RISK FACTORS

        Investing in ADSs representing our shares involves a high degree of risk. Before deciding whether to invest, you should carefully consider the risks described below, and all other information contained in this prospectus, including our consolidated financial statements and the related notes included elsewhere in this prospectus. The occurrence of any of the events or developments described below could harm our business, financial condition, results of operations and growth prospects. In such an event, the market price of ADSs representing our shares or our shares could decline and you may lose all or part of your investment.

Risks Related to Our Business

We will need significant amounts of additional new capital to fund our continued development activities.

        As of June 30, 2019, we had CHF 36.8 million of cash and cash equivalents. Our monthly spending levels vary based on new and ongoing development and corporate activities. Currently, on a going concern basis, we expect to be able to finance our operations through at least December 2021, unless we are able to raise new funds. Accordingly, we intend to primarily focus our resources on continuing to investigate dipraglurant, an mGlu5 negative allosteric modulator, for use in Parkinson's disease and dystonia and corporate development activities aimed at securing resources from investors, partners and grant providers to advance our other clinical and preclinical programs, as well as our allosteric modulator discovery platform.

        Our budgeted external costs for the development plans described above and further detailed in "Business" are for the most part based on our initial discussions with contract research organizations and other external suppliers, and we have not entered into any agreements or other arrangements that would establish or guarantee the costs of these programs. There is a risk that these development plans could be more costly than we anticipate, including as a result of unanticipated delays.

        Although we believe that we will have sufficient resources to fund our intended operations through at least December 2021, we cannot assure you of this and our ability to finance our operations and pursue our intended development plans beyond that date which will depend on our ability to generate additional funding through further partnerships or grants and amounts we may raise through further financings such as additional equity offerings. If our development plans are not successful, we may not be able to generate additional funding through partnerships or grants, or raise further financing through equity offerings or otherwise, or we may only be able to do so on terms that are not favorable to our shareholders.

        To the extent that we raise additional capital through the issuance of shares or other securities convertible into shares, our existing shareholders will be diluted. Future issuances of such securities, or the perception that such sales may occur, could adversely affect the trading price of our shares and impair our ability to raise capital through future offerings of shares or other equity securities. No prediction can be made as to the effect, if any, that future sales of shares or the availability of shares for future sales will have on the trading price of our shares.

We cannot guarantee that we will have sufficient funds available in the future to develop and commercialize our current or future drug candidates.

        We have limited sources of revenue and will need substantial additional capital to develop and commercialize our product candidates. We may be unable to raise additional capital when needed, or at all, which would force us to reduce or discontinue operations. We do not expect to realize meaningful revenue from product sales, milestone payments or royalties in the foreseeable future, if at all. Our revenue sources are, and, we believe, will remain, extremely limited until and unless our product candidates are clinically tested, approved for commercialization and successfully marketed. To date, we have primarily financed our operations through the sale of securities, milestone payments from partners

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and grants from foundations and governmental agencies. Our ability to raise additional funds will depend on financial, economic and other factors, many of which are beyond our control. Under Swiss law, shareholders have certain preemptive rights to subscribe for newly issued securities in proportion to the nominal value of shares held. These preemptive rights, unless waived, may cause delays and uncertainties in any future equity offering, including in pricing, number of shares offered and dilutive effects, which discourage investment in our securities. We can provide no assurance that we can obtain access to sufficient funds when needed. If we fail to obtain additional funds at acceptable terms when needed, we may have to delay, reduce or terminate our research and development programs, limit strategic opportunities or be forced to cease operations, which may adversely affect our business, financial condition, results of operations and prospects.

We have a history of net losses and negative cash flows, and we expect that such losses will continue for the foreseeable future and that we may never achieve or maintain profitability.

        Since we began operations in 2002, we have not had product revenue and our expenses have substantially exceeded our revenue, resulting in continuing operating losses and an accumulated deficit of CHF 293.6 million at June 30, 2019. For the six-month period ended June 30, 2019, we incurred a net loss of CHF 7.5 million. These losses have resulted principally from costs incurred in research and development of our drug candidates and general and administrative expense.

        We expect to continue to incur significant operating losses in the foreseeable future, primarily due to the cost of our research and development programs, preclinical studies and clinical trials and the regulatory approval process for drug candidates. The amount of future losses is uncertain and our ability to achieve profitability, if ever, will depend on, among other things, us or partners successfully developing drug candidates, obtaining regulatory approval to market and commercialize drug candidates, manufacturing any approved products on commercially reasonable terms, establishing a sales and marketing organization or suitable third party alternatives for any approved product and raising sufficient funds to finance our activities. If we and/or our partners are unable to develop and commercialize one or more of our drug candidates or if sales revenue from any drug candidate that receives approval is insufficient, we will not achieve profitability, which could have a material adverse effect on our business, financial condition, results of operations and prospects.

We are a development-stage company working with novel approaches to therapeutics, which may not be successful.

        We have devoted our resources to the discovery and development of allosteric modulators for neurological diseases. Since inception, we have focused on building a drug discovery platform, including a knowledge-based library and proprietary biological screening tools as well as a portfolio of drug candidates. Discovery and development of allosteric modulators involves novel approaches to therapeutics. We are subject to the risks of failure inherent in the development of product candidates based on new technologies. There is little precedent for the successful commercialization of products based on our technologies, and there are a number of technological challenges that we must overcome to complete most of our development efforts. If we are not successful in development, it will have a material adverse effect on our business, financial condition, results of operations and prospects.

We have no products on the market and we may never generate revenue from the sale or licensing of product candidates.

        Our ability to achieve and sustain profitability depends on obtaining regulatory approvals for and successfully commercializing our product candidates, either alone or with third parties, such as our partner for ADX71149, Janssen, and our partner for GABA_B PAM, Indivior. Currently, none of our product candidates has been approved for marketing and commercialization or is in Phase 3 trials. We cannot guarantee that any of our product candidates will be successfully tested, approved by the U.S.

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Food and Drug Administration, or FDA, the European Medicines Agency, or EMA, Swissmedic, Swiss Agency for Therapeutic Products, or any other regulatory agency or marketed and commercialized at any time in the foreseeable future or at all. If approval is obtained for a product candidate, we cannot assure you that we will be able to generate or sustain revenue from any sales due to factors such as whether the product is manufactured at a competitive cost or accepted in the market, as well as general and industry-specific local and international economic pressures. With our strategy to focus on allosteric modulator development, these risks continue to be significant and may increase to the extent the space becomes more competitive or less favored in the commercial marketplace. Our focus on rare disease indications with the potential for orphan drug designation limits the size of the patient population for even an approved product, unless approval is expanded for use beyond a particular rare disease. Because of the inherently small patient population for treatment of a rare disease, an approved product with orphan drug designation for which pricing is not approved or accepted in the market at an appropriate level may not generate enough revenue to offset costs of development, manufacturing, marketing and commercialization despite any benefits received from the designation, such as market exclusivity, assistance in clinical trial design, a reduction in user fees or tax credits related to development expense, and our business may be adversely affected.

We have been granted U.S. Orphan Drug Designation for dipraglurant for PD-LID and may seek Orphan Drug Designation for other product candidates, and we may be unable to maintain the benefits associated with Orphan Drug Designation, including the potential for market exclusivity.

        Regulatory authorities in some jurisdictions, including the United States and Europe, may designate drugs and therapeutic biologics for relatively small patient populations as orphan drugs. Under the Orphan Drug Act, the FDA may 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, or a patient population greater than 200,000 in the United States where there is no reasonable expectation that the cost of developing the drug will be recovered from sales in the United States. In the United States, Orphan Drug Designation entitles a party to financial incentives such as opportunities for grant funding toward clinical trial costs, tax advantages and user-fee waivers. In addition, if a product that has Orphan Drug Designation subsequently receives the first FDA approval for the disease for which it has such designation, the product is entitled to orphan drug exclusivity, which means that the FDA may not approve any other applications, including a full NDA, to market the same product for the same indication for seven years, except in limited circumstances, such as a showing of clinical superiority to the product with orphan drug exclusivity or where the manufacturer is unable to assure sufficient product quantity.

        We have obtained Orphan Drug Designation for dipraglurant and if we may be able to obtain Orphan Drug Designation for any of our future product candidates in specific indications, we may not be the first to obtain marketing approval for dipraglurant or any other such product candidates for the orphan-designated indication due to the uncertainties associated with developing pharmaceutical products. In addition, exclusive marketing rights in the United States may be limited if we seek approval for an indication broader than the orphan-designated indication or may be lost if the FDA later determines that the request for designation was materially defective or if the manufacturer is unable to assure sufficient quantities of the product to meet the needs of patients with the rare disease or condition.

