cisplatin and varlitinib with gemcitabine/cisplatin and placebo.

Metastatic Breast Cancer

The prevalence of breast cancer in Asia was approximately 2.3 million patients in 2012, while the prevalence in the United States was approximately 1.0 million, of which approximately 5% was metastatic in both cases. Metastatic breast cancer has a five-year survival rate of 26%. Approximately 20% of these patients have tumors with HER2 amplification and will typically receive the anti-HER2 monoclonal antibody therapies Herceptin and pertuzumab in first-line treatment and then ado-trastuzumab emtansine in second-line treatment. In third-line treatment, patients receive the HER1/HER2 small molecule inhibitor lapatinib plus capecitabine. Varlitinib has demonstrated an improved objective response rate and with lower levels of diarrhea compared to lapatinib in a Phase 2 clinical trial.

We have completed a randomized open label Phase 2 clinical trial in HER2 amplified patients who have progressed on Herceptin. The open label clinical trial enrolled 50 patients with two arms comparing varlitinib

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and capecitabine to lapatinib and capecitabine, with a primary endpoint of tumor shrinkage at week 12, as assessed by ICR according to RECIST. Six patients withdrew consent within the first 30 days following enrollment, of which only one patient experienced a grade 4 serious adverse event, which was diarrhea and assessed as being drug-related. One patient died due to liver failure leading to multi-organ failure and sepsis after 11 days on treatment with varlitinib and capecitabine and was reported as “possibly related” to varlitinib because the immediate cause of the patient’s death could not be determined, and therefore, a relationship to varlitinib could not be excluded. These patients were excluded from the subsequent efficacy analysis. For the patients who remained in the clinical trial, the average tumor shrinkage in the varlitinib arm was 36% compared to 18% in the lapatinib arm, with p=0.075, which met the preset statistical criterion for significance for this clinical trial. (For reference, the U.S. FDA would typically require p£0.05 to demonstrate statistical significance in a pivotal clinical trial.) The ORR was 60% for patients in the varlitinib arm compared to 46% for those in the lapatinib arm. Varlitinib and capecitabine was well-tolerated with 12.5% grades 3/4 diarrhea that was controlled on standard doses of loperamide. The incidence of diarrhea observed in the varlitinib and capecitabine arm also compared favorably to an observed incidence of 40% grades 3/4 diarrhea in published data for neratinib, an irreversible pan-HER inhibitor. In addition, the 60% ORR seen with varlitinib and capecitabine is comparable to the 64% ORR seen in neratinib studies. We also have ongoing investigator-led clinical trials in neoadjuvant breast cancer and breast cancer with brain metastasis.

Phase 2 Metastatic Breast Cancer Trial Design (completed)

Safety

Varlitinib has been dosed as monotherapy and in combination with singlet and doublet chemotherapies commonly used in biliary tract, gastric, metastatic breast and colorectal cancer. The maximum tolerated doses varied from 300mg twice daily to 500mg twice daily (BID).

Varlitinib Maximum Tolerated Dose in Phase 1/1b Clinical Trials

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Phase 1b Clinical Trials of Varlitinib in Combination with Doublet Chemotherapy

In a Phase 1b clinical trial of varlitinib in combination with doublet chemotherapy, patients received six cycles of doublet chemotherapy consisting of cisplatin/5-FU, cisplatin/capecitabine, FOLFOX, XELOX combined with varlitinib, followed by varlitinib monotherapy until progression. The ORR was 18% and the DCR was 93%, with several patients with biliary tract, gastric and colorectal cancer demonstrating prolonged stable disease and partial responses. The majority of patients received one or more lines of therapy before entering the clinical trial and were not selected based on biomarker status. Varlitinib was well-tolerated at 300mg BID when combined with doublet chemotherapy, with a manageable side effect profile typical of HER receptor inhibitors including fatigue, diarrhea, nausea, vomiting, increased bilirubin and hand-foot syndrome.

Change in Tumor Size in Phase 1b Clinical Trials:

Varlitinib in Combination with Doublet Chemotherapy

Across all varlitinib clinical trials, the most commonly occurring drug-related adverse events, or AEs, as of December 31, 2017 were fatigue (43% of patients with any grade, 6% with grade 3 or 4), nausea (43% of patients with any grade, 2% with grade 3 or 4) and diarrhea (39% of patients with any grade, 4% with grade 3 or 4). Grade refers to the severity of the AE, with grade 3 indicating a severe or medically significant but not immediately life-threatening AE and grade 4 indicating an AE with potentially life-threatening consequences.

ASLAN003

ASLAN003 is an orally active, potent inhibitor of DHODH that has the potential to be first-in-class in AML. AML is a cancer of the myeloid line of blood cells, characterized primarily by the rapid growth of abnormal white blood cells that build up in the bone marrow and interfere with the production of normal blood cells. We are conducting a Phase 2 clinical trial to develop ASLAN003 in AML and we expect to report interim data from this trial in the second half of 2018. Our plan is to meet with regulatory authorities to discuss expedited regulatory strategies, such as accelerated approval. We are also exploring other solid tumor types where DHODH may be relevant, such as TNBC and HCC.

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We licensed ASLAN003 from Almirall in 2012 after Almirall’s completion of a Phase 1 single ascending dose clinical trial, in which the drug was well-tolerated in healthy volunteers. We then conducted two additional Phase 1 clinical trials, exploring multiple ascending doses and fed/fasted comparison in healthy volunteers. These trials demonstrated that the drug was well-tolerated and plasma concentrations following dosing were similar in Caucasians and Asians.

Mechanism of Action

In cancer, increased levels of adenosine triphosphate, or ATP, and pyrimidines are required for tumor growth and survival. ASLAN003 is an inhibitor of DHODH, which is the enzyme controlling the rate limiting step in the de novo synthesis of pyrimidines. Pyrimidines are nucleotides and are essential building blocks for the production of DNA and RNA in mammalian cells. DHODH is located in the mitochondria and during manufacture of nucleotides it also contributes to the production of ATP. Inhibition of DHODH depletes the intracellular pool of pyrimidines and contributes to lower levels of ATP. This leads to the induction of the tumor suppressor p53, which at high levels of induction triggers apoptosis, or programmed cell death.

