Amylyx Pharmaceuticals Inc (AMLX) Risk Analysis

Our future success depends significantly on our ability to successfully develop, and obtain regulatory approvals for and commercialize, avexitide in PBH and AMX0035 in indications other than ALS, including Wolfram syndrome. Avexitide has been evaluated in five Phase 1 and Phase 2 clinical trials for PBH and has also been studied in congenital HI. In February 2025, we activated the first sites for the pivotal Phase 3 LUCIDITY clinical trial for avexitide in PBH and in April 2025, we announced that the first participant had been dosed. Recruitment and enrollment of LUCIDITY are complete. All participants have been randomized and dosed as of the first quarter of 2026, and we continue to expect topline data in the third quarter of 2026, and if approved, a commercial launch in 2027. We reported positive topline results from the Phase 2 HELIOS trial, an open-label study of AMX0035 in 12 adult participants with Wolfram syndrome. At Week 24, stabilization or improvement was demonstrated across all key clinical measures, including pancreatic function, glycemic control, and vision. Long-term Week 48 data demonstrated that treatment with AMX0035 led to continued sustained stabilization or improvement. At Week 96, measures of pancreatic function and glycemic control were stable or improved relative to baseline in most participants. Visual acuity and patient- and clinician-reported outcomes showed patterns consistent with disease stabilization. Our business success depends heavily on our ability to successfully complete clinical trials for our product candidates. We have completed the IND-enabling studies of AMX0114 in ALS and fully enrolled cohort 1 (n=12) and cohort 2 (n=12) of the Phase 1 LUMINA trial in ALS in September 2025 and March 2026, respectively. We will need to have sufficient funds for, and successfully complete, our clinical development of avexitide in PBH, AMX0035 for the treatment of Wolfram syndrome and other indications, AMX0114 in ALS, AMX0318 in PBH and other rare diseases, and any other product candidates we may develop or acquire. The future regulatory and commercial success of avexitide, AMX0035, AMX0114, AMX0318 or any other current or future product candidates are subject to a number of risks, including the following: - successful completion of preclinical studies and clinical trials;- successful patient enrollment in clinical trials;- positive data from our preclinical studies and clinical trials that supports an acceptable risk-benefit profile of avexitide, AMX0035 or any other current or future product candidates in the intended populations;- satisfaction of applicable regulatory requirements, including to satisfy applicable rules governing fixed dose combination products, as applicable;- the interpretation of our preclinical and clinical data by regulatory authorities to support marketing approvals;- potential unforeseen safety issues or adverse side effects;- receipt and maintenance of marketing approvals from applicable regulatory authorities, including with any expected NCE and new clinical investigation data exclusivity and Orphan Drug market exclusivity, as applicable;- receipt and maintenance of designations from applicable regulatory authorities, including Breakthrough Therapy Designation for avexitide, Orphan Drug Designation for avexitide and AMX0035, and Fast Track Designation for AMX0114;- obtaining and maintaining patent and trade secret protection and regulatory exclusivity for avexitide, AMX0035 or any other current or future product candidates;- making arrangements with third-party manufacturers, or establishing manufacturing capabilities, for both clinical and commercial supplies of avexitide, AMX0035, AMX0114, AMX0318 or any other current or future product candidates;- entry into collaborations to further the development of avexitide, AMX0035, AMX0114, AMX0318 or any other current or future product candidates;- establishing sales, marketing and distribution capabilities and launching commercial sales of our products, if and when approved, whether alone or in collaboration with others;- acceptance of avexitide, AMX0035 or any other products, if and when approved, by patients, the medical community and third-party payors;- appropriately identifying patients with the diseases targeted by avexitide, AMX0035, AMX0114, AMX0318 or any other current or future product candidates and accurately estimating the size of applicable patient populations or disease prevalence;- obtaining and maintaining third-party coverage and adequate reimbursement;- maintaining a continued acceptable safety profile of products following any approval;- effectively competing with other drugs or therapies;- ensuring that we promote and distribute our products consistent with all applicable healthcare laws; and - enforcing and defending intellectual property rights and claims. Many of these risks are beyond our control, including the risks related to clinical development, the regulatory submission process, potential threats to our intellectual property rights and the manufacturing, marketing and sales efforts of any future collaborator. If we are unable to develop, obtain or maintain regulatory approvals for, or successfully commercialize avexitide, AMX0035 or any of our other current or future product candidates, or if we experience delays as a result of