        Further, even if we obtain orphan drug exclusivity in the U.S. for a product, that exclusivity may not effectively protect the product from competition because different drugs or therapeutic biologics with different active moieties can be approved for the same condition. Even after an orphan product is approved, the FDA can subsequently approve the same drug or therapeutic biologic with the same active moiety for the same condition if the FDA concludes that the later drug or therapeutic biologic is safer, more effective or makes a major contribution to patient care. In Europe, we could be prevented

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from marketing our products if a similar medicinal product is granted orphan drug designation for the same indications that we are pursuing. Once authorized, with a limited number of exceptions, neither the competent authorities of the EU member states, the EMA, or the European Commission are permitted to accept applications or grant marketing authorization for other similar medicinal products with the same therapeutic indication. Marketing authorization could also be granted to a similar medicinal product with the same orphan indication if the latter product is safer, more effective or otherwise clinically superior to the original orphan medicinal product. Orphan Drug Designation neither shortens the development time or regulatory review time of a drug or therapeutic biologic nor gives the drug or therapeutic biologic any advantage in the regulatory review or approval process. In addition, while we may seek Orphan Drug Designation for our future product candidates, we may never receive such designations.

The future of our business and operations depends on the success of our allosteric modulator development programs, including our most advanced proprietary product candidate, dipraglurant.

        We are substantially dependent on the success of our current lead drug candidate, dipraglurant, which we are developing ourselves. In March 2012, we announced the completion of a Phase 2a clinical trial in the United States and Europe with dipraglurant for the treatment of PD-LID. Though the development so far has produced positive results, further development and commercialization for the treatment of PD-LID or other disease indications may not be successful or may experience additional significant delays and setbacks. For example, we are undertaking significant risk in planning a pivotal development program for dipraglurant for the treatment of PD-LID, without having conducted any additional exploratory clinical trials beyond the Phase 2a proof of concept clinical trial; our last clinical trial of dipraglurant in PD-LID was completed seven years ago and the diagnosis and standard of care for PD-LID may have changed in the interim, including standards for marketing authorization. We believe that a failure to develop our most advanced drug candidates, or to do so in a timely manner, would not only harm those programs but also industry and investor confidence in our other programs and could have a material adverse effect on our business, financial condition, results of operations and prospects.

Our dependence on Janssen to develop and commercialize ADX71149 and Indivior to develop and commercialize GABA_B PAM exposes us to significant risks.

        Our collaboration with Janssen, Indivior and any future partner, may not be scientifically, clinically or commercially successful. We are dependent upon Janssen and Indivior, and may be dependent upon any other partners with which we may collaborate in the future, to perform and fund development activities, including clinical testing, regulatory filings and the manufacture and marketing of products. Under our collaboration and license agreements with our partners, our partners have sole responsibility for the financing and development of selected compounds through preclinical and clinical trials, as well as registration procedures and commercialization, if any, in the United States, Japan, the United Kingdom, Germany, France, Spain and Italy. Our partners have authority over all aspects of the development of selected compounds and may develop or commercialize third-party compounds with a different mechanism of action for identical use. Our role on the joint development committee formed under the collaboration and license agreement is advisory and we do not have authority to determine or veto actions. Our partners may take independent action concerning product development, marketing strategies, manufacturing and supply issues and rights relating to intellectual property. Thus, the success of ADX71149 and GABA_B PAM for the treatment of CNS and related diseases currently depends entirely upon the efforts of Janssen and Indivior, respectively. Janssen and Indivior each have significant discretion in determining the efforts and resources it applies to the development and, if approval is obtained, commercialization and marketing of ADX71149 and GABA_B PAM, respectively. Janssen and Indivior may not be effective in obtaining approvals in their respective fields of use, marketing any approved products or arranging for any necessary sublicense, supply, manufacturing or

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distribution relationships, or our partners may change their strategic focus or pursue alternative technologies in a manner that results in reduced or delayed revenue to us. Our partners have a variety of marketed products and their own corporate objectives may not be consistent with our best interests. Changes of this nature might also occur if our partners are acquired or experience changes in management. In any future disagreement with us, our partners will have significantly greater financial and managerial resources on which to draw. Any disagreement could lead to lengthy and expensive litigation or other dispute resolution proceedings as well as extensive financial and operational consequences to us and have a material adverse effect on our business, financial conditions, results of operations and prospects

Our failure to collaborate successfully with partners may delay, impair or prevent the development or commercialization of our drug candidates.

        Our business strategy requires us to enter into various forms of collaboration arrangements with other companies, licensors or licensees to research, develop and commercialize our drug candidates. We are unlikely to be able to enter into new collaborative arrangements, with respect to the drug candidates we are currently developing internally, until we complete at least the next stage of their respective development activities. We cannot assure you that we will be able to maintain our existing collaborations with Janssen and Indivior, negotiate collaboration arrangements in the future on acceptable terms with first choice partners, if at all, or that any such collaboration arrangements will be successful. To the extent that we are not able to maintain or establish such arrangements, we would be forced to seek alternatives, including undertaking drug development and commercialization activities on our own, which would increase our capital requirements and could require us to limit the scope of some or all of our other research and development activities. Under a collaboration agreement, we are likely to have limited influence over the future development or commercialization of the relevant drug candidates. Such development or commercialization may depend significantly on the efforts and activities of the collaborator. Under the terms of an agreement, a collaborator may have significant discretion in determining the efforts and resources it dedicates to the collaboration, which may change over time depending on the collaborator's overall strategic priorities. The suspension or termination of our collaboration arrangements, the failure of our collaboration arrangements to be successful or the delay in the development or commercialization of drug candidates pursuant to collaborations could have a material adverse effect on our business, financial condition, results of operations and prospects.

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

        We are highly dependent on members of our executive team. The loss of the services of any of them may adversely impact the achievement of our objectives.

        Recruiting and retaining qualified employees, consultants and advisors for our business, including scientific and technical personnel, is also 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 and biotechnology companies and academic institutions for skilled individuals. In addition, failure to succeed in preclinical studies, clinical trials or applications for marketing approval may make it more challenging to recruit and retain qualified personnel. The inability to recruit, or loss of services of certain executives, key employees, consultants or advisors, may impede the progress of our research, development and commercialization objectives and have a material adverse effect on our business, financial condition, results of operations and prospects.

        Furthermore, a number of our key employees reside in California, which in the past has experienced both severe earthquakes and wildfires. Disruptions to the services provided by our

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employees based in California due to earthquakes, wildfires or other natural disasters could delay or disrupt our business and operations.

If third parties on which we depend to conduct our clinical trials do not perform as contractually required, fail to satisfy regulatory or legal requirements or miss expected deadlines, our clinical development programs could be delayed and otherwise adversely affected.

        We rely on third party clinical investigators, contract research organizations, or CROs, clinical data management organizations, medical institutions and consultants to design, conduct, supervise and monitor preclinical studies and clinical trials in relation to our product candidates. Because we rely on third parties and do not have the ability to conduct clinical trials independently, we have less control over the timing, quality and other aspects of clinical trials than we would if we conducted them on our own. These investigators, CROs and consultants are not our employees and we have limited control over the amount of time and resources that they dedicate to our programs. These third parties may have contractual relationships with other entities, some of which may be our competitors, which may draw time and resources from our programs. If we cannot contract with acceptable third parties on commercially reasonable terms, or at all, or if these third parties do not carry out their contractual duties, satisfy legal and regulatory requirements for the conduct of clinical trials or meet expected deadlines, our clinical development program could be delayed or otherwise adversely affected. In all events, we are responsible for ensuring that each of our clinical trials is conducted in accordance with the general investigational plan and protocols for the trial. The FDA requires us to comply with good clinical practices for conducting, recording and reporting the results of clinical trials to assure that data and reported results are credible and accurate and that the rights, integrity and confidentiality of trial participants are protected. Our reliance on third parties that we do not control does not relieve us of these responsibilities and requirements. The third parties with which we contract might not be diligent, careful or timely in conducting our clinical trials, as a result of which the clinical trials could be delayed or unsuccessful. Any such event could have a material adverse effect on our business, financial condition, results of operations and prospects.

Because we rely on third party manufacturing and supply partners, our clinical development supplies and other materials may become limited or interrupted or may not be of satisfactory quantity.