In AML, blast cells are unable to differentiate and form granulocytes, such as neutrophils and eosinophils, causing depletion of white blood cells. All-trans retinoic acid, or ATRA, which is approved to treat certain types of AML representing up to 15% of all AML patients, is able to differentiate these AML blast cells. Over 90% of patients with these types of AML experience a complete response and have a five-year survival of 75% when treated with ATRA. In other subsets of AML, DHODH inhibitors have been shown to promote differentiation of these blast cells in vitro, allowing them to turn into granulocytes, which potentially may reverse the condition.

Teriflunomide and leflunomide, which is a prodrug of teriflunomide, are first generation DHODH inhibitors, approved in the United States, Europe and Asia for the treatment of rheumatoid arthritis and multiple sclerosis, respectively. These molecules are less potent inhibitors of DHODH as compared to ASLAN003 and are sufficient to slow the proliferation of inflammatory cells and therefore adequate in chronic inflammatory disorders. However, these molecules have limited use in oncology because the inhibition of tumor growth requires more potent and sustained inhibition of DHODH. Previous efforts to develop high potency DHODH inhibitors for oncology indications were unsuccessful. Candidate drugs had unacceptable levels of toxicity due to off-target binding and would accumulate in the body, requiring up to two years to clear below pharmacologically active levels after dosing was stopped. As a result, development of these inhibitors did not progress. In contrast, ASLAN003 is not chemically related to first generation DHODH inhibitors. ASLAN003 is up to two orders of magnitude more potent at inhibiting DHODH than leflunomide and teriflunomide, and has a half-life of 18 hours, which should allow once daily dosing. We assessed the potency of ASLAN003 using three standard assays: cell free, human primary cell and human whole blood. The table below shows that ASLAN003 is more potent than teriflunomide. The IC₅₀ value is the concentration of the drug required to produce 50% inhibition of response in the assay.

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ASLAN003 Cellular and Biochemical Potency

Advantages

We believe that ASLAN003 has the potential to be a first-in-class DHODH inhibitor in oncology due to the following competitive advantages:

Market Opportunity

AML patients that have failed on standard of care chemotherapy in AML or do not respond to chemotherapy are termed relapsed/refractory, and represent the majority of the total AML population. In 2016, the annual incidence of relapsed/refractory patients is approximately 13,000 patients in the United States, 8,000 in Europe, 5,000 in Japan and 24,000 in China. Survival is age-dependent and survival rates are extremely poor for the elderly. The five-year relative survival rate for AML patients aged 19 years and below is 65%, but declines to 50% for patients aged 20 to 49 years, and the survival rate for patients aged 65 years or older is only 6%.

The first-line treatment for patients with AML is a combination of aggressive chemotherapies. However, elderly patients with AML typically are ineligible for aggressive treatment regiments due to the significant toxicity associated with these therapies. The survival of these patients is usually less than one year. Over the past two decades, many compounds have been evaluated in AML patients, however, only three targeted drugs have been approved. Furthermore, these drugs target relatively small subsets of patients, leaving a significant unmet need.

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Preclinical and Clinical Development

Our Phase 1 single and multiple ascending dose clinical trials of ASLAN003, which were conducted with 95 healthy subjects, demonstrated dose proportional pharmacokinetics and no accumulation in the body. The exposure profile of the drug was highly similar in Asian and Caucasian subjects, and demonstrated stable drug levels in plasma at multiple doses.

After a single 100mg oral dose of ASLAN003, the plasma levels of the drug in Caucasians and Asians were highly similar. ASLAN003 also reached steady state after the second day of dosing and did not accumulate in the body.

ASLAN003 Pharmacokinetic Profile

Single Dose		Multiple Dose

We predict the exposure of ASLAN003 to result in approximately 90% inhibition of DHODH, with 400mg taken once daily, in comparison to the maximum dose of teriflunomide, which leads to only 30% inhibition, as shown in the graph below:

DHODH Binding with ASLAN003 Compared to Teriflunomide

ASLAN003 in AML

In AML, cancerous blast cells fail to differentiate into mature blood cells and do not follow normal processes controlling cell death due to genetic mutations. As a result, the number of blast cells increases to very high levels,

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crowding out normal red and white blood cell production in the bone marrow, which can eventually result in patient death. Normal differentiated blast cells express specific cell surface markers, such as CD11b, and contain granules, which are active compartments inside the cell that store molecules for killing invading pathogens. ASLAN003 has demonstrated the ability to cause differentiation of AML blast cells leading to mature cells that correctly express CD11b and contain active granules.

Data published in 2016 identified inhibition of DHODH as a key mechanism that can trigger differentiation of blast cells in AML. Inhibition of DHODH and the resultant depletion of the pyramidine pool in AML resulted in extensive differentiation in in vitro and in vivo mouse bone marrow transplant models. In preclinical studies, we have demonstrated that ASLAN003 can differentiate AML blast cells in vitro in a variety of AML cell lines: KG-1, MOLM-14 and THP-1.

Differentiation of AML Cell Lines with ASLAN003

The human AML blast cell line, THP-1, demonstrated differentiation when exposed to low doses of ASLAN003 characterized by expression of cell surface markers of normal immune cells, such as CD11b, condensation of the nuclei and formation of active granules that are indicative of normal human white blood cells. Low concentrations of ASLAN003, approximately equivalent to a 50mg once daily dose in patients, led to over 95% upregulation of CD11b which is indicative of differentiation of AML blast cells to granulocytes.

ASLAN003 exposure also resulted in blast cells developing condensed, lobed nuclei, characteristic of normal human granulocytes, and in the appearance of active granules in the cytoplasm, as demonstrated by the reduction of Nitro Blue Tetrazolium, or NBT, a standard assay for granulocytes, as shown below:

Upregulation of CD11b in AML Blast Cell Line THP-1 with ASLAN003		Formation of Active Granules in AML Blast Cell Line THP-1 with ASLAN003

AML Phase 2 Clinical Trial

We have initiated a Phase 2 clinical trial with ASLAN003 in relapsed/refractory AML in Singapore and Australia. We intend to initially recruit 18 patients for this trial and test three doses of ASLAN003 in the AML population as monotherapy for 28 days or until progression with a primary endpoint of the rates of complete remission, or CR, and complete remission with incomplete bone marrow recovery, or CRi, followed by an expansion cohort of an additional 20 patients with the potential to combine with standard induction chemotherapy.