any of these risks or otherwise, our business could be materially harmed. In addition, of the large number of drugs in development in the pharmaceutical industry, only a small percentage result in the submission of marketing applications to regulatory authorities, and even fewer are approved for commercialization. Furthermore, even if we do receive regulatory approval for our current or any of our future product candidates, any such approval may be subject to limitations on the indications or uses or the patient populations for which we may market the product. For example, our Phase 3 avexitide trial is in PBH following RYGB surgery, and the FDA may require that we provide additional clinical data to support an indication beyond PBH following RYGB surgery. Additionally, it is unknown whether disruptions and personnel turnover at the FDA, as a result of leadership changes, staff reductions or otherwise, may contribute to uncertainty in the regulatory approval process. Additionally, we may not realize the full commercial potential of avexitide, AMX0035 or any other current or future product candidates that receive marketing approval if we are unable to appropriately identify patients with the diseases targeted by such product candidates. Accordingly, even if we are able to obtain the requisite financing to continue to fund our development activities, we cannot assure you that we will successfully develop or commercialize our current or any future product candidates for any indication in any jurisdiction. If we or any of our future collaborators are unable to develop, maintain, or obtain regulatory approvals for, or, if approved, successfully commercialize our current or any future product candidates for our initial or potential additional indications, we may not be able to generate sufficient revenue to continue our business. In addition, our failure to demonstrate positive results in our clinical trials in any indication for which we are developing our current product candidates, or to satisfy other regulatory requirements, could adversely affect our development efforts for avexitide, AMX0035 in other indications, AMX0114, or AMX0318.

The results of preclinical studies may not be predictive of the results of clinical trials, and the results of any early-stage clinical trials we commence may not be predictive of the results of the later-stage clinical trials. In addition, initial data in clinical trials may not be indicative of results obtained when such trials are completed. There can be no assurance that any of our clinical trials will ultimately be successful or support further clinical development of avexitide, AMX0035, AMX0114, AMX0318 or any other current or future product candidates. For example, the clinical results seen in the CENTAUR trial were different than the results seen in our global Phase 3 PHOENIX clinical trial. There is a high failure rate for drugs and biologics proceeding through clinical trials. A number of companies in the pharmaceutical and biotechnology industries have suffered significant setbacks in clinical development even after achieving promising results in earlier studies, and any such setbacks in our clinical development could have a material adverse effect on our business and operating results. Additionally, we have in the past utilized and may in the future utilize an "open-label" clinical trial design. An "open-label" clinical trial is one where both the patient and investigator know whether the patient is receiving the investigational product candidate or either an existing approved drug or placebo. Most open-label clinical trials test only the investigational product candidate and sometimes may do so at different dose levels. Open-label clinical trials are subject to various limitations that may exaggerate any therapeutic effect as patients in open-label clinical trials are aware when they are receiving treatment. Open-label clinical trials may be subject to a "patient bias" where patients perceive their symptoms to have improved merely due to their awareness of receiving an experimental treatment. In addition, open-label clinical trials may be subject to an "investigator bias" where those assessing and reviewing the physiological outcomes of the clinical trials are aware of which patients have received treatment and may interpret the information of the treated group more favorably given this knowledge. The results from an open-label trial may not be predictive of future clinical trial results with avexitide, AMX0035 or any future product candidates when studied in a controlled environment with a placebo or active control.

From time to time, we may publish interim topline or preliminary data from our clinical trials. Interim data from clinical trials that we may complete are subject to the risk that one or more of the clinical outcomes may materially change as patient enrollment continues and more patient data become available. Preliminary or topline results also remain subject to audit and verification procedures that may result in the final data being materially different from the preliminary data we previously published. As a result, interim and preliminary data should be viewed with caution until the final data are available. Adverse differences between preliminary or interim data and final data could significantly harm our reputation and business prospects.