        We rely on third party manufacturing and supply partners for our research and development, preclinical studies and clinical trials. We currently do not have in-house facilities to manufacture our research and development, preclinical and clinical drug supplies. In the event that any of our suppliers, for research and development, or preclinical studies or clinical trials, fail to perform their respective obligations in terms of quality, timing or otherwise, or if our supply of such components or other materials become limited or interrupted for other reasons, we may not be able to develop or market our drug candidates on a timely and cost-competitive basis, if at all, which may have a material adverse effect on our business, financial condition, results of operations and prospects. There can be no assurance that our supply of research and development, preclinical and clinical development drugs and other materials will not be limited, interrupted, restricted in certain geographic regions or of satisfactory quality. If the suppliers that currently manufacture our clinical drug supplies cannot continue to do so, we can provide no assurance that we will be able to obtain alternative components and materials from other manufacturers of acceptable quality, or on terms or in quantities acceptable to us, or that we will not require additional components and other materials to manufacture or use our drug candidates. In addition, suppliers need to meet applicable manufacturing requirements and undergo rigorous facility and process validation tests required by regulatory authorities in order to comply with applicable regulatory standards, such as current Good Manufacturing Practices, or cGMP. We cannot provide assurance that our suppliers will comply with such requirements.

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Our product candidates may not successfully obtain regulatory approval.

        Even if we are able to initiate Phase 3 clinical trials and they are completed, there can be no assurance that we will receive approval from the FDA, the EMA, Swissmedic, Swiss Agency for Therapeutic Products, or any other relevant government agencies. Any approval, if any, may be delayed or may be obtained on restrictive terms. This may occur if a drug candidate does not show acceptable safety and efficacy in preclinical studies and clinical trials or otherwise does not meet applicable regulatory standards for approval or the drug candidate does not prove as effective as, or does not offer therapeutic or other improvements over, existing or future drugs used to treat the same or similar illness or conditions. Failure by us or a partner to obtain approval for products candidates could have a material adverse effect on our business, financial condition, results of operations and prospects.

Our drug candidates must prove their efficacy and safety in rigorous clinical testing that is expensive, time-consuming and may be delayed, suspended or terminated at any time.

        Drug approval requires extensive, time consuming and expensive clinical testing to demonstrate safety, tolerability and efficacy of a drug and meet other regulatory standards for authorization to market and commercialize. The development of innovative drugs is inherently risky and the utility and success of a drug will depend on its efficacy and side effect profile for the target patient population. Preclinical studies and clinical trials are long, expensive and uncertain processes. Successful results obtained in preclinical studies and early clinical trials may not be predictive of results in later clinical trials and do not ensure that later preclinical studies or clinical trials will be successful. Clinical trials may be delayed, suspended or terminated as a result of many factors, many of which are or may be beyond our control, such as:

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suspension or termination of clinical trials by regulators, institutional review boards or data safety monitoring boards;



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termination due to safety issues or lack of efficacy of the drug tested;



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a collaboration partner's termination of an arrangement with us or inadequate dedication of financial or other resources towards development under an arrangement with us;



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inability to enter into adequate collaboration arrangements to complete the development or commercialization and manufacturing of our drug candidates;



•

insufficient availability of a drug product in accordance with cGMP quality; or



•

slower than expected enrollment of patients or lack of compliance by patients.

        We or a partner may be required to conduct clinical trials or other testing of drug candidates beyond those currently contemplated, in particular, if the currently contemplated trials fail to complete successfully or if the results of those trials or tests are negative or inconclusive. It may take us several years to complete this testing, if at all, and failure can occur at any stage of the process, which could delay, increase costs associated with or prevent approval or commercialization of a drug candidate. Even after approval, if any, a drug may be shown to be unsafe or not have its purported effect. As a result, we or a partner may be required to conduct additional trials or studies, be subject to fines, suspension or withdrawal of approval, drug recalls, product seizures, operating restrictions or criminal prosecution. In all such cases, our anticipated development or commercialization timelines may not be met, which could have a material adverse effect on our business, financial condition, results of operations and prospects.

We face competition from entities that have developed or may develop similar or different product candidates aimed at the indications on which we are focusing.

        The development and commercialization of drugs is highly competitive. We compete with a variety of multinational pharmaceutical companies and specialized pharmaceutical companies, including

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products approved for marketing and/or product candidates under development, for each of the product candidates and each of the indications for which we are developing our product candidates. Competitor firms include Adamas Pharmaceuticals, Avanir Pharmaceuticals, Inc., Eli Lilly and Company, F. Hoffmann-La Roche Ltd, Heptares Therapeutics Ltd, Indivior (as certain to product candidates outside the scope of our collaboration with Indivior), Lundbeck Pharmaceuticals Ltd, Medytox Korea Co., Ltd., Merck & Co. Inc., Neuraltus Pharmaceuticals, Inc., Newron Pharmaceuticals, Inc. and Novartis Pharma AG, as well as technology being developed at universities and other research institutions. Many of our competitors have significantly greater financial, technical, manufacturing, marketing, sales and supply resources or experience than we have. Our competitors have developed, are developing or will develop drug candidates and processes that will compete with our drug candidates. Competitors may enjoy a significant competitive advantage if they are able to achieve patent protection, obtain marketing authorizations and commence commercial sales of their drugs before us. Competing drugs could present superior treatment alternatives for our targeted indications, including by being more effective, safer or convenient, and even make our drug candidates or know-how obsolete before we reach the market. In addition, competitors may sell drugs below the price level at which appropriate return for our investment in drug development is possible. As a result of these factors, we may be unable to successfully develop commercially feasible drugs and our commercial opportunities may be reduced or eliminated, and we may not be able to successfully compete. This would have a material adverse effect on our business, financial condition, results of operations and prospects.

We may fail to obtain, maintain or enforce licenses, patents and proprietary technology.

        Our success depends in part on our ability to obtain patent protection for our drug candidates and processes, preserve our trade secrets and other proprietary rights and to defend and enforce our rights against infringement in Europe, the United States and other countries. If we are unable to do so, our drugs, technologies and know-how may not provide us with a competitive advantage. The validity and breadth of claims in patent applications involve complex legal and factual questions and, therefore, involve uncertainty. We own 13 U.S. and 238 foreign patents and a number of pending patent applications that cover various aspects of our technologies. No assurance can be given that patents based on pending patent applications or any future patent applications will be issued. We may need to refine or narrow our claims. Due to their broad scope, some of our generic compound claims may not be patentable. Other of our patent applications may not be granted if third parties have earlier filed applications for inventions covered by our pending patent applications. The scope of any patent protection we are able to obtain may not provide us with sufficient protection against competing drugs or provide competitive advantages to us. Any of the patents that have been or may be issued to us may be held invalid or unenforceable if subsequently challenged by competitors or other third parties. Furthermore, there can be no assurance that others have not developed or will not develop similar drugs, duplicate any of our drugs or design around any patents that have been or may be issued to us. Any of our granted, valid and enforceable patents will provide protection for only a limited period of time. We cannot assure that we will obtain any extensions of patent protection that are sometimes offered if certain clinical development extension application deadlines are met or that we will be successful in seeking any method of use patent. If a method of use patent is granted but product patents are not granted or expire, third parties would be able to develop products using the method in indications not covered by the method of use patent.

We may be restricted in our development and any commercialization activities by third-party patents and patent applications.

        Our commercial success depends on our ability to operate without infringing third-party patents and other intellectual property or market exclusivity rights. If we are not able to do so, we may be subject to infringement actions. We may not be aware of all patents and patent applications that may

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impact our ability to make, use or sell our product candidates. Other parties may have filed, or may file in the future, patent applications covering compounds or drug candidates that are similar to ours. Any such event could have a material adverse effect on our business, financial condition, results of operations and prospects. In addition, because patent applications can take many years to issue and are not published for a period of time ranging on the jurisdictions in which we applied for registration, there may be applications currently pending, unknown to us, which may later result in patents that our drug candidates or technology may infringe. Any conflicts arising from the patent rights of others could significantly reduce the scope of our patents and limit our ability to obtain meaningful patent protection. We may be required to obtain licenses to those patents or to develop or obtain alternative technology. We may not be able to obtain any such licenses on acceptable terms, or at all. Any failure to obtain such licenses could delay or prevent us from pursuing the development or commercialization, if any, of our product candidates.

We may fail to protect our intellectual property rights, including trade secrets and know-how.