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Potential Development Opportunity for ASLAN003 in Solid Tumors

Recent publications have demonstrated that PTEN mutant cancers and TNBC are particularly sensitive to DHODH inhibition. Additional evidence suggests that DHODH inhibitors may have synergistic efficacy in TNBC in combination with commonly used chemotherapies and CHK1 inhibitors. We are evaluating ASLAN003 efficacy in TNBC and HCC PDX models.

Safety

ASLAN003 has been dosed in 95 healthy subjects and was well-tolerated in single ascending and multiple ascending dosing, or MAD, up to a maximum dose of 400mg once daily. In single ascending, dosing no AEs were observed. In multiple ascending dosing of 53 subjects, the significant majority of AEs were mild to moderate, as summarized in the table below.

Adverse Event Profile of ASLAN003 (MAD)

ASLAN004

ASLAN004 is a fully human monoclonal antibody that targets the IL-13 receptor α1 subunit, or IL-13Rα1. ASLAN004 is currently in pre-clinical development, and we are not aware of any other antibodies in clinical development targeting IL-13Rα1. By targeting IL-13Rα1, ASLAN004 potently inhibits signaling of both interleukin 4, or IL-4, and interleukin 13, or IL-13. IL-4 and IL-13 are central to triggering symptoms of allergy in atopic dermatitis, such as redness and itching of the skin, as well as asthma symptoms such as shortness of breath, wheezing and coughing. Dupilumab is marketed for severe atopic dermatitis and recently completed a successful Phase 3 clinical trial in asthma. As we target the same pathways as dupilumab, we believe ASLAN004 can follow a similar regulatory path. We believe ASLAN004 has the potential to become a first-in-class IL-13Rα1 inhibitor. By targeting IL-13Rα1, a receptor with a narrower cellular distribution than the IL-4 receptor, we believe ASLAN004 has the potential to offer both a lower dose and lower dosing frequency, which are important features for subcutaneous injections, providing greater patient convenience. In addition, ASLAN004 has more selective binding than dupilumab, which we believe could give ASLAN004 a more favorable side effect profile than dupilumab. We expect to initiate a Phase 1 clinical trial for ASLAN004 in the second half of 2018 and plan to continue development in asthma and severe atopic dermatitis. In the future, we may also develop ASLAN004 in other inflammatory indications, such as chronic obstructive pulmonary disorder, or COPD. We licensed worldwide rights for ASLAN004 from CSL Limited, or CSL, in May 2014.

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Mechanism of Action

ASLAN004 is a fully human monoclonal antibody with high affinity binding that inhibits both IL-4 and IL-13 signaling by binding to IL-13Rα1. The cytokines IL-4 and IL-13 are the main drivers of allergic inflammation and have mutually redundant functions. They selectively bind and stimulate the type 2 receptor, which is a complex composed of IL4Rα and IL-13Rα1. Stimulation of the common receptor for IL-4 or IL-13 triggers a signaling cascade that can result in severe atopic dermatitis or asthma. The pivotal role for this pathway in these disease indications has been exemplified by the monoclonal antibody dupilumab which binds to IL-4Rα to block signaling by IL-4 and IL-13. We are not aware of any other monoclonal antibody in development that can inhibit both IL-4 and IL-13 signaling. IL-13Rα1 has a narrower cellular distribution than IL-4Rα. We believe this can offer potential benefits that include both a lower injection volume and dosing frequency than dupilumab, which requires subcutaneous injections every two weeks with a 2 milliliter injection volume. These potential benefits of ASLAN004 would represent meaningful advantages for patient treatment. An additional benefit of ASLAN004 is its lack of binding to the type 1 receptor, which is expressed on a broader range of hematological cell types. We believe that by avoiding inhibition of the type 1 receptor, ASLAN004 may have fewer side effects than dupilumab, which does bind the type 1 receptor.

The figure below demonstrates the binding of ASLAN004 and dupilumab to the type 2 receptor:

IL-4 / IL-13 Receptor Antibody Mechanism of Action

Advantages

We believe that ASLAN004 has the potential to be a best-in-class therapy:

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Market Opportunity

Market Opportunity in Severe Atopic Dermatitis

Atopic dermatitis is the most common dermatological disease, affecting over 200 million patients worldwide, characterized by red inflamed skin and severe daytime and nighttime itching, which can severely impact patients’ quality of life. Up to one-third of adult atopic dermatitis patients are considered moderate-to-severe, for which currently available therapeutics are limited and management is challenging in the majority of cases.

Treatment options have focused on topical therapies. In December 2016, the U.S. FDA granted approval for Eucrisa (developed by Pfizer Inc.), a topical treatment for mild to moderate atopic dermatitis. More recently in March 2017, the U.S. FDA granted approval for dupilumab (developed by Sanofi S.A. and Regeneron Pharmaceuticals, Inc.) for adults with moderate-to-severe atopic dermatitis.

Market Opportunity in Asthma

Asthma affects approximately 300 million patients worldwide. Chronic inflammation of the airway, combined with bronchial hyper-reactivity causes shortness of breath, wheezing and coughing, potentially leading to exacerbations that may result in hospitalization or death. Over 4.5 million severe asthmatics have symptoms which cannot be controlled with conventional therapies, such as bronchodilators or inhaled corticosteroids.

Xolair (anti-IgE) and Nucala (anti-IL5) are the two leading biological therapies by sales. Novel therapies like dupilumab (not yet approved in asthma) are anticipated to compete with biological therapies and inhaled therapies.

Preclinical and Clinical Development

ASLAN004 is a fully human IgG4 monoclonal antibody that specifically binds to the human IL-13Rα1 protein and was originally made using the Medarex mouse technology. The antibody was isolated and optimized to have picomolar binding affinity by CSL Behring, a member of the CSL group of companies.

ASLAN004 is a potent inhibitor of both IL-4 and IL-13 signaling with a binding affinity in the picomolar range for human IL-13Rα1. In in vitro assays, ASLAN004 inhibits the release of mediators that trigger allergic reactions with an IC50 in the low nM range.