Patient enrollment is a significant factor in the timing of clinical trials, and the timing of our clinical trials depends, in part, on the speed at which we can recruit patients to participate in our trials, as well as completion of required follow-up periods. We may not be able to initiate or continue clinical trials for avexitide, AMX0035, AMX0114, AMX0318 or any other current or future product candidates if we are unable to locate and enroll a sufficient number of eligible patients to participate in these trials to such trial's conclusion as required by the FDA or other comparable foreign regulatory authorities. Additionally, certain clinical trials for avexitide, AMX0035, AMX0114 and any other current or future product candidates may be focused on indications with relatively small patient populations, which may further limit enrollment of eligible patients or may result in slower enrollment than we anticipate. The eligibility criteria of our clinical trials, once established, may further limit the pool of available trial participants. For example, the number of patients suffering from Wolfram syndrome and/or PBH is small and, in some cases, has not been established with precision. If the actual number of patients with these diseases is smaller than we anticipate, we may encounter difficulties in enrolling patients in our clinical trials, thereby delaying or preventing development and approval of avexitide, AMX0035, AMX0114, AMX0318 or any other current or future product candidates. Even once enrolled, we may be unable to retain a sufficient number of patients to complete any of our trials. Neurodegenerative diseases have particular challenges, including significant mobility issues, morbidities and other complications that have historically made retention in clinical trials more challenging. In the past, we have had discontinuations in our clinical trials, including in our CENTAUR trial and our PHOENIX trial, and their open-label extensions. Discontinuations may occur in current or future trials and could result in delays of completion of our clinical trials and affect our ability to enroll additional patients in our clinical trials and impact the integrity of data from our clinical trials. Patient enrollment and retention in clinical trials depends on many factors, including the size of the patient population, the severity of the disease under investigation, the nature of the trial protocol, the existing body of safety and efficacy data for the product candidate, the number and nature of competing treatments and ongoing clinical trials of or expanded access to competing therapies for the same indication, the proximity of patients to clinical sites, the eligibility criteria for the trial, the ability to adequately monitor patients during a trial, clinicians' and patients' perceptions as to the potential advantages of the product candidate being studied, and the risk that patients will drop out of a trial before completing all site visits. There are limited patient pools from which to draw in order to complete our clinical trials in a timely and cost-effective manner, including due to the fact that the diseases we target are rare. Moreover, for example, the patient population for PBH may decrease due to the development of novel treatments for obesity, reducing the potential need for bariatric surgery. Furthermore, our efforts to build relationships with patient communities may not succeed, which could result in delays in patient enrollment in our clinical trials. Any negative results we may report in clinical trials of avexitide, AMX0035, AMX0114, AMX0318 or any future product candidate may also make it difficult or impossible to recruit and retain patients in other clinical trials of that same product candidate. For example, the PHOENIX trial did not meet its primary or secondary endpoints, which may discourage patients from participating in clinical trials of AMX0035 in other indications. Delays or failures in planned patient enrollment or retention may result in increased costs, program delays or both, which could have a harmful effect on our ability to develop AMX0035 in Wolfram syndrome and additional indications, avexitide and any other current or future product candidates, or could render further development impossible. Further, if patients drop out of our clinical trials, miss scheduled doses or follow-up visits, or otherwise fail to follow clinical trial protocols, whether as a result of public health epidemics and related illness, the integrity of data from our clinical trials may be compromised or not accepted by the FDA or other regulatory authorities, which would represent a significant setback for the applicable program. In addition, we may rely on CROs and clinical trial sites to ensure proper and timely conduct of our future clinical trials and, while we intend to enter into agreements governing their services, we will be limited in our ability to compel their actual performance.

We are currently, and plan to continue, developing and evaluating avexitide and evaluating AMX0035 in other indications other than ALS, and planning to continue to develop other product candidates. We intend to evaluate internal opportunities from avexitide, AMX0035 or other potential product candidates, and also may choose to in-license or acquire other product candidates as well as commercial products to treat patients suffering from neurodegenerative diseases and CNS or other disorders with significant unmet medical needs and limited treatment options. For example, in July 2024, we completed the acquisition of substantially all of the rights, title and interests in, to and under those assets and interests used by Eiger in the development, manufacture and commercialization of avexitide. Avexitide and any other potential product candidates have and will require additional, time-consuming development efforts prior to commercial sale, including preclinical studies, clinical trials and approval by the FDA and/or other applicable foreign regulatory authorities. All product candidates are prone to the risks of failure that are inherent in pharmaceutical product development, including the possibility that the product candidate will not be shown to be sufficiently safe and effective for approval by regulatory authorities. In addition, we cannot assure you that any such products that are approved will be manufactured or produced economically, successfully commercialized or widely accepted in the marketplace or be more effective than other commercially available alternatives. Research activities to identify product candidates require substantial technical, financial and human resources, whether or not any product candidates are ultimately identified. Our research activities or observation of third-party research activities may initially show promise in identifying potential product candidates, yet fail to yield product candidates for clinical development for many reasons, including the following: - the research methodology used may not be successful in identifying potential product candidates;- competitors may develop alternatives that render our potential product candidates obsolete;- product candidates that we develop may nevertheless be covered by third parties' patents or other exclusive rights;- a product candidate may, on further study, be shown to have harmful side effects or other characteristics that indicate it is unlikely to be effective or otherwise does not meet applicable regulatory criteria;- a product candidate may not be capable of being produced in commercial quantities at an acceptable cost, or at all; and - a product candidate may not be accepted as safe and effective by patients, the medical community or third-party payors. If we are unsuccessful in identifying and developing additional product candidates, our potential for growth and achieving our strategic objectives may be impaired.