        Our success depends on our ability to obtain and enforce intellectual property rights, including trade secrets and non-patentable know-how related to our allosteric modulator platform. We seek to protect or secure this intellectual property, in part, by entering confidentiality agreements with and receiving assignments from our employees, consultants, suppliers, licensees, funding partners and other contractual partners and advisers. We may not always be able to obtain these agreements or assignments. Even if we obtain these agreements or assignments, there can be no assurance that they will effectively protect our intellectual property rights or prevent improper use or disclosure of confidential information or that they will not be breached. We may not have adequate remedies for any breach of these agreements or assignments, or our trade secrets or non-patentable know-how may otherwise become known or be independently developed by competitors. In addition, these agreements or assignments may conflict with, or be subject to, the rights of third parties with which our employees, consultants, suppliers, licensees, funding partners or other contractual partners or advisers had previous employment, consulting or other relationships. Any such event could have a material adverse effect on our business, financial condition, results of operations and prospects.

We may have to defend against or initiate lawsuits to protect our intellectual property rights.

        In the future, third parties with patent claims that overlap with our intended activities may decide to sue us for monetary damages or to prevent us from manufacturing, selling or developing our drug candidates. We could also become subject to claims that we or our employees have inadvertently or otherwise used or disclosed intellectual property, trade secrets or other proprietary information of an employee's former employer, particularly if such employer is a university or pharmaceutical company. Additionally, to protect our patent rights, we may decide to initiate lawsuits against third parties. Defending against or initiating such claims, which typically go on for years before a legal judgment or settlement is obtained, would involve significant effort and expense and could divert management's attention from the operation of our business. Any such proceedings could involve prior art and put our patents at risk of being invalidated or interpreted narrowly and our pending patent applications at risk of not being issued. In addition, there is a risk that some of our confidential information could be compromised by disclosure in such proceedings and provide competitors with access to our proprietary information. Further, the outcome of any such proceedings may be unfavorable to us. If the manufacture, use or sale of any of our drug candidates infringes the patents, or violates other proprietary rights, of third parties, a court or settlement agreement may require us to pay actual damages and, potentially, penalties, including the other party's attorney's fees, which may be substantial. We could also be required to cease the development, manufacture, use and sale of drugs that infringe the patent rights of others, to expend significant resources to redesign our technology so that it does not infringe the patent rights of others, to develop or acquire non-infringing technology, which may not be possible, or to obtain licenses to the infringed intellectual property, which may not

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be available to us on acceptable terms or at all. We cannot guarantee that we will have sufficient financial or other resources to protect intellectual property significant to the development of our product candidates.

Even if a product candidate receives regulatory approval, lack of market acceptance may prevent us from generating revenue from commercialization of the product.

        Even if a product candidate is approved, if we or a partner are not successful in commercializing the product, we will not generate revenue from sales. Revenue generated from an approved product depends on its successful commercialization. Many factors may impede successful commercialization, many of which are or may be beyond our or a partner's control. These factors include the proprietary rights of third parties, including our competitors, the failure of a product to prove effective as, or offer therapeutic or other improvements over, existing or future drugs used to treat the same or similar conditions or the inability of a product to gain acceptance by patients, the medical community or third-party payers, such as insurance companies or government reimbursement programs, or the inability of produce a product in commercial quantities at an acceptable cost, or at all. Even if our drug development is successful and marketing authorization has been obtained, our ability, or our partners' ability, to generate significant revenue will depend on the acceptance of our drugs by physicians, patients, third-party payers and the medical community. We cannot assure you that we or our partners will achieve market acceptance of our drug candidates or generate revenue once we or our partners obtain marketing authorization. The market acceptance of any of our drug candidates depends on a number of factors, including the continued demonstration of efficacy and safety in commercial use, cost-effectiveness, convenience and ease of administration, competition, marketing and distribution support, the scope of the approved uses and labeling requirements, prevalence and severity of any side effects, and adequate government or other third-party coverage or reimbursement for the cost of the drug. To the extent competitors are able to commercialize competing drugs before our drugs have achieved market approval and acceptance, we may have difficulty gaining market acceptance if physicians, patients, third- party payers and the medical community have grown accustomed to use of the competing drugs, whether or not such competing drugs are more effective or have other advantages over our drug.

Any commercialization efforts by us will require us to develop sales, marketing and distribution capabilities internally or through arrangements with third parties.

        Sales, marketing and distribution capabilities are key elements of a successful commercialization strategy, none of which we currently have internally. If any of our product candidates are approved, we intend to market the product either directly or through other strategic alliances and distribution arrangements with third parties. To commercialize our drugs, we will need to enter into new collaborations with third parties or develop our own marketing and sales force with technical expertise and supporting distribution capability. If we decide to market our products directly, we will need to commit significant financial and managerial resources to develop a marketing and sales force with technical expertise and with supporting distribution, administration and compliance capabilities. If we rely on third parties with such capabilities to market our products, we will need to establish and maintain partnership arrangements, and there can be no assurance that we will be able to enter into third-party marketing or distribution arrangements on acceptable terms or at all. To the extent that we do enter into such arrangements, we will be dependent on our marketing and distribution partners. In entering into third-party marketing or distribution arrangements, we expect to incur significant additional expense and there can be no assurance that such third parties will establish adequate sales and distribution capabilities or be successful in gaining market acceptance for our products and services. Any factors preventing or limiting the market acceptance of our drug candidates could have a material adverse effect on our business, financial condition, results of operations and prospects. There can be no assurance that we will be able to build up our own marketing and sales organization, to

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attract and maintain established collaboration partners for the third-party commercialization of our drug candidates, to enter into agreements on acceptable terms for sales and marketing, if at all, or that any such collaboration arrangements will be successful. As a consequence, we would be forced to seek alternatives, redirect our resources or have to limit the scope of our research and development activities in other fields and thereby delay the launch and sales of any or all of our drug candidates, or raise new funds. Accordingly, this could have a material adverse effect on our business, financial condition, results of operations and prospects.

We may become exposed to costly and damaging liability claims and may not be able to maintain sufficient liability insurance to cover these claims.

        Our business with pharmaceutical drugs entails a potential risk of substantial liability for damages, including drug liability and environmental liability, which are inherent in the development, testing and manufacturing of our drug candidates. It is always possible that a drug, even after marketing authorization, may exhibit unforeseen failures or adverse side effects. We can provide no assurance that sufficient insurance coverage will be available to us at acceptable terms, or at all, for any damages or costs in connection with any liability claims. Liability lawsuits are costly and time consuming and may divert management's attention from their normal responsibilities. If any of our drugs were to fail or produce adverse side effects, substantial uninsured losses could result, which could have a material adverse effect on our business, financial condition, results of operations and prospects. Even where drug failures or side effects are not so serious as to warrant withdrawing the drug from the market or liability in damages, they may reduce the drug's competitiveness or adversely affect our reputation, which could have a material adverse effect on our business, financial condition, results of operations and prospects.

We and our partners are subject to significant government regulation, including marketing authorization requirements, which could increase the cost of developing our drug candidates or delay, prevent or limit the commercialization of our drug candidates.

        We and our partners are subject to extensive and rigorous governmental regulation and the applicable regulatory requirements are subject to change. Our and our partner's research and development, preclinical studies and clinical trials, manufacturing, safety, efficacy, record-keeping, labeling, marketing, sales and distribution of our drug candidates are regulated by the EMA, the FDA, Swissmedic, Swiss Agency for Therapeutic Products, and other government agencies in countries where we are testing or intend to test and market our drug candidates. Before a clinical trial can begin, we and our partners must obtain approval from the competent national authority in the country where the trial is planned to be conducted. A favorable opinion from a competent ethics committee or an independent institutional review board on the clinical trial application is also needed. We cannot assure we or our partners will obtain authorization for further testing of drug candidates already in clinical trials or for human clinical trials of any or all of our other candidates currently in research or pre-clinical development. We, and our partners or regulatory authorities may suspend or terminate clinical trials at any time if it is thought that the participants are being exposed to unacceptable health risks. It may take us or our collaborators several years to complete this testing, and failure can occur at any stage of the process.