We have constructed manufacturing cell lines that deliver a yield of over two grams per liter of therapeutic antibody. ASLAN004 has been successfully manufactured at the 500-liter production scale in accordance with current good manufacturing practices, or cGMP. ASLAN004 has been tested in four-week good laboratory practices, or GLP, compliant toxicology studies in primates.

We expect to initiate a Phase 1 dose escalation clinical trial for ASLAN004 in 2018 in healthy volunteers, followed by a multiple ascending dose Phase 1 trial conducted in severe atopic dermatitis patients. This clinical trial is expected to provide early efficacy data in severe atopic dermatitis, allowing dose selection and an early comparison to currently available standards of care. We plan to initiate a Phase 1 clinical trial for ASLAN004 in asthma following ongoing discussions with our partner, CSL.

Preclinical Pipeline

We have been building an immuno-oncology portfolio to provide a pipeline of innovative drug candidates that could be used as monotherapy or in combination with other drug candidates in our portfolio.

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Competition

Our industry is intensely competitive and subject to rapid and significant technological change. While we believe that our knowledge, experience and scientific resources provide us with competitive advantages, we face substantial competition from major pharmaceutical companies, specialty pharmaceutical companies and biotechnology companies worldwide. Many of our competitors have significantly greater financial, technical and human resources. Small and early-stage companies may also prove to be significant competitors, particularly through collaborative arrangements with large and established companies. As a result, our competitors may discover, develop, license or commercialize products before or more successfully than we do.

We face competition with respect to our current product candidates, and will face competition with respect to future product candidates, from segments of the pharmaceutical, biotechnology and other related sectors, as well as from academic institutions.

The acquisition or licensing of pharmaceutical products is also very competitive. If we seek to acquire or license products, we will face substantial competition from a number of more established companies, some of which have acknowledged strategies to license or acquire products and many of which are bigger than us and have more institutional experience and greater cash flows than we have. These more established companies may have competitive advantages over us, as may other emerging companies taking similar or different approaches to product licenses or acquisitions. In addition, a number of established research-based pharmaceutical and biotechnology companies may acquire products in late stages of development to augment their internal product lines, which may provide those companies with an even greater competitive advantage.

If our product candidates are approved, they may compete with currently marketed drugs and therapies used for treatment of the same indications, and potentially with drug candidates currently in development. The key competitive factors affecting the success of any approved product include its efficacy, safety profile, price, method of administration and level of promotional activity.

Varlitinib

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ASLAN003

ASLAN004

Manufacturing

We do not have internal manufacturing capabilities for small molecules or biological drugs and we do not intend to build or acquire infrastructure for manufacturing our drugs for clinical or commercial supply. All of our clinical supplies are manufactured in accordance with cGMP using high quality contract manufacturing organizations based in the United States, Europe and Asia.

We are currently developing a validated commercial process for the manufacture of varlitinib. We have contracted with two cGMP compliant third-party manufacturers in the United Kingdom and China to manufacture the active pharmaceutical ingredient and final tablet. The first batches of varlitinib for commercial supply are expected to be available in late 2018.

ASLAN has worked with one contract research organization to manufacture ASLAN004 at a 500 liter scale and is currently in the process of selecting a long term commercial manufacturer for this drug. Fill and finish for ASLAN004 is performed by Vetter Pharma International GmbH, or Vetter, in the United States, which is capable of manufacturing final drug product for commercial launch.

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Varlitinib

Varlitinib drug substance is manufactured in accordance with cGMP by Sterling Pharma Solutions Limited in the United Kingdom. We have manufactured at the 200kg scale and are currently in process validation at the 350kg scale. Varlitinib drug product (tablet) is manufactured in accordance with cGMP by PCI Pharma Services in the United Kingdom. Both drug substance and drug product can be scaled to over four tons per year. A second site manufacture for varlitinib in accordance with cGMP has been established at WuXi Apptec Co., Ltd., or WuXi, in China for both drug substance and drug product. Currently, WuXi has successfully manufactured at the 30kg scale.

ASLAN003

ASLAN003 drug substance has been manufactured by Sigma-Aldrich Company LTD in Switzerland at the 30kg scale in accordance with cGMP. ASLAN003 drug product in the form of capsules has been manufactured by WuXi in China in accordance with cGMP. We expect to develop an ASLAN003 tablet in 2018 and plan to conduct further scale up and process optimization.

ASLAN004

Manufacturing cell lines for ASLAN004 were created by Selexis SA in Switzerland. These cell lines deliver over two grams of drug substance per liter. Process development for ASLAN004 was established at JHL Biotech, Inc. and 500 liter manufacture for toxicology and cGMP compliant clinical supply has been completed. Vetter in the United States is responsible for cGMP-compliant fill and finish into glass vials for clinical supply.

License and Collaboration Agreements

License Agreement with Array

On January 3, 2018, we entered into a new license agreement with Array pursuant to which we obtained an exclusive, worldwide license to develop, manufacture and commercialize varlitinib for all human and animal therapeutic, diagnostic and prophylactic uses. This new license agreement replaces and supersedes our previous collaboration and license agreement with Array dated July 12, 2011.

Under the new license agreement, we agreed to use commercially reasonable efforts to obtain approval by the U.S. FDA or the applicable health regulatory authority and commercialize varlitinib.

In consideration of the rights granted to us under the agreement, we made an initial upfront payment to Array of $12 million and are required to make an additional upfront payment between $11 million and $12 million by no later than January 3, 2019, with the specific amount within that range payable depending upon the timing of such payment. In addition, we will be required to pay up to $30 million if certain development milestones are achieved, $20 million if certain regulatory milestones are achieved, and up to $55 million if certain commercial milestones are achieved. We are also required to pay Array tiered royalties in the low tens on net sales of varlitinib. Our royalty obligations will continue on a country-by-country basis through the later of the expiration of the last valid patent claim for varlitinib or ten years after the first commercial sale of varlitinib in a given country.

If within two years of the date of the new license agreement we sublicense varlitinib and are paid an upfront payment, Array will further be entitled to receive one-half of the portion of any such upfront payment that exceeds a specified amount. In the event that the base royalty under a sublicense agreement is 20% or less, we will only be required to share with Array one-half of the amount actually received by us under such sublicense agreement in lieu of the tiered royalties described above, provided that the royalty paid in such case shall in no event be less than a royalty in the high single digit range.