Because we have limited financial and managerial resources, we are focused on specific indications and modifications for avexitide, AMX0035, AMX0114, and AMX0318. As a result, we may fail to generate additional clinical development opportunities for such candidates for a number of reasons, including, that such candidates may in certain indications, on further study, be shown to have harmful side effects, limited to no efficacy, or other characteristics that suggest it is unlikely to receive marketing approval and achieve market acceptance in such additional indications. For example, in August 2025, we announced the decision to discontinue the ORION program of AMX0035 in adults living with PSP, based on data from the Phase 2b trial, where AMX0035 did not show differences compared to placebo on primary or secondary outcomes at Week 24. We are conducting a clinical trial of avexitide in PBH and may conduct others in other indications as well. As a result, we may forgo or delay pursuit of opportunities with other indications that we believe could have had greater commercial potential or likelihood of success. In addition, we are continuing to evaluate plans to explore the use of other product candidates in ALS and additional neurodegenerative diseases. However, we may focus on or pursue one or more of our target indications over other potential indications and product candidates. Such development efforts may not be successful, which would cause us to delay the clinical development and approval of avexitide, AMX0035, AMX0114, AMX0318 and other product candidates. Furthermore, research activities to identify additional indications for avexitide, AMX0035, AMX0114, AMX0318 and other product candidates require substantial technical, financial, and human resources. We may not successfully develop these additional modifications for chemistry-related, stability-related, or other reasons. Our resource allocation decisions may cause us to fail to capitalize on viable commercial products or profitable market opportunities. Our spending on current and future research and development activities for specific indications or formulations of avexitide, AMX0035, AMX0114 or for AMX0318 or other product candidates may not yield any commercially viable products. Additionally, we may pursue in-licenses or acquisitions of development-stage assets or programs, which entails additional risk to us. For example, in July 2024, we completed the acquisition of substantially all of the rights, title and interests in, to and under those assets and interests used by Eiger in the development, manufacture and commercialization of avexitide, and in December 2024, we entered into a collaboration and license agreement with Gubra, which provides us an exclusive license to develop, manufacture, commercialize and otherwise exploit any development candidate and product(s) arising in the performance of activities under the agreement. Identifying, selecting and acquiring promising product candidates requires substantial technical, financial, and human resources expertise and, once acquired, requires us to devote substantial resources. Efforts to do so may not result in the actual acquisition or license of a particular product candidate, and, if acquired, may results in extensive diligence and preparation efforts, each of which may potentially result in a diversion of our management's time and the expenditure of our resources with no resulting benefit. For example, if we are unable to identify programs that ultimately result in approved products, we may spend material amounts of our capital and other resources evaluating, acquiring and developing products that ultimately do not provide a return on our investment.

We have focused our research and development efforts on addressing neurodegenerative diseases and have only in the past two years further expanded upon our existing development efforts in the endocrine and metabolic field with the acquisition of avexitide. This shift in focus resulted in additional costs arising from operating expenses and hiring personnel, challenges with building our expertise in the endocrine and metabolic field, or diversion of management's attention away from AMX0035. Historically, efforts by pharmaceutical companies in the field of neurodegenerative diseases have experienced limited successes in product development. The development of neurodegenerative therapies presents unique challenges, including an imperfect understanding of the relevant biology, the presence of the blood brain barrier that can restrict the flow of drugs to the brain, a frequent lack of translatability of preclinical study results in subsequent clinical trials and dose selection, and the product candidate having an effect that may be too small to be detected using the outcome measures selected in clinical trials or if the outcomes measured do not reach statistical significance. There are few approved therapeutic options available for patients with ALS and other neurodegenerative disorders. Our future success is highly dependent on the successful development and commercialization of avexitide, AMX0035 and any other current or future product candidates for treating neurodegenerative diseases or for treating endocrine conditions. Developing and commercializing avexitide, AMX0035 and any other current or future product candidates for treatment of neurodegenerative diseases or for treating PBH and congenital HI subjects us to a number of challenges, including ensuring that we have developed or acquired the requisite expertise in these areas, selected the optimal doses, execute appropriate clinical trials to test for efficacy and obtain regulatory approval from the FDA and other comparable foreign regulatory authorities.