        The governmental regulation of development of drug candidates extends beyond clinical trials to approvals required for their sale and monitoring after sale, including safety reporting requirements, regulatory oversight of drug promotion and marketing and cGMP. A failure by us or our partners to obtain marketing authorization or a delay in obtaining and maintaining approval could damage our reputation and adversely affect the marketing of our drugs and our ability to generate revenue, which could have a material adverse effect on our business, financial condition, results of operations and prospects. In addition, marketing authorizations, if granted, may not include all uses for which we may seek to market a drug, thereby limiting the potential market for the drug. Moreover, even after

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marketing authorization is obtained, a marketed drug, its manufacturer and its manufacturing facilities are subject to continual review and periodic inspections by the relevant authorities. Consequently, any discovery of previously unknown problems with an approved drug, manufacturer or manufacturing facilities may result in restrictions on the drug or manufacturer, including a requirement to withdraw the drug from the market. In addition, regulatory requirements are evolving in a manner that cannot be predicted. Changes in existing regulations of EMA, FDA, Swissmedic, Swiss Agency for Therapeutic Products or other regulations or the adoption of new regulations could prevent us from obtaining or maintaining, or affect the timing of, future marketing authorizations. Changes in regulatory policy during the period of development of a drug or regulatory review may result in delays or rejections of approvals of the drug candidates. Any change in the regulations governing us could have a material adverse effect on our business, financial condition, results of operations and prospects.

Current healthcare laws and regulations and future legislative or regulatory changes to the healthcare system may affect our ability to sell any drugs we may develop.

        Healthcare laws are subject to change, which may affect our ability to sell any product candidates for which we receive marketing and commercialization approval. In the U.S., an important potential market for our drug candidates, there have been a number of legislative and regulatory changes to the healthcare system that could affect our future results of operations. In particular, there have been and continue to be a number of initiatives at the U.S. federal and state levels that seek to reduce healthcare costs.

        Individual states in the United States have become increasingly aggressive in 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 designed to encourage importation from other countries and bulk purchasing. Legally-mandated price controls on payment amounts by third-party payers or other restrictions could harm our business, results of operations, financial condition and prospects. In addition, regional healthcare authorities and individual hospitals in the United States are increasingly using bidding procedures to determine what pharmaceutical products and which suppliers will be included in their prescription drug and other healthcare programs. This could reduce ultimate demand for our products or put pressure on our product pricing, which could negatively affect our business, results of operations, financial condition and prospects.

        In addition, given recent federal and state government initiatives directed at lowering the total cost of healthcare, Congress and state legislatures will likely continue to focus on healthcare reform, the cost of prescription drugs and biologics and the reform of the Medicare and Medicaid programs. While we cannot predict the full outcome of any such legislation, it may result in decreased reimbursement for drugs and biologics, which may further exacerbate industry-wide pressure to reduce prescription drug prices. This could harm our ability to generate revenue. In addition, legislation has been introduced in Congress that, if enacted, would permit more widespread importation or re-importation of pharmaceutical products from foreign countries into the United States, including from countries where the products are sold at lower prices than we might sell our products in the United States. Such legislation, or similar regulatory changes, could put competitive pressure on our ability to profitably price our products, which, in turn, could adversely affect our business, results of operations, financial condition and prospects. It is also possible that other legislative proposals having similar effects will be adopted.

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Certain European countries utilize reference pricing to control the prices of drugs. Use of reference pricing may increase, which could restrict the sales potential for many new drugs unless the drug can be significantly differentiated from existing drugs.

        Additional governmental and regulatory proposals and health care reforms are possible. However, we are unable to forecast what additional legislation or regulation relating to the health care industry or third-party reimbursement may be enacted in the future, or what effect such legislation or regulation would have on our business. Our business could be harmed by other health care reforms that may be erected or adopted in the future, and in particular this could have a material adverse effect on the amounts that private payers will pay for drugs. As a consequence, we may not be able to realize an appropriate return on our investment in research and development and generate revenue sufficient to attain profitability, even if our drugs are approved for marketing. This could have a material adverse effect on our business, financial condition, results of operations and prospects.

The availability and level of third-party reimbursement for our potential drugs will be uncertain, and it may be difficult to obtain or maintain expected price levels.

        Our or a partner's ability successfully to commercialize our drug candidates and to attract strategic partners for our drug candidates or future drugs will depend in part on price levels and on the extent to which reimbursement for the costs of treatment with these drug candidates will be available from government health administration authorities, private health insurers and other third-party payers, as well as government health care programs. Governments and other third-party payers are increasingly attempting to contain health care costs, in part by challenging the price of medical drugs and services or by restricting the eligibility for reimbursement. Health care cost pressure could lead to pricing pressure which could adversely affect pricing of dipraglurant, ADX71149, GABA_B PAM and our other potential drugs. Seeking third-party reimbursement is a time-consuming and costly process, which will require us and our partners to provide scientific and clinical support for the use of each of our drug candidates to each third-party payer separately. Significant uncertainty exists as to the payment status of newly approved medical drugs. The unavailability or inadequacy of third-party reimbursement, or legislation controlling treatments or prices, could have an adverse effect on the price level and consequently the market acceptance of our drug candidates and may have a material adverse effect on our results or operations, financial condition and prospects.

Any non-compliance by us with the environmental, health and safety laws and regulations that we are subject to could result in fines, suspension of drugs research and development or cessation of our operations or civil liability.

        We are subject to a variety of health, safety and environmental laws and regulations in the jurisdictions in which we operate, particularly in our research and development activities, as well as in our pre-clinical studies. These laws and regulations govern, among other things, the use, storage, handling and discharge or disposal of hazardous materials, chemicals and compounds, including wastewater discharge, air emissions and waste management, where we operate. Our research and development programs involve the controlled use of hazardous materials, chemical and biological materials and controlled pre-clinical animal studies. Although we believe that we hold all permits currently required to operate our business and otherwise comply with current laws and regulations, any failure by us to comply with present or future laws and regulations could result in fines, suspension of research and development or cessation of our operations. We, like many of our competitors, have incurred, and will continue to incur, capital and operating expenditures and other costs in the ordinary course of our business in complying with such laws and regulations in most of the jurisdictions in which we operate. We do not currently anticipate any material additional capital expenditures in respect of such regulations outside of the ordinary course of our business. However, the risk of environmental liability is inherent in our business and there can be no assurance that additional material costs of complying with environmental regulations will not arise in the future. Our research and manufacturing

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activities involve the use of hazardous materials. Although we believe that our safety procedures for handling and disposing of hazardous materials (including medical and biological waste) comply with relevant laws and regulations, we cannot eliminate the risk of accidental or manmade contamination, injury or damage from these materials. In the event of an accident or environmental discharge, we may be held liable for any resulting damages. We cannot assure you that the amount of our insurance coverage will be sufficient to satisfy any such damages. As a result, any such accident could have a material adverse effect on our business, financial condition, results of operation and prospects. In addition, changes to existing or future laws and regulations may result in the imposition on us of significant additional environmental, health and safety compliance costs.

We are exposed to currency fluctuation risks and other financial risks.

        For the six-month period ended June 30, 2019, approximately 38% and 100% of our costs and revenue, respectively, were denominated in currencies other than the Swiss franc. As a result, our business is affected by fluctuations in foreign exchange rates between the Swiss franc and other currencies, particularly U.S. dollars, the Euro and the British pound. A significant amount of our costs are denominated in currencies other than Swiss francs as we source supplies, research and development, consulting and other services in several countries other than Switzerland. On the revenue side, a significant amount relates to currencies other than Swiss francs. The research grants from The Michael J. Fox Foundation for Parkinson's Research are paid in U.S dollars, whereas under our agreement with Janssen, all milestone payments and royalties payable by Janssen to us are denominated in Euros. Furthermore, under our agreement with Indivior, all research funding, milestones payments and royalties payable by Indivior to us are denominated in U.S dollars. Since our reporting currency is the Swiss francs, we convert financial line items into Swiss francs at the applicable foreign exchange rates. As our business grows, we expect that a significant part of our revenue, including milestone payments and royalties, and of our costs, including costs for clinical trials, will be denominated in U.S. dollars, the Euro or the British pound. Unfavorable fluctuations in the value of the Swiss franc compared to these other currencies could have a material adverse effect on our business, financial condition, results of operations and prospects.

Our current operations are concentrated in one location and any events affecting this location may have material adverse consequences.

        Our current operations are located in our facilities situated in Plan-les-Ouates, Geneva, Switzerland. Any unplanned event, such as flood, fire, explosion, earthquake or other accidents that result in us being unable to fully utilize the facilities, may have a material adverse effect on our ability to operate our business, particularly on a daily basis, and have significant negative consequences on our financial and operating conditions. Loss of access to these facilities may result in increased costs, delays in the development of our product candidates or interruption of our business operations. As part of our risk management policy, we maintain insurance coverage at levels we believe are appropriate for our business. However, in the event of an accident at these facilities, we cannot assure you that the amounts of insurance will be sufficient to satisfy any damages and losses. If our facilities are unable to operate because of an accident or for any other reason, even for a short period of time, any or all of our research and development programs may be harmed. Any business interruption may have a material adverse effect on our business, financial position, results of operations and prospects.