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If we undergo a change in control during a defined period following execution of the new license agreement, Array will also be entitled to receive a low to mid single-digit percentage of the proceeds resulting from the change in control. Unless earlier terminated, the agreement will continue on a country-by-country basis until the expiration of the respective royalty obligations in such country. Upon such expiration in such country, Array will grant to us a perpetual, royalty-free, non-terminable, non-revocable, non-exclusive license to exploit certain know-how in connection with the development, manufacturing and/or commercialization of varlitinib for all human and animal therapeutic, diagnostic and prophylactic uses in such country. Either party may terminate the agreement (i) in the event of the other party’s material breach of the agreement that remains uncured for a specified period of time or (ii) the insolvency of the other party. We may also terminate the agreement without cause at any time upon 180 days advance notice to Array.

Development and License Agreement with Almirall

On May 16, 2012, we entered into a development and license agreement with Almirall, pursuant to which we obtained an exclusive, worldwide license to certain patents, know-how and other intellectual property controlled by Almirall to a DHODH inhibitor, LAS186323, which we refer to as ASLAN003. The licensed field covered by this agreement was limited to the treatment or prevention of rheumatoid arthritis, excluding any topical formulation.

On December 21, 2015, we entered into an amended development and license agreement with Almirall which replaced the previous agreement, further amended by an amendment agreement entered into on March 16, 2018. Under the agreement as so amended, we obtained from Almirall an expanded exclusive, worldwide license to develop, manufacture and commercialize ASLAN003 products for all human diseases with primary focus on oncology diseases, excluding topically-administered products embodying the compound for keratinocyte hyperproliferative disorders, and the non-melanoma skin cancers basal cell carcinoma, squamous cell carcinomas and Gorlin Syndrome, or collectively, the KHD/NMSC products. We generally have the right to sublicense our rights under the agreement. If Almirall wishes to use a third party to develop KHD/NMSC products, we have a right of first negotiation to obtain a license from Almirall to carry out those developments.

Under the amended agreement, we are generally obligated to use commercially reasonable efforts to develop ASLAN003 products in accordance with the development plan, and to commercialize ASLAN003 products, either by ourselves or through sublicensees. We agreed not to develop or commercialize any competing product that has the same mechanism of action as ASLAN003 while the intellectual property licensed from Almirall remains in force or for ten years after the launch of ASLAN003 products on a country-by-country basis, whichever is longer. In addition, we granted to Almirall the right to use certain developed know-how for Almirall’s internal and commercial programs for KHD/NMSC products, and Almirall granted us the right to use certain know-how developed by or on behalf of Armirall in the course of its programs for KHD/NMSC products in the field licensed to ASLAN.

In consideration of the rights granted to us under the amended agreement, we will be required to pay an aggregate of up to $30 million if certain development milestones are achieved and an aggregate of up to $50 million if certain regulatory milestones are achieved, in each case across different indications. If we commercialize any ASLAN003 products, we will be required to pay Almirall tiered royalties in the mid single-digit range on net sales of ASLAN003 products, subject to adjustments in certain circumstances. In the event we sublicense any of our rights under the agreement relating to the ASLAN003 technology, we will be obligated to pay Almirall 10% of sublicensee income we may receive under such sublicenses.

Unless earlier terminated, the amended agreement continues indefinitely. Either party may terminate the agreement (i) in the event of the other party’s material breach of the agreement that remains uncured for a specified period of time, (ii) if significant safety issues arise which make development or commercialization of the product unlawful or in violation of standard industry practices, (iii) if the other party becomes insolvent or (iv) if the continuation of the agreement is no longer commercially viable, as proven by us based on supporting objective data reasonably acceptable to Almirall and us. Almirall may terminate the agreement (i) if we fail to

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provide evidence of having used commercially reasonable efforts to pursue development or commercialization, (ii) if we challenge or assist third parties in challenging any intellectual property rights licensed from Almirall under the amended agreement, (iii) if there is a general withdrawal or recall of ASLAN003 products from any country, on a product-by-product and/or country-by-country basis or (iv) upon a change of control of ASLAN if such change of control could reasonably be expected to lead to an impairment to Almirall, subject to certain conditions. Under the agreement, an impairment in connection with a change of control will only be deemed to occur if Almirall can demonstrate that (i) a competitor of Almirall will control us, (ii) the commercial value of ASLAN003 products may be damaged, (iii) the commercial value of Almirall’s KHD/NMSC products may be adversely affected, (iv) Almirall’s reputation or the reputation of any of Almirall’s products or compounds in the marketplace may be damaged and/or (v) the party that will control us lacks the resources to maximize commercial sales of ASLAN003 products.

License Agreement with CSL

On May 12, 2014, we entered into a license agreement with CSL, pursuant to which we obtained an exclusive, worldwide license to certain patents, know-how and other intellectual property owned or controlled by CSL related to CSL’s anti-IL13 receptor monoclonal antibody, CSL334, which we refer to as ASLAN004, and antigen binding fragments thereof. Under the agreement, we have the exclusive right to develop ASLAN004 products through clinical proof of concept for the treatment, diagnosis or prevention of diseases or conditions in humans. Although we do not have the right to commercialize ASLAN004 products ourselves, we have the right to grant the commercial rights to third parties after we achieve clinical proof of concept subject to certain conditions.

We are obligated to develop ASLAN004 products through clinical proof of concept at our own expense, and we are required to achieve certain development milestones by specified dates.

In consideration of the rights granted to us under the agreement, we are required to pay to CSL a share in the range of 40 to 50 percent of all licensing revenue we receive. We are also responsible for all payments to third-party licensors to CSL, to the extent such obligations relate to our exploitation of the rights licensed under CSL’s agreement with those parties.

The agreement continues until 12 months after the final development milestone date. However, if we have entered into a sublicense granting the right to commercialize ASLAN004 products to a third party before such date, then the agreement will be extended until the expiration or termination of such third-party sublicense.

Either party may terminate the agreement (i) in the event of the other party’s material breach of the agreement that remains uncured for a specified period of time, (ii) under certain circumstances related to the safety of ASLAN004 or (iii) if the other party becomes insolvent. In addition, we may terminate the agreement under certain circumstances related to the development and commercialization of ASLAN004.