To obtain regulatory approval to commercialize avexitide, AMX0035, AMX0114, AMX0318 and any other current or future product candidates, we must demonstrate through extensive preclinical studies and clinical trials that such product candidates are safe and effective in humans. Preclinical and clinical testing are expensive and can take many years to complete, and their outcome is inherently uncertain. The leadership changes at the FDA may compound this uncertainty. Failure can occur at any time during the clinical trial process and our future clinical trial results may not be successful, which could impact our ability to obtain regulatory approvals for avexitide, AMX0035, AMX0114, AMX0318 or any other current or future product candidates. We may experience delays in completing our clinical trials or preclinical studies and initiating or completing additional clinical trials. We may also experience numerous unforeseen events during our clinical trials that could delay or prevent our ability to receive marketing approval or commercialize avexitide, AMX0035, AMX0114, AMX0318 or any other current or future product candidates we develop, including: - regulators, or institutional review boards, or IRBs, or other reviewing bodies may not authorize us or our investigators to commence a clinical trial, or to conduct or continue a clinical trial at a prospective or specific trial site;- we may not reach agreement on acceptable terms with prospective contract research organizations, or CROs, and clinical trial sites, the terms of which can be subject to extensive negotiation and may vary significantly among different CROs and trial sites;- the number of subjects or patients required for clinical trials of avexitide, AMX0035, AMX0114 and AMX0318 in an indication or any future product candidate may be larger than we anticipate, enrollment in these clinical trials may be insufficient or slower than we anticipate, and the number of clinical trials being conducted at any given time may be high and result in fewer available patients for any given clinical trial, or patients may drop out of these clinical trials at a higher rate than we anticipate;- our third-party contractors, including those manufacturing avexitide, AMX0035, AMX0114, AMX0318 or any other current or future product candidates or conducting clinical trials on our behalf, may fail to comply with regulatory requirements or meet their contractual obligations to us in a timely manner, or at all;- we may have to amend clinical trial protocol submitted to regulatory authorities or conduct additional studies to reflect changes in regulatory requirements or guidance, which we may be required to resubmit to an IRB and regulatory authorities for re-examination;- unforeseen safety events may occur during the course of a clinical trial and these events may result in the temporary suspension or termination of a clinical trial, or require urgent safety measures or restrictions to protect human subjects during the conduct of a clinical trial;- regulators, IRBs or other reviewing bodies may fail to approve or subsequently find fault with the manufacturing processes or facilities of third-party manufacturers with which we enter into agreement for clinical and commercial supplies, or the supply or quality of avexitide, AMX0035, AMX0114, AMX0318 or any other current or future product candidate or other materials necessary to conduct clinical trials of avexitide, AMX0035, AMX0114, AMX0318 or any other current or future product candidates may be insufficient, inadequate or not available at an acceptable cost, or we may experience interruptions in supply; and - the potential for approval policies or regulations of the FDA or any other applicable foreign regulatory agencies to significantly change in a manner rendering our clinical data insufficient for approval. Regulators, IRBs of the institutions in which clinical trials are being conducted or data monitoring committees may suspend or terminate a clinical trial due to a number of factors, including failure to conduct the clinical trial in accordance with regulatory requirements or our clinical protocols, inspection of the clinical trial operations or trial site by the FDA or other regulatory authorities resulting in the imposition of a clinical hold, unforeseen safety issues or adverse side effects, failure to demonstrate a benefit from using a drug, changes in governmental regulations or administrative actions or lack of adequate funding to continue the clinical trial. For example, we submitted an IND application to the FDA for AMX0114. In connection with the IND application, the FDA restricted AMX0114 dosing to an amount that is lower than our proposed starting dose of 12.5 mg and requested additional information, which resulted in a clinical hold. Toxicology studies showed a greater than 10x safety margin at the starting dose of 12.5 mg based on the no observed adverse effect level determined by independent toxicology firms. In January 2025, we announced that the clinical hold had been lifted. However, there can be no assurance that the FDA or other regulatory authorities will not impose future clinical holds relating to any of our current or future product candidates. In July 2024, we completed the acquisition of substantially all of the rights, title and interests in, to and under those assets and interests used by Eiger BioPharmaceuticals, Inc., or Eiger, in the development, manufacture and commercialization of avexitide. Negative or inconclusive impressions of the results from earlier clinical trials of avexitide performed by Eiger or any other clinical trial or preclinical studies in animals that we or Eiger have conducted with respect to avexitide, or the results from our earlier clinical trials of AMX0035 for the treatment of ALS or AD, could mandate repeated or additional preclinical studies or clinical trials and could delay marketing approvals or result in changes to or delays in preclinical studies or clinical trials of AMX0035 in other indications. We do not know whether any clinical trials that we may conduct will demonstrate adequate efficacy and safety to result in regulatory approval to market avexitide, AMX0035 for our intended indications or any future product candidate. Our failure to successfully initiate and complete clinical trials of avexitide, AMX0035 for Wolfram syndrome or potential additional indications and to demonstrate the efficacy and safety of avexitide and AMX0035, including each component thereof, necessary to obtain regulatory approval to market avexitide and AMX0035, would significantly harm our business and ability to continue developing and marketing avexitide and AMX0035 for any indications. Our product candidate development costs will also increase if we experience delays in testing or obtaining and maintaining regulatory approvals and we may be required to obtain additional funds to complete clinical trials. We cannot assure you that our clinical trials will begin as planned or be completed on schedule, if at all, or that we will not need to restructure our trials after they have begun. Significant clinical trial delays or the need for additional data from our clinical trials also could shorten any periods during which we may have the exclusive right to commercialize avexitide, AMX0035 or any other current or future product candidates or allow our competitors to bring products to market before we do and impair our ability to successfully commercialize such product candidates, which may harm our business and results of operations. In addition, many of the factors that cause, or lead to, delays of clinical trials may ultimately lead to the denial of regulatory approval of avexitide, AMX0035 or any future product candidate.

Undesirable side effects caused by avexitide, AMX0035, AMX0114, AMX0318 or any future product candidate, could cause us or regulatory authorities to interrupt, delay or halt clinical trials and could result in a more restrictive label or the delay, denial or withdrawal of regulatory approval by the FDA or comparable foreign regulatory authorities. Results of our preclinical studies or clinical trials could reveal a high and unacceptable severity and prevalence of side effects or unexpected characteristics. In clinical trials to date of avexitide, avexitide was generally well-tolerated. The most common AEs were injection site bruising, headache, and nausea; these occurred more often with placebo than either avexitide dose. However, there can be no guarantee that we would observe a similar tolerability profile of avexitide in future clinical trials or for other indications. In clinical trials of AMX0035 to date, AMX0035 has been generally well-tolerated, with most common treatment-emergent AEs including diarrhea, abdominal pain, nausea, upper respiratory infection, constipation, headache, fatigue, proteinuria, and decreased appetite. In addition, it has been reported that patients experience a bad taste when taking AMX0035. In animal studies, administration of AMX0035 to rats throughout pregnancy and lactation resulted in increased offspring mortality at all doses tested, which were less than or similar to the clinical doses tested in our clinical trials. However, there can be no guarantee that we would observe a similar tolerability profile of AMX0035 in future clinical trials or for other indications. Many compounds that initially showed promise in clinical or earlier stage testing are later found to cause undesirable or unexpected side effects that prevented further development of the compound. If unacceptable or severe side effects arise in the development of avexitide, AMX0035, AMX0114, AMX0318 or any other current or future product candidates, we, the FDA or comparable foreign regulatory authorities, the IRBs, or independent ethics committees at the institutions in which our trials are conducted, or the independent safety monitoring committee could suspend or terminate our clinical trials or regulatory authorities could order us to cease clinical trials or deny approval of avexitide, AMX0035, AMX0114, AMX0318 or any other current or future product candidates for any or all targeted indications. Treatment-emergent side effects that are deemed to be drug-related could also affect subject recruitment or the ability of enrolled subjects to complete the trial or result in potential product liability claims. Undesirable side effects in one of our clinical trials for AMX0035 in one indication or avexitide could adversely affect enrollment in clinical trials, regulatory approval and commercialization of AMX0035 in other indications or avexitide. Additionally, there may be negative findings regarding components of avexitide, AMX0035, AMX0114, AMX0318 or future product candidates by other parties. Any negative findings by third parties may impact the future approvability or labeling of avexitide, AMX0035, AMX0114, AMX0318 or other product candidates we may develop. In addition, side effects may not be appropriately recognized or managed by the treating medical staff. Inadequate training in recognizing or managing the potential side effects of avexitide, AMX0035, AMX0114, AMX0318 or any future product candidates could result in patient injury or death. Any of these occurrences may harm our business, financial condition and prospects significantly. Bitter taste was frequently observed in our clinical trials of AMX0035. While bitter taste, by itself, does not present a safety risk for patients, it may lead to