We are subject to risks related to data privacy concerns, cyber security breaches and failure to comply with privacy regulations and security requirements relating to data.

        In the ordinary course of our business we come to possess sensitive personal data, including information from clinical trials, and health data obtained in connection with reporting of adverse events. We are subject to data protection laws, privacy requirements and other regulatory restrictions in the various jurisdictions in which we operate.

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        Our failure to keep apprised of, and comply with, privacy, data use and security laws, standards and regulations, including, for instance, unauthorized disclosure of, or access to, data, could result in the suspension or revocation of our approvals or registrations, the limitation, suspension or termination of services or the imposition of administrative, civil or criminal penalties, including fines which may be as high as €20 million or 4% of our annual worldwide revenue (whichever is greater) for serious infringements of the EU General Data Protection Regulation that became effective in May 2018. In addition, we may obtain health information from third parties in the United States (including research institutions from which we may obtain clinical trial data) that are subject to privacy and security requirements under the Health Insurance Portability and Accountability Act of 1996, as amended, or HIPAA. Depending on the facts and circumstances, we could be subject to criminal penalties, including if we knowingly obtain, use, or disclose individually identifiable health information maintained by a HIPAA-covered entity in a manner that is not authorized or permitted by HIPAA. In addition, such failure or non-compliance may cause existing or potential partners, including hospitals, physicians and patients to cease interacting with us, and could damage our reputation and brand. In addition, to the extent more restrictive laws, rules or security requirements relating to business and personal data are adopted in the future in the various jurisdictions in which we operate, such changes could have an adverse impact on our business by increasing our costs or imposing restrictions on our business processes. Accordingly, our failure to keep apprised of, and comply with, privacy, data use and security laws, standards and regulations could have a material adverse effect on our reputation, business, financial condition, results and prospects. Our financial exposure to any actual or alleged breach of such regulations or standards may either not be insured against or not fully covered through our current insurance.

        Cyber security attacks on our servers, information systems and databases, or the third party servers, information systems and databases on which our information is stored, could compromise the security of our data or could cause interruptions in the operations of our businesses. Notwithstanding safeguards, cyber security breaches, internal security breaches, physical security breaches or other unauthorized or accidental access to our servers, other information systems or databases could result in tampering with, or the theft or publication of, sensitive information or the deletion or modification of data, or could otherwise cause interruptions in our operations.

        The tampering with, disruption to, or the theft or publication of, sensitive information or the deletion or modification of records held either in our systems or the systems of others to which we have access, could subject us to increased costs and exposure to litigation. The loss of confidential information could result in the payment of damages and reputational harm and have a material adverse effect on our business, financial condition, results and prospects.

        Our financial exposure from the items referenced above could either not be insured against or not fully covered through any insurance that we maintain and could have a material adverse effect on our business, financial condition, results and prospects.

Risks Related to our ADSs and Shares and our Prospective Nasdaq Listing

An investment in our securities is speculative, and there can be no assurance of any return on any such investment.

        An investment in our securities is highly speculative, and there is no assurance that investors will obtain any return on their investment. Investors will be subject to substantial risks involved in their investment, including the risk of losing their entire investment.

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The market price for our shares and ADSs may be highly volatile and could decline significantly.

        Our securities have a relatively small public float and may be less liquid and more volatile than securities of companies with broader public ownership. Factors affecting the market price of the securities, many of which are beyond our control, include:

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low daily trading volume of our securities on the SIX Swiss Exchange;



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announcements by us and developments that impact our financial results, business and partners;



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fluctuations in our financial position or operating results;



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changes in our business strategy and operations;



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changes in our senior management team or Board of Directors;



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changes in the recommendations of securities analysts regarding us or our industry;



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investor need for liquidity;



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investor assessment of the valuation of us and our competitors;



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fluctuations in interest rates;



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price and volume of the markets where our securities trade; and



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future offerings of our securities.

        In addition, securities markets in general have from time to time, and in particular in recent years, experienced significant price and volume fluctuations. Such fluctuations, as well as the economic environment as a whole, can have a substantial negative effect on the market price of our securities, regardless of our operating results or our financial position. Any such broad market fluctuations may adversely affect the trading price of our securities.

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

        As a company with securities listed in the United States in addition to Switzerland, and particularly after we no longer qualify as an emerging growth company, 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 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.

        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 beginning with our second annual report to be filed with the U.S. Securities and Exchange Commission, or SEC. However, while we remain an emerging growth company, 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, we will need to continue to dedicate internal resources, potentially engage outside consultants and 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

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documented, and implement a continuous reporting and improvement process for internal control over financial reporting. We anticipate that the process to document and evaluate our internal control over financial reporting will be both costly and challenging.

To date, there has been no public market for ADSs representing our shares, and an active market may not develop in which investors can resell such ADSs.

        To date, there has been no public market for ADSs representing our shares although our shares have traded on SIX since 2007. We cannot predict the extent to which an active market for ADSs representing our shares will develop or be sustained after the listing of such securities on Nasdaq, or how the development of such a market might affect the market price for our shares on SIX. The price at which ADSs representing our shares trade on Nasdaq may or may not be correlated with the price at which our shares trade on SIX.

Fluctuations in the exchange rate between the U.S. dollar and the Swiss franc may increase the risk of holding the ADSs.

        Our share price is quoted on SIX in Swiss francs, while the ADSs will trade on Nasdaq in U.S. dollars. Fluctuations in the exchange rate between the U.S. dollar and the Swiss franc may result in temporary differences between the value of the ADSs and the value of our shares, which may result in heavy trading by investors seeking to exploit such differences. In addition, as a result of fluctuations in the exchange rate between the U.S. dollar and the Swiss franc, the U.S. dollar equivalent of the proceeds that a holder of the ADSs would receive upon the sale in Switzerland of any shares withdrawn from the depositary receipts facility, and the U.S. dollar equivalent of any cash dividends paid in Swiss francs on our shares represented by the ADSs, could also decline.

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

        Future sales of a substantial number of ADSs representing our shares or our shares, or the perception that such sales will occur, could cause a decline in the market price of ADSs representing our shares and our shares. As of September 30, 2019, we had 32,848,645 shares issued and outstanding. There were no ADSs representing our shares outstanding as of such date. All of our outstanding shares are freely tradeable on SIX. Upon the effectiveness of the registration statement of which this prospectus forms a part, holders of our shares registered hereby are expected to be able to deposit such shares with the depositary in exchange for ADSs representing such shares at the ratio referred to on the cover page of this prospectus, which ADSs will be freely tradeable. If holders sell substantial amounts of ADSs or shares in the respective public markets therefor, or if the market perceives that such sales may occur, the market price of ADSs representing our shares and our shares and our ability to raise capital through an issue of equity securities in the future could be adversely affected.

We have never paid dividends on our share capital, and we do not anticipate paying cash dividends in the foreseeable future.

        We have never declared or paid cash dividends on our share capital. We do not anticipate paying cash dividends on our registered Shares in the foreseeable future. We currently intend to retain all available funds and any future earnings to fund the development and growth of our business. Any future determination to declare cash dividends will be made at the discretion of our Board of Directors, subject to compliance with applicable laws and covenants under current or future credit facilities, which may restrict or limit our ability to pay dividends and will depend on our financial condition, operating results, capital requirements, distributable profits and/or distributable reserves from capital contributions, general business conditions and other factors that our Board of Directors may

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deem relevant. As a result, capital appreciation, if any, of our securities will be your sole source of gain for the foreseeable future.

The exercise of equity incentive instruments granted under our equity incentive plan could dilute our share capital.

        Pursuant to our existing equity incentive plan, ESCs with subscription rights to purchase shares, employee stock option plan, or ESOP, and warrants may be exercisable at prices below the market price of our shares at the time of exercise. To the extent that these instruments are exercised in the future, holders of our registered shares will be diluted. As of September 30, 2019, there were 11,991,873 shares reserved for issuance pursuant to subscription rights outstanding under our existing equity incentive plan, including 265,600 shares reserved for ESCs, 5,559,375 shares reserved for the ESOP, 5,866,898 shares reserved for warrants, and 1,700 equity sharing certificates.