In the event that we enter into an agreement with a third party for the commercialization of ASLAN004 products, and such agreement subsequently expires by its terms, the license of CSL patents and know-how granted under the license agreement will become fully paid-up and perpetual as they relate to the agreement with the third party. If the agreement is terminated or expires and CSL subsequently commercializes ASLAN004 products or grants a third party rights to commercialize ASLAN004 products, then CSL will pay us royalties on the net sales of ASLAN004 products or share license revenue with us (whichever is applicable).

Collaboration Agreement with NTU

On October 10, 2016, we entered into a licensing and research collaboration agreement with NTU to develop Modybodies using NTU’s novel antibody fragment technology against three specific immuno-oncology targets that we select. All amounts payable under the agreement will be paid in Singapore dollars, or SG$. To fund the research collaboration, NTU agreed to make certain in-kind contributions, and we agreed to make cash payments of $188,888 (SG$255,000) in the aggregate and an in-kind contribution of $27,400 (SG$37,000).

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We have an exclusive option, under pre-negotiated terms, to obtain global rights to develop and commercialize the Modybodies against the three targets that we select. If we exercise the option, we will be required to pay an upfront fee of $22,222 (SG $30,000). In addition, if we achieve certain development and commercialization milestones with respect to the Modybodies, we will also be required to make various milestone payments of up to $9.4 million (SG$12.8 million) in the aggregate. We will also be required to pay NTU tiered royalties in the single-digit range on the net sales of the Modybodies. We have not exercised this option.

The agreement, as amended, has an 18-month term and will expire in April 2018. Either party may terminate the agreement (i) in the event of the other party’s material breach of the agreement that remains uncured for a specified period of time or (ii) the insolvency or liquidation of the other party. The agreement may also be terminated by either party if the parties cannot agree to proceed with the project at any decision point set out in the project plan, or if the parties cannot find a mutually acceptable replacement if the principal investigator for the project is unable to continue to serve. If we exercise our option to obtain global rights to develop and commercialize the Modybodies against the three targets that we select, then unless earlier terminated, such rights will continue on a country-by-country basis until the later of (i) the last to expire of any NTU patents licensed under the agreement or (ii) 20 years from the date of the first commercial sale of a product covered by any NTU patents licensed under the agreement.

Intellectual Property

Patents

Our commercial success depends in part on our ability to identify, obtain and seek protection for our products, drug candidates and our core technologies employing a combination of patent rights, trade secrets, confidentiality agreements and contractual obligations and to operate without infringing, misappropriating or otherwise violating on the proprietary rights of third parties. It is also important we prevent others from infringing, misappropriating or otherwise violating our proprietary or intellectual property rights.

Our intellectual property strategy is, where appropriate, to file new patent applications on inventions, including improvements to existing products/candidates and processes to improve our competitive edge or to improve business opportunities. We continually assess and refine our intellectual property strategy to endeavor to ensure it is fit for purpose.

Our strategy requires us to license assets from third parties with suitable protection and to identify and seek patent protection for our inventions, when possible. This process is expensive and time consuming and we may not be able to file and prosecute all necessary or desirable patent applications at a reasonable cost, in a timely manner or in all jurisdictions where protection may be commercially advantageous, or we may financially not be able to protect our proprietary rights at all. Despite our efforts to protect our proprietary rights, unauthorized parties may be able to obtain and use information we regard as proprietary. Generally, many therapeutic indications currently being pursued have a focus in Asia markets. Where possible, we seek to file in at least major commercial jurisdictions relevant to the product or technology, however, this is assessed on a case by case basis.

Licensing assets from third parties involves technical and scientific due diligence to assess the opportunity, the strength of the intellectual property protection for the asset and the ability to commercialize the asset. This due diligence is usually conducted over a relatively short period of time. It can be difficult to identify all the issues relevant to the assessment. Failure to identify all the relevant issues can impact negatively on the values of the asset.

The issuance of a patent does not ensure that it is valid or enforceable. Therefore, even if we are issued a patent, it may not be valid or enforceable against third parties. Issued patents may be challenged, narrowed, invalidated or circumvented. In addition, court decisions may introduce uncertainty in the enforceability or scope of patents

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owned by pharmaceutical and biotechnology companies. Thus, any of our patents, including patents that we may rely on to protect our market for approved drugs, may be held invalid or unenforceable by a court of final jurisdiction.

Because patent applications in the United States, Europe and many other jurisdictions are typically not published until 18 months after filing, and because publications of discoveries in scientific literature lag behind actual discoveries, we cannot be certain that we were the first to make the inventions claimed in our issued patents or pending patent applications, or that we were the first to file for protection of the inventions set forth in our patents or patent applications. As a result, we may not be able to obtain or maintain protection for certain inventions. Therefore, the enforceability and scope of our patents in the United States, Europe and in many other jurisdictions cannot be predicted with certainty and, as a result, any patents that we own or license may not provide sufficient protection against competitors. We may not be able to obtain or maintain patent protection from our pending patent applications, from those we may file in the future, or from those we may license from third parties. Moreover, even if we are able to obtain patent protection, such patent protection may be of insufficient scope to achieve our business objectives.

In addition, the issuance of a patent does not give us the right to practice the patented invention. Third parties may have blocking patents that prevent marketing of our products or working our own technology. We endeavor to identify early third party patents and patent applications which may be blocking to a product or technology, to minimize this risk. However, relevant documents may be overlooked or missed, which may in turn impact of the freedom to commercialize the relevant asset.

The term of a patent depends upon the laws of the country in which it is issued. In most jurisdictions, including the United States, Europe, China and Japan, the basic patent term is 20 years from the earliest filing date of a non-provisional patent application. In the United States, Europe and Japan, patents relating to inventions are effective for 20 years, subject to the payment of renewal fees. Some jurisdictions, such as the United States, Europe and Japan provide for up to an additional five years patent term extension for therapeutics products that require marketing approval. The requirements for this supplementary protection are set by the relevant authorities in the given jurisdiction. Products approved before the expiry of the basic patent term may benefit from such a patent term extension. It is our strategy to apply for such supplementary protection, where possible.

In addition to patent protection, statutory provisions in the United States, Europe and other countries may provide a period of clinical data exclusivity which may be followed by an additional period of market exclusivity to compensate for the time required for regulatory approval of our drug products. Once the relevant criteria are satisfied, the protection applies automatically. The length of protection depends on the jurisdiction and may also depend on the type of therapy.