higher levels of patient non-compliance, which could have the effect of reducing the observed efficacy of AMX0035 in our clinical trials, or limit its commercial adoption. AMX0035 is a combination of TURSO and PB. PB has been approved by the FDA and other regulatory authorities for the treatment of patients with certain urea cycle disorders and TURSO has been approved in Italy for diseases of cirrhotic liver disorders such as primary biliary cirrhosis. It is possible that one or more of the active moieties in AMX0035 has also been approved by the FDA or other regulatory authorities. Even if AMX0035 receives marketing approval and is commercialized in a jurisdiction, we would continue to be subject to the risks that the applicable regulatory authorities could revoke approval of PB or TURSO or any active moiety in AMX0035, if applicable, or that efficacy, manufacturing or supply issues could arise with PB or TURSO or any active moiety in AMX0035, if applicable. This could result in our own products being removed from the market or being less commercially successful. Finally, clinical trials of avexitide, AMX0035 and AMX0114 are conducted in carefully defined sets of patients who have agreed to enter into clinical trials. Consequently, it is possible that our clinical trials, or those of any future collaborator, may indicate an apparent positive effect of avexitide, AMX0035, AMX0114, AMX0318 or any other current or future product candidate that is greater than the actual positive effect, if any, or alternatively fail to identify undesirable side effects.

Regulatory authorities in some jurisdictions, including the U.S. and the EU, may designate drugs 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 people in the U.S., or a patient population of greater than 200,000 people in the U.S., but for which there is no reasonable expectation that the cost of developing the drug will be recovered from sales in the U.S. In the EU, an orphan designation may be granted in respect of products that are intended for the diagnosis, prevention or treatment of a life-threatening or chronically debilitating condition affecting no more than five in 10,000 people in the EU when the application is made. Additionally, designation is granted for products intended for the diagnosis, prevention or treatment of a life-threatening or chronically debilitating condition when, without incentives, it is unlikely that sales of the product in the EU would be sufficient to justify the necessary investment in developing the product. In either case, the applicant for orphan designation must also demonstrate that no satisfactory method of diagnosis, prevention, or treatment for the condition has been authorized (or, if such a method exists, the new product would be a significant benefit to those affected compared to the product available). We received Orphan Drug Designation status for AMX0035 for the treatment of patients with Wolfram syndrome in the U.S. in November 2020. Eiger received Orphan Drug Designation status for avexitide for the treatment of hyperinsulinemic hypoglycemia (which includes PBH and congenital HI) in the U.S. in December 2016 and orphan designation for congenital HI in the EU from the European Commission in November 2019. Generally, if a drug with an Orphan Drug Designation subsequently receives the first marketing approval for the indication for which it has such designation, the drug may be entitled to a period of marketing exclusivity, which precludes the FDA or the other regulatory bodies from approving another marketing authorization application for the same drug in the same approved use or indication for that time period. Another drug may receive marketing approval prior to avexitide or AMX0035. The applicable period is seven years in the U.S. and ten years in the EU, which may be extended by six months and two years, respectively, in the case of product candidates that have complied with the respective regulatory agency's agreed upon pediatric investigation plan. The exclusivity period in the EU may be reduced to six years if, at the end of the fifth year, it is demonstrated that a product no longer meets the criteria for orphan designation or if the product is sufficiently profitable so that market exclusivity is no longer justified. In the EU, during the ten-year period of orphan marketing exclusivity, 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 similar medicinal products to the authorized orphan product. A "similar medicinal product" is defined as a medicinal product containing a similar active substance or substances as contained in an authorized orphan medicinal product, and which is intended for the same therapeutic indication. Legislation has been proposed by the European Commission and is progressing through the EU legislative process that, if adopted, could reduce the ten-year period of orphan marketing exclusivity for certain orphan medicinal products. Orphan drug exclusivity may be lost if the FDA or the EMA determines that the request for designation was materially defective or if the manufacturer is unable to assure sufficient quantity of the drug to meet the needs of patients with the rare disease or condition. In addition, even after a drug is granted orphan exclusivity and approved, the FDA and the EMA can subsequently approve another drug for the same approved use or indication before the expiration of the seven-year (or ten-year in the EU) exclusivity period if the FDA or the EMA concludes that the later drug is clinically superior in that it is shown to be safer, more effective or makes a major contribution to patient care. In addition, if an orphan designated product receives marketing approval for an indication broader than or different from what is