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

        Except as described in this prospectus, holders of ADSs representing our shares will not be able to exercise voting rights attaching to the underlying shares on an individual basis. Holders of ADSs representing our shares will appoint the depositary or its nominee as their representative to exercise the voting rights attaching to the shares underlying such ADSs. Holders of ADSs representing our shares may not receive voting materials in time to instruct the depositary to vote, and it is possible that holders or persons who hold such ADSs through brokers, dealers or other third parties, will be treated as having instructed the depositary to give a discretionary proxy to the independent proxy holder elected by the Company's shareholders to vote the shares represented by your ADSs. We are permitted to, in certain circumstances, instruct the depository how to rate the shares represented by ADSs that have not been voted. Furthermore, the depositary may not be liable for any failure to carry out any instructions to vote, for the manner in which any vote is cast or for the effect of any such vote. As a result, holders of ADSs representing our shares may not be able to exercise voting rights and may lack recourse if such ADSs are not voted as requested. In addition, holders of ADSs representing our shares will not be able to call a shareholders' meeting.

Holders of ADSs representing our shares may not receive distributions on our shares underlying our ADSs or any value for them if it is illegal or impractical to make them available to such holders.

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

Holders of 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

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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.

ADSs holders may not be entitled to a jury trial with respect to claims arising under the deposit agreement, which could augur less favorable results to the plaintiff(s) in any such action.

        The deposit agreement governing the ADSs representing our shares provides that holders and beneficial owners of ADSs irrevocably waive the right to a trial by jury in any legal proceeding arising out of or relating to the deposit agreement or the ADSs, including claims under federal securities laws, against us or the depositary to the fullest extent permitted by applicable law. If this jury trial waiver provision is prohibited by applicable law, an action could nevertheless proceed under the terms of the deposit agreement with a jury trial. To our knowledge, the enforceability of a jury trial waiver under the federal securities laws has not been finally adjudicated by a federal court. However, we believe that a jury trial waiver provision is generally enforceable under the laws of the State of New York, which govern the deposit agreement, by a court of the State of New York or a federal court, which have non-exclusive jurisdiction over matters arising under the deposit agreement, applying such law. In determining whether to enforce a jury trial waiver provision, New York courts and federal courts will consider whether the visibility of the jury trial waiver provision within the agreement is sufficiently prominent such that a party has knowingly waived any right to trial by jury. We believe that this is the case with respect to the deposit agreement and the ADSs. In addition, New York courts will not enforce a jury trial waiver provision in order to bar a viable setoff or counterclaim sounding in fraud or one which is based upon a creditor's negligence in failing to liquidate collateral upon a guarantor's demand, or in the case of an intentional tort claim (as opposed to a contract dispute), none of which we believe are applicable in the case of the deposit agreement or the ADSs. No condition, stipulation or provision of the deposit agreement or ADSs serves as a waiver by any holder or beneficial owner of ADSs or by us or the depositary of compliance with any provision of the federal securities laws. If you or any other holder or beneficial owner of ADSs brings a claim against us or the depositary in connection with matters arising under the deposit agreement or the ADSs, you or such other holder or beneficial owner may not be entitled to a jury trial with respect to such claims, which may have the effect of limiting and discouraging lawsuits against us and / or the depositary. If a lawsuit is brought against us and / or the depositary under the deposit agreement, it may be heard only by a judge or justice of the applicable trial court, which would be conducted according to different civil procedures and may augur different results than a trial by jury would have had, including results that could be less favorable to the plaintiff(s) in any such action, depending on, among other things, the nature of the claims, the judge or justice hearing such claims, and the venue of the hearing.

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

        We are organized under the law of Switzerland. The rights of holders of shares are governed by the laws of Switzerland and by our Articles of Association. These rights differ in certain respects from the rights of shareholders in typical U.S. corporations. See the sections entitled "Description of Share Capital and Articles of Association—Differences in Corporate Law" and "Description of Share Capital and Articles of Association—Articles of Association—Other Swiss Law Considerations" in this prospectus for a description of the principal differences between the provisions of Swiss law applicable to us and, for example, the Delaware General Corporation Law relating to shareholders' rights and protections.

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Claims of U.S. civil liabilities may not be enforceable against us.

        We are incorporated under the law of Switzerland. Certain of our directors reside outside the United States. As a result, it may not be possible for investors to effect service of process within the United States upon such persons or to enforce judgments obtained in U.S. courts against them or us, including judgments predicated upon the civil liability provisions of the U.S. federal securities laws. The United States and Switzerland do not currently have a treaty providing for recognition and enforcement of judgments (other than arbitration awards) in civil and commercial matters. Consequently, a final judgment for payment given by a court in the United States, whether or not predicated solely upon U.S. securities laws, would not automatically be recognized or enforceable in Switzerland. In addition, uncertainty exists as to whether Swiss courts would entertain original actions brought in Switzerland against us or our directors predicated upon the securities laws of the United States or any state in the United States. Any final and conclusive monetary judgment for a definite sum obtained against us in U.S. courts would be treated by the courts of Switzerland. Whether these requirements are met in respect of a judgment based upon the civil liability provisions of the U.S. securities laws, including whether the award of monetary damages under such laws would constitute a penalty, is an issue for the court making such decision. If a Swiss court gives judgment for the sum payable under a U.S. judgment, the Swiss judgment will be enforceable by methods generally available for this purpose. These methods generally permit the Swiss court discretion to prescribe the manner of enforcement. As a result, U.S. investors may not be able to enforce against us or our certain of our directors, or certain experts named herein who are residents of Switzerland or countries other than the United States, any judgments obtained in U.S. courts in civil and commercial matters, including judgments under the U.S. federal securities laws.

        We are organized under the laws of Switzerland and our jurisdiction of incorporation is Plan-les-Ouates, Geneva, Switzerland. Moreover, a number of our directors and executive officers and a number of directors of each of our subsidiaries are not residents of the United States, and all or a substantial portion of the assets of such persons are located outside the United States. As a result, it may not be possible for investors to effect service of process within the United States upon us or upon such persons or to enforce against them judgments obtained in U.S. courts, including judgments in actions predicated upon the civil liability provisions of the federal securities laws of the United States. We have been advised by our Swiss counsel that there is doubt as to the enforceability in Switzerland of original actions, or in actions for enforcement of judgments of U.S. courts, of civil liabilities to the extent predicated upon the federal and state securities laws of the United States. Original actions against persons in Switzerland based solely upon the U.S. federal or state securities laws are governed, among other things, by the principles set forth in the Swiss Federal Act on International Private Law of 1987, as amended, or PILA. This statute provides that the application of provisions of non-Swiss law by the courts in Switzerland shall be precluded if the result was incompatible with Swiss public policy. Also, mandatory provisions of Swiss law may be applicable regardless of any other law that would otherwise apply.

        Switzerland and the United States do not have a treaty providing for reciprocal recognition of and enforcement of judgments in civil and commercial matters. The recognition and enforcement of a judgment of the courts of the United States in Switzerland is governed by the principles set forth in the PILA. This statute provides in principle that a judgment rendered by a non-Swiss court may be enforced in Switzerland only if:

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the non-Swiss court had jurisdiction pursuant to the PILA;



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the judgment of such non-Swiss court has become final and non-appealable;



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the judgment does not contravene Swiss public policy;

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the court procedures and the service of documents leading to the judgment were in accordance with the due process of law; and



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no proceeding involving the same position and the same subject matter was first brought in Switzerland, or adjudicated in Switzerland, or was earlier adjudicated in a third state and this decision is recognizable in Switzerland.

We currently 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 reporting obligations under the Exchange Act, that, to some extent, are more lenient and less frequent than those of a U.S. domestic public company.

        Upon the effectiveness of the registration statement of which this prospectus forms a part, 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, foreign private issuers are not required to file their annual report on Form 20-F until 120 days 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 and as permitted by the listing requirements of Nasdaq, we may follow Swiss corporate governance rules instead of certain corporate governance requirements of Nasdaq.

        As a foreign private issuer, we may follow our home country corporate governance rules instead of certain corporate governance requirements of Nasdaq. For example, we are exempt from Nasdaq regulations that require a listed U.S. company to:

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have a majority of the board of directors consist of independent directors as such term is defined by Nasdaq;



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have nominating and compensations committees that are fully independent, as defined by Nasdaq;



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solicit proxies and provide proxy statements for all shareholder meetings; and



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seek shareholder approval for the implementation of certain equity compensation plans and issuances of shares.

        For an overview of our corporate governance principles, including those which comply with certain of the requirements above, see the section entitled "Description of Share Capital and Articles of Association—Articles of Association."

        In accordance with our Nasdaq listing, our Audit Committee is required to comply with the provisions of Section 301 of the Sarbanes-Oxley Act of 2002 and Rule 10A-3 of the Exchange Act, both of which also are applicable to Nasdaq-listed U.S. companies.