Third parties may seek to market “similar” versions of our approved products. Alternatively, third parties may seek approval to market their own products, similar or otherwise, competitive with our products. We may not be able to block the commercialization of these products, which may erode our commercial position in the market place.

If disputes over intellectual property and other rights that we have licensed or co-own prevent or impair our ability to maintain our current licensing or exclusivity arrangements on acceptable terms, we may be unable to successfully develop and commercialize the affected product candidates. In addition, under certain of our collaboration agreements, our licensors may retain the right to grant non-exclusive licenses to the licensed patents and technology to other academic or research institutions for non-commercial research purposes.

Certain provisions in the agreements under which we currently license intellectual property or technology to and from third parties may be susceptible to multiple interpretations. The resolution of any contract interpretation disagreement that may arise could narrow what we believe to be the scope of our rights to the relevant intellectual property or technology, increase what we believe to be our financial or other obligations under the

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relevant agreement or decrease the third party’s financial or other obligations under the relevant agreement, any of which could have a material adverse effect on our business, financial condition, results of operations and prospects.

Varlitinib

Licensed from Array

On July 12, 2011, we entered into a collaboration and license agreement with Array, relating to Array’s pan-HER inhibitor, ARRY-543, which we refer to as ASLAN001 or varlitinib, pursuant to which we obtained an exclusive, worldwide license to develop products incorporating varlitinib as an active ingredient for the treatment or prevention of any diseases or conditions in humans, pursuant to an agreed development plan, and an exclusive, worldwide license to pursue a commercial licensing program in relation to such products. On January 3, 2018, we entered into a new license agreement with Array, which replaces and supersedes our previous collaboration and license agreement, pursuant to which we obtained an exclusive, worldwide license to develop, manufacture and commercialize varlitnib for all human and animal therapeutic, diagnostic and prophylactic uses.

The basic protection for varlitinib is provided by a family of composition of matter patents. These patents disclose a genus and also explicitly discloses varlitinib (example number 52 in WO2005/016346).

As of December 6, 2017, this family of patents included patents issued in the United States (at least three patents, some relating to intermediates and processes), Australia, Canada, China (at least three patents), Chile, Colombia, Europe, Hong Kong, Indonesia, India, Iceland, Japan, South Korea, Macau, Mexico, Norway, New Zealand, Philippines, Russia, Singapore, Ukraine and South Africa. In addition, as of December 6, 2017, this family of patents included patent applications filed in Argentina, Brazil, Egypt, Taiwan and Venezuela. The scope of the claims may differ in the various countries. The normal expiration of this family of patents is November 2024 in the United States and August 2024 outside the United States, subject to the payment of renewal fees.

The first patent application filed in China was not granted based on a technicality of Chinese practice. Subsequently filed divisional patent applications were granted. If the validity of one or more of the granted divisional patents is challenged then one or more of these patents may ultimately be considered invalid. In China typically branded medicines may still grow their market share, even after patent expiration. This trend along with subsequently filed patent applications and the Chinese data exclusivity provisions may minimize the impact of negative decisions that may be received in respect of one or more of the divisional patents.

Protection for the synthetic process of making varlitinib and a key intermediate in that process may be provided from the family of patents derived from WO2007/059257, filed November 15, 2006. As of December 6, 2017, this family of patents includes issued patents in Australia, Canada, China, Colombia, Europe, Hong Kong, Iceland, Israel, Japan, South Korea, Mexico, Philippines, Singapore, Taiwan, Ukraine and the United States. In addition, as of December 6, 2017, this family of patents included patent applications filed in Brazil, India, Norway and Russia. The scope of the claims may differ in the various countries. The normal expiration of this family of patents is November 2026.

Owned by Us

We are the applicant on a number of pending patents mostly relating to medical uses or combination therapies. These include the following pending patent applications:

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Normal expiration of these patents, if granted, is 2036 or 2037 subject to the payment of renewal fees. It is not clear what claims may be granted, if any, when these patents are pursued at the national and regional phase.

There is one unpublished PCT application and at least four unpublished Singapore priority patent applications relating to use of varlitinib. These patent applications are at an early stage of filing and it is not possible to predict what claims may be ultimately granted, if any from these patent applications.

ASLAN003

Licensed from Almirall

On May 16, 2012, we entered into a development and license agreement with Almirall, pursuant to which we obtained an exclusive, worldwide license to certain patents, know-how and other intellectual property controlled by Almirall to a DHODH inhibitor, LAS186323, which we refer to as ASLAN003. On December 21, 2015, we entered into an amended development and license agreement with Almirall which replaced the previous agreement. This was further amended by an amendment agreement entered into on March 16, 2018. Under the amended agreement as so amended, we obtained from Almirall an expanded exclusive, worldwide license to develop, manufacture and commercialize ASLAN003 products for all human diseases with primary focus on oncology diseases, excluding topically-administered products embodying the compound for keratinocyte hyperproliferative disorders, and the non-melanoma skin cancers basal cell carcinoma, squamous cell carcinomas and Gorlin Syndrome.

The basic compound protection for ASLAN003 is provided by the composition of matter family of patents derived from WO2008/077639. As of December 6, 2017, this family of patents included patents issued in Australia, Canada, China, Europe, Hong Kong, Israel, Japan, Mexico, New Zealand, Nigeria, Russia, South Africa, South Korea, Taiwan, and the United States (two patents). In addition, as of December 6, 2017, this family of patents included patent applications filed in Argentina, Bolivia, Chile, Colombia, Ecuador, Egypt, Norway, Pakistan, Peru, Philippines, Singapore, Thailand, Ukraine, Uruguay, Venezuela and Vietnam. The scope of the claims may differ in different countries. The normal expiration of this family of patents is December 2027, subject to the payment of renewal fees.

Owned by Us

We have four unpublished Singapore priority patent applications related to specific uses of ASLAN003.

ASLAN004

On May 12, 2014, we entered into a license agreement with CSL, pursuant to which we obtained an exclusive, worldwide license to certain patents, know-how and other intellectual property owned or controlled by CSL related to CSL’s anti-IL13 receptor monoclonal antibody, CSL334, which we refer to as ASLAN004, and antigen binding fragments thereof.