designated, such product may not be entitled to orphan exclusivity. Even though the FDA has granted Orphan Drug Designation to AMX0035 for the treatment of Wolfram syndrome, if we receive approval for AMX0035 for a modified or different indication, our current Orphan Drug Designation may not provide us with exclusivity. Orphan Drug Designation does not convey any advantage in, or shorten the duration of, the regulatory review or approval process. Also, regulatory approval for any product candidate may be withdrawn, and other product candidates may obtain approval before us and receive orphan drug exclusivity, which could block us from entering the market. Even if we obtain orphan drug exclusivity for avexitide or AMX0035, that exclusivity may not effectively protect us from competition because different drugs can be approved for the same approved use or indication before the expiration of the orphan drug exclusivity period. For example, even though AMX0035 is entitled to orphan drug exclusivity, that exclusivity may not prevent the approval of TURSO by the FDA or other regulatory authorities as a monotherapy treatment for Wolfram syndrome if those regulatory agencies determine that TURSO is a different drug product from AMX0035. In addition, the regulatory authorities may find that this monotherapy treatment is clinically superior to our fixed dose product and approve it even if we are granted orphan drug exclusivity. U.S. lawmakers have also recently raised the possibility that regulatory or legislative changes might need to be made to the Orphan Drug Act to foster competition. This includes the introduction of legislation that, if adopted into law, would require us to demonstrate to the FDA that avexitide or AMX0035 would be economically unviable when facing competition to maintain our exclusivity.

Periodically, we make estimates regarding the incidence and prevalence of target patient populations based on various third-party sources and internally generated analysis. Our estimates may be inaccurate or based on imprecise data. As described above, 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 people in the U.S., or a patient population of greater than 200,000 people in the U.S., but for which there is no reasonable expectation that the cost of developing the drug will be recovered from sales in the U.S. If our incidence or prevalence estimates for future indications for which we may seek Orphan Drug Designation are incorrect, we may be unable to receive Orphan Drug Designation. Even if the FDA grants Orphan Drug Designation for avexitide or AMX0035 for other indications, exclusive marketing rights in the U.S. may be limited if we seek FDA marketing approval for an indication broader than the orphan designated indication. Additionally, any product candidate that initially receives orphan drug status designation, may lose such designation 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. In addition, others may obtain orphan drug status for products addressing the same diseases or conditions as products we are developing, thus limiting our ability to compete in the markets addressing such diseases or conditions for a significant period of time. As a result, our business and prospects could suffer.

If the FDA determines that a product candidate offers a treatment for a serious condition and, if approved, the product would provide a significant improvement in safety or effectiveness, the FDA may designate the product candidate for priority review. A Priority Review Designation means that the goal for the FDA to review an application is six months, rather than the standard review period of ten months. For example, we received priority review for AMX0035 for the treatment of ALS, and we may in the future request Priority Review Designation for any future product candidates, however, we cannot assume that any application for future indications of avexitide, AMX0035 or any other product candidate we may develop will meet the criteria for that designation. The FDA has broad discretion with respect to whether or not to grant priority review status to a product candidate, so even if we believe a particular product candidate is eligible for such designation or status, the FDA may decide not to grant it. Moreover, a Priority Review Designation does not necessarily mean a faster development or regulatory review or approval process or necessarily confer any advantage with respect to approval compared to standard FDA review and approval. For example, the FDA originally set the PDUFA date for AMX0035 for the treatment of ALS, for June 29, 2022, and then extended the review timeline for our NDA to September 2022. Receiving priority review from the FDA does not guarantee approval within the six-month review cycle or at all.

In June 2025, we announced receipt of Fast Track Designation for AMX0114 for the treatment of ALS. We may in the future seek Fast Track Designation for product candidates we develop. If a product is intended for the treatment of a serious or life-threatening condition and preclinical or clinical data demonstrate the potential to address an unmet medical need for this condition, the product sponsor may apply for Fast Track Designation. The FDA has broad discretion whether or not to grant this designation, so even if we believe a particular product candidate is eligible for this designation, we cannot assure you that the FDA would decide to grant it. Even if we do receive Fast Track Designation, we may not experience a faster development process, review or approval compared to conventional FDA procedures. The FDA may rescind the Fast Track Designation if it believes that the designation is no longer supported by data from our clinical development activities.