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        To the extent we determine to follow Swiss corporate governance practices instead of Nasdaq governance requirements applicable to domestic issuers, you may not have the same protections afforded to shareholders of companies that are subject to these Nasdaq requirements.

We may lose our foreign private issuer status, which would then require us to comply with the Exchange Act's domestic reporting regime and Nasdaq's corporate governance requirements applicable to a domestic issuer, and cause us to incur significant incremental legal, accounting and other expenses.

        Although we currently qualify as a foreign private issuer, in order to maintain this status, either (a) a majority of our shares, including shares represented by ADSs, must be either directly or indirectly owned of record by non-residents of the United States or (b)(i) a majority of our executive officers or directors must not be U.S. citizens or residents, (ii) more than 50 percent of our assets must be located outside of the United States and (iii) our business must be administered principally outside of the United States. If we lose our status as a foreign private issuer, we would be required to comply with the Exchange Act reporting and other requirements applicable to U.S. domestic issuers, which are more detailed and extensive than the requirements for foreign private issuers. We would also be required to make changes in our corporate governance practices in accordance with various SEC and Nasdaq rules. The regulatory and compliance costs to us under U.S. securities laws if we are required to comply with the reporting requirements applicable to a U.S. domestic issuer will be significantly higher than the costs that we would incur as a foreign private issuer. As a result, we expect that the loss of foreign private issuer status would increase our legal and financial compliance costs and would make some activities highly time consuming and costly.

We are an "emerging growth company," and we cannot be certain if the reduced reporting requirements applicable to "emerging growth companies" will make ADSs representing our shares or our shares less attractive to investors.

        We are an "emerging growth company" as defined in the JOBS Act. For as long as we continue to be an emerging growth company, we may take advantage of exemptions from various reporting requirements that are applicable to other public companies that are not emerging growth companies, 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 emerging growth company, we are required to report only two years of financial results and selected financial data in this prospectus 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 emerging growth company. We could be an emerging growth company for up to five years, although circumstances could cause us to lose that status earlier, including if the aggregate market value of ADSs representing our shares and our shares held by non-affiliates exceeds $700 million as of any June 30 (the end of our second fiscal quarter) before that time, in which case we would no longer be an emerging growth company as of the following December 31 (our fiscal year-end). We cannot predict if investors will find ADSs representing our shares or our shares less attractive because we may rely on these exemptions. If some investors find such securities less attractive as a result, there may be a less active trading market for ADSs representing our shares or our shares and the price of such securities may be more volatile.

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If we fail to maintain an effective system of internal control 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 ADSs representing our shares or our shares.

        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 ADSs representing our shares or our shares.

        Management will be required to assess the effectiveness of our internal controls annually. However, for as long as we are an "emerging growth company" 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 ADSs representing our shares or our shares and the trading volume thereof could decline.

        The trading market for ADSs representing our shares and our shares will depend in part on the research and reports that securities or industry analysts publish about us or our business. Since we have not undertaken an initial public offering of ADSs representing our shares in connection with the listing of ADSs on Nasdaq, we do not anticipate that many or any industry analysts in the United States will publish such research and reports in the United States about our shares or ADSs. If no or too few securities or industry analysts commence or continue coverage on us, the trading price for ADSs representing our shares and our shares could be affected. If one or more of the analysts who may eventually cover us downgrade such ADSs or shares or publish inaccurate or unfavorable research about our business, the trading price of ADSs representing our shares or our shares would likely decline. If one or more of these analysts cease coverage of us or fail to publish reports on us regularly, demand for ADSs representing our shares or our shares could decrease, which might cause the price of such securities and the trading volume thereof to decline.

If we are a passive foreign investment company, or PFIC, for U.S. federal income tax purposes, the consequences to U.S. holders of our shares or ADSs representing our shares may be adverse.

        Based on our analysis of our income, assets, activities and market capitalization for our taxable year ended December 31, 2018, we believe that we are classified as a "passive foreign investment company," or PFIC, for our taxable year ended December 31, 2018. Based on the expected nature and composition of our income, assets, activities and market capitalization for our taxable year ending December 31, 2019, we anticipate that we may be classified as a PFIC for our taxable year ending December 31, 2019. If we are a PFIC for our taxable year ending December 31, 2019, or any subsequent taxable years, we intend to annually provide U.S. Holders, upon request, a "PFIC Annual

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Information Statement", with the information required to allow U.S. Holders to make a "qualified electing fund" election, or "QEF Election" for United States federal income tax purposes. The application of the PFIC rules is subject to uncertainty in several respects, and therefore, no assurances can be provided with respect to our PFIC status for our taxable year ended December 31, 2018 or with regard to our PFIC status in the past or in the future. Under the Code, a non-U.S. company will be considered a PFIC for any taxable year in which (1) 75% or more of its gross income consists of passive income or (2) 50% or more of the average quarterly value of its assets consists of assets that produce, or are held for the production of, passive income. For purposes of these tests, passive income includes dividends, interest, gains from the sale or exchange of investment property and certain rents and royalties. In addition, 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 and received directly its proportionate share of the income of such other corporation. If we are a PFIC for any taxable year during which a U.S. Holder (as defined below under "Material Income Tax Considerations—Material U.S. Federal Income Tax Considerations for U.S. Holders") holds our shares or ADSs representing our shares, we will continue to be treated as a PFIC with respect to such U.S. Holder in all succeeding years during which the U.S. Holder owns the shares or ADSs representing our shares, regardless of whether we continue to meet the PFIC test described above, unless the U.S. Holder makes a specified election once we cease to be a PFIC. If we are classified as a PFIC for any taxable year during which a U.S. Holder holds our shares or ADSs representing our shares, the U.S. Holder may be subject to adverse tax consequences regardless of whether we continue to qualify as a PFIC, including ineligibility for any preferred tax rates on capital gains or on actual or deemed dividends, interest charges on certain taxes treated as deferred, and additional reporting requirements. For further discussion of the PFIC rules and the adverse U.S. federal income tax consequences in the event we are classified as a PFIC, see the section entitled "Material Income Tax Considerations—Material U.S. Federal Income Tax Considerations For U.S. Holders."

If a United States person is treated as owning at least 10% of our shares, such holder may be subject to adverse U.S. federal income tax consequences.

        If a U.S. Holder is treated as owning, directly, indirectly or constructively, at least 10% of the value or voting power of our shares (directly or in the form of ADSs representing our shares), such U.S. Holder may be treated as a "United States shareholder" with respect to each "controlled foreign corporation" in our corporate group, if any. If such group includes one or more U.S. subsidiaries, certain of our non-U.S. subsidiaries could be treated as controlled foreign corporations, regardless of whether we are treated as a controlled foreign corporation. A United States shareholder of a controlled foreign corporation may be required to annually report and include in its U.S. taxable income its pro rata share of "Subpart F income," "global intangible low-taxed income" and investments in U.S. property by controlled foreign corporations, regardless of whether we make any distributions. An individual that is a United States shareholder with respect to a controlled foreign corporation generally would not be allowed certain tax deductions or foreign tax credits that would be allowed to a United States shareholder that is a U.S. corporation. Failure to comply with these reporting obligations may subject a United States shareholder to significant monetary penalties and may prevent the statute of limitations with respect to such shareholder's U.S. federal income tax return for the year for which reporting was due from starting. We cannot provide any assurances that we will assist our investors in determining whether any of our non-U.S. subsidiaries are treated as a controlled foreign corporation or whether such investor is treated as a United States shareholder with respect to any of such controlled foreign corporations. Further, we cannot provide any assurances that we will furnish to any United States shareholder information that may be necessary to comply with the reporting and tax paying obligations described in this risk factor. U.S. Holders should consult their tax advisors regarding the potential application of these rules to their investment in our shares or ADSs representing our shares.

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Tax authorities may disagree with our positions and conclusions regarding certain tax positions, resulting in unanticipated costs, taxes or non-realization of expected benefits.

        A tax authority may disagree with tax positions that we have taken, which could result in increased tax liabilities. A tax authority could assert that we are subject to tax in a jurisdiction where we believe we have not established a taxable connection, often referred to as a "permanent establishment" under international tax treaties, and such an assertion, if successful, could increase our expected tax liability in one or more jurisdictions. A tax authority may take the position that material income tax liabilities, interest and penalties are payable by us, in which case, we expect that we might contest such assessment. Contesting such an assessment may be lengthy and costly and if we were unsuccessful in disputing the assessment, the result could increase our anticipated effective tax rate.

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