The basic compound protection for ASLAN004 is provided by a species (specific sequence) composition of matter family of patents is derived from WO2008/060813, filed October 19, 2007. As of December 6, 2017, this family of patents included patents issued in Australia (two patents), Canada, China, Europe (two patents), Japan (two patents), and the United States (four patents). In addition, as of December 6, 2017, this family of patents included patent applications filed in Hong Kong (two applications). The normal expiration of this family of patents is October 2027, subject to the payment of renewal fees.

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The situation for patent term extensions for biological molecules, such as antibodies, may be more complicated than for small molecules, because generally the original legislation was written with reference to small molecules. Having said that, the period of data exclusivity available in the United States may be 12 years.

We have one unpublished Singapore priority patent application filed in the joint names of ASLAN and CSL, related to a specific therapeutic use for ASLAN004. This application is at an early stage of filing and it is not possible to predict what claims may be ultimately granted. We expect that there will opportunities to file new jointly owned patent applications on aspects of the manufacturing process and ASLAN004 formulation.

Trade Secrets

In addition to patents, we rely upon unpatented trade secrets and know-how and continuing technological innovation to develop and maintain our competitive position. However, trade secrets and know-how can be difficult to protect. We seek to protect our proprietary information, in part, by executing confidentiality agreements with our partners, collaborators, scientific advisors, employees, consultants and other third parties, and invention assignment agreements which are included in the engagement and employment contracts we have with our consultants and employees. The confidentiality agreements we enter into are designed to protect our proprietary information and the agreements or clauses requiring assignment of inventions to us are designed to grant us ownership of technologies that are developed through our relationship with the respective counterparty. We cannot guarantee that we have entered into such agreements with each party that may have or have had access to our trade secrets or proprietary technology and processes or that these agreements will afford us adequate protection of our intellectual property and proprietary information rights. If any of the partners, collaborators, scientific advisors, employees and consultants who are parties to these agreements breaches or violates the terms of any of these agreements or otherwise discloses our proprietary information, we may not have adequate remedies for any such breach or violation, and we could lose our trade secrets as a result. If we are unable to maintain the confidentiality of our trade secrets, our business and competitive position may be harmed.

Trademarks and Domain Names

We conduct our business using the trademark “ASLAN,” “ASLAN PHARMACEUTICALS” and our lion logo, as well as domain names incorporating either or both of these trademarks. “ASLAN PHARMACEUTICALS” has been registered in Singapore. In terms of Chinese character versions of our trademarks, in Taiwan, we have a trade mark registration for: “ .” In China, we have a trademark registration for “ .” We also have a pending application in China to protect the following Chinese character version of the word varlitinib: “ ” (wei li ti ni). We have a portfolio of 20 domain names, which includes: aslanpharma.com, aslanpharma.com.sg, aslanpharma.com.tw, aslanpharma.asia, aslanpharma.org, and aslanpharma.biz.

Government Regulation

The U.S. FDA and comparable regulatory agencies in state and local jurisdictions and in foreign countries impose substantial requirements upon the clinical development, manufacture and marketing of pharmaceutical

products. These agencies and other federal, state and local entities regulate research and development activities and the testing, manufacture, quality control, safety, effectiveness, labeling, storage, packaging, recordkeeping, tracking, approval, import, export, distribution, advertising and promotion of our products.

U.S. Government Regulation of Drug Products

In the United States, the U.S. FDA regulates drugs under the Federal Food, Drug, and Cosmetic Act, or FFDCA, and its implementing regulations. The process of obtaining regulatory approvals and the subsequent compliance with applicable federal, state, local and foreign statutes and regulations requires the expenditure of substantial time and financial resources. Failure to comply with the applicable U.S. requirements at any time during the product development process, approval process or after approval, may subject an applicant to a variety of

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administrative or judicial sanctions, such as the U.S. FDA’s refusal to approve pending NDAs, withdrawal of an approval, imposition of a clinical hold, issuance of warning letters, product recalls, product seizures, total or partial suspension of production or distribution, injunctions, fines, refusals of government contracts, restitution, disgorgement or civil or criminal penalties.

The process required by the U.S. FDA before product candidates may be marketed in the United States generally involves the following:

The testing and approval process requires substantial time, effort and financial resources. Preclinical studies include laboratory evaluation of drug substance chemistry, pharmacology, toxicity and drug product formulation, as well as animal studies to assess potential safety and efficacy. Prior to commencing the first clinical trial with a product candidate, we must submit the results of the preclinical tests and preclinical literature, together with manufacturing information, analytical data and any available clinical data or literature, among other things, to the U.S. FDA as part of an IND. Some preclinical studies may continue even after the IND is submitted. The IND automatically becomes effective 30 days after receipt by the U.S. FDA, unless the U.S. FDA, within the 30-day time period, raises safety concerns or questions about the conduct of the clinical trial by imposing a clinical hold. In such a case, the IND sponsor and the U.S. FDA must resolve any outstanding concerns before the clinical trial can begin. Submission of an IND may not result in U.S. FDA authorization to commence a clinical trial.

Clinical trials involve the administration of the investigational new drug to human subjects under the supervision of qualified investigators in accordance with cGCP requirements. A separate submission to the existing IND must be made for each successive clinical trial conducted during product development, as well as amendments to previously submitted clinical trials. Further, an independent IRB for each study site proposing to conduct the clinical trial must review and approve the plan for any clinical trial, its informed consent form and other communications to study subjects before the clinical trial commences at that site. The IRB must continue to oversee the clinical trial while it is being conducted, including any changes to the study plans.

Regulatory authorities, an IRB or the sponsor may suspend or discontinue a clinical trial at any time on various grounds, including a finding that the subjects are being exposed to an unacceptable health risk, the clinical trial is not being conducted in accordance with the U.S. FDA’s or the IRB’s requirements, if the drug has been

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associated with unexpected serious harm to subjects, or based on evolving business objectives or competitive climate. Some studies also include a data safety monitoring board, which receives special access to unblinded data during the clinical trial and may advise us to halt the clinical trial if it determines that there is an unacceptable safety risk for subjects or other grounds, such as no demonstration of efficacy.

In general, for purposes of NDA approval, human clinical trials are typically conducted in three sequential phases that may overlap.