Rhythm Pharmaceuticals (RYTM) Risk Analysis

From time to time, we may publicly disclose preliminary or topline data from our preclinical studies and clinical trials, which is based on a preliminary analysis of then-available data, and the results and related findings and conclusions are subject to change following a more comprehensive review of the data related to the particular study or trial. We make assumptions, estimations, calculations and conclusions as part of our analyses of data, and we may not have received or had the opportunity to fully and carefully evaluate all data. As a result, the topline or preliminary results that we report may differ from future results of the same studies, or different conclusions or considerations may qualify such results, once additional data have been received and fully evaluated. Topline data 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 or reported. As a result, topline data should be viewed with caution until the final data are available. From time to time, we may also disclose interim data from our preclinical studies and 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. Adverse differences between preliminary or interim data and final data could significantly harm our business prospects. Further, disclosure of interim data by us or by our competitors could result in volatility in the price of our common stock. From time to time, we may also disclose real-world data from early access programs in particular patient cohorts, which are not controlled trials and may not be predictive of future results. Further, others, including regulatory agencies, may not accept or agree with our assumptions, estimates, calculations, conclusions or analyses or may interpret or weigh the importance of data differently, which could impact the value of a particular program, the approvability or commercialization of the particular product candidate or product and our Company in general. In addition, the information we choose to publicly disclose regarding a particular study or clinical trial is based on what is typically extensive information, and others may not agree with what we determine is material or otherwise appropriate information to include in our disclosure. If the interim, topline, or preliminary data that we report differ from actual results, or if others, including regulatory authorities, disagree with the conclusions reached, our ability to obtain approval for, and commercialize, our product candidates may be harmed, which could harm our business, operating results, prospects or financial condition.

We may not be able to initiate or continue our planned clinical trials on a timely basis or at all for our product candidates if we are unable to recruit and enroll a sufficient number of eligible patients to participate in these trials through completion of such trials as required by the FDA or other comparable foreign regulatory authorities. Patient enrollment is a significant factor in the timing of clinical trials. Our ability to enroll eligible patients may be limited or may result in slower enrollment than we anticipate. Our clinical trials will compete with other clinical trials that are in the same therapeutic areas as our product candidates, including general obesity, and this competition reduces the number and types of patients available to us, as some patients who might have opted to enroll in our trials may instead opt to enroll in a trial being conducted by one of our competitors. Because the number of qualified clinical investigators and clinical trial sites is limited, we expect to conduct some of our clinical trials at the same clinical trial sites that some of our competitors use, which will reduce the number of patients who are available for our clinical trials at such clinical trial sites. In addition, there are limited patient pools from which to draw for clinical studies. In addition to the rarity of genetic diseases of obesity, the eligibility criteria of our clinical studies will further limit the pool of available study participants as we will require that patients have specific characteristics that we can measure or to assure their disease is either severe enough or not too advanced to include them in a study. Patient enrollment for our current or any future clinical trials may be affected by other factors, including: - size and nature of the patient population;- severity of the disease under investigation;- availability and efficacy of approved drugs for the disease under investigation;- patient eligibility criteria for the trial in question as defined in the protocol;- perceived risks and benefits of the product candidate under study;- clinicians' and patients' perceptions as to the potential advantages of the product candidate being studied in relation to other available therapies, including any new products that may be approved or future product candidates being investigated for the indications we are investigating;- clinicians' willingness to screen their patients for genetic markers to indicate which patients may be eligible for enrollment in our clinical trials;- delays in or temporary suspension of the enrollment of patients in our planned clinical trial due to public health emergencies;- ability to obtain and maintain patient consents;- patient referral practices of physicians;- the ability to monitor patients adequately during and after treatment;- proximity and availability of clinical trial sites for prospective patients; and - the risk that patients enrolled in clinical trials will drop out of the trials before completion, including as a result of health conditions or being forced to quarantine, or, because they may be late-stage cancer patients or for other reasons, will not survive the full terms of the clinical trials. In addition, the pediatric population is an important patient population for setmelanotide, RM-718, and bivamelagon, and our addressable patient population estimates include pediatric populations. However, it may be more challenging to conduct studies in younger participants, and to locate and enroll pediatric patients. These factors may make it difficult for us to enroll enough patients to complete our clinical trials in a timely and cost-effective manner. Our inability to enroll a sufficient number of patients for our clinical trials would result in significant delays or may require us to abandon one or more clinical trials altogether. Enrollment delays in our clinical trials may also result in increased development costs for setmelanotide and any future product candidates and jeopardize our ability to obtain additional marketing approvals for the sale of setmelanotide. Furthermore, even if we are able to enroll a sufficient number of patients for our clinical trials, we may have difficulty maintaining participation in our clinical trials through the treatment and any follow-up periods.

Successful completion of our ongoing and planned clinical trials is a prerequisite to submitting an NDA or NDA supplement to the FDA, a marketing authorization application ("MAA") to the EMA, and other applications for marketing authorization to equivalent competent authorities in foreign jurisdictions, and consequently, successful completion of such trials, at a minimum, will be required for regulatory approvals and the commercial marketing of setmelanotide for additional indications as well as RM-718 and bivamelagon. We do not know whether our planned clinical trials will begin or whether any of our clinical trials will be completed on schedule, if at all, as the commencement and successful completion of clinical trials can be delayed or prevented for a number of reasons, including but not limited to: - inability to generate sufficient preclinical or other in vivo or in vitro data to support the initiation of clinical studies;- delays in the completion of preclinical laboratory tests, animal studies and formulation studies in accordance with FDA's good laboratory practice requirements and other applicable regulations;- the FDA or other equivalent competent authorities in foreign jurisdictions may deny permission to proceed with our ongoing or planned trials or any other clinical trials we may initiate, or may place a clinical trial on hold or such trial may be suspended;- delays in filing or receiving authorization to proceed under an additional investigational new drug application, or IND, or similar foreign application if required;- delays in reaching a consensus with the FDA and other regulatory agencies on study design and obtaining regulatory authorization to commence clinical trials;- delays in reaching or failing to reach agreement on acceptable terms with prospective 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;- difficulties in obtaining or maintaining Institutional Review Board, or IRB, and/or ethics committee approval or opinion to conduct a clinical trial at a prospective site or sites;- since many already diagnosed patients are at academic sites, delays in conducting clinical trials at academic sites due to the particular challenges and delays typically associated with those sites, as well as the lack of alternatives to these sites which have already diagnosed patients;- inadequate quantity or quality of setmelanotide, RM-718, bivamelagon or other materials necessary to conduct clinical trials, including delays in the manufacturing of sufficient supply of finished drug product;- challenges in identifying, recruiting and training suitable clinical investigators;- challenges in recruiting and enrolling suitable patients to participate in clinical trials;- severe or unexpected drug related side effects experienced by patients in a clinical trial, including side effects previously identified in our completed clinical trials;- difficulty collaborating with patient groups and investigators;- failure by our CROs, other third parties or us to perform in accordance with the FDA's or any other regulatory authority's GCPs or applicable regulatory guidelines in other countries;- occurrence of adverse events associated with setmelanotide, RM-718 or bivamelagon that are viewed to outweigh their potential benefits, or occurrence of adverse events in trial of the same or similar class of agents conducted by other companies;- changes to the clinical trial protocols;- clinical sites deviating from trial protocol or dropping out of a trial;- changes in regulatory requirements and guidance that require amending or submitting new clinical protocols;- changes in the standard of care on which a clinical development plan was based, which may require new or additional trials;- selection of clinical endpoints that require prolonged periods of observation or analyses of resulting data;- the cost of clinical trials of our product candidates being greater than we anticipate;- clinical trials or related non-clinical trials of our product candidates producing negative or inconclusive results, which may result in our deciding, or regulators requiring us, to conduct additional clinical trials or delay or abandon development of such product candidates; and - development of antibodies to the drug or adjuvants may result in loss of efficacy or safety events. In addition, a clinical trial may be suspended or terminated by us, the FDA or other equivalent competent authorities in foreign jurisdictions, the IRB at the sites where the IRBs are overseeing a clinical trial, a data and safety monitoring board, or DSMB, or Safety Monitoring Committee, or SMC, overseeing the clinical trial at issue or other equivalent competent authorities due to a number of factors, including, among others: - failure to conduct the clinical trial in accordance with regulatory requirements or our clinical trial protocols;- inspection of the clinical trial operations or trial sites by the FDA or other equivalent competent authorities that reveals deficiencies or violations that require us to undertake corrective action, including the imposition of a clinical hold;- inconclusive results, unforeseen safety issues, adverse side effects or lack of effectiveness;- changes in government regulations or administrative actions;- problems with clinical trial supply materials; and - lack of adequate funding to continue the clinical trial. Delays in the completion of any preclinical or non-clinical studies or clinical trials of setmelanotide, RM-718 or bivamelagon will increase our costs, slow down our product candidate development and the regulatory approval processes and delay or potentially jeopardize our ability to commence product sales, generate product revenue and achieve profitability. In addition, many of the factors that cause, or lead to, a delay in the commencement or completion of clinical trials may also ultimately lead to the denial of a regulatory approval for setmelanotide, RM-718 or bivamelagon. Any delays to our preclinical studies or clinical trials that occur as a result could shorten any period during which we may have the exclusive right to commercialize setmelanotide, RM-718 or bivamelagon, in each case if approved, and our competitors may be able to bring products to market before we do, and the commercial viability of our product candidates could be significantly reduced. Any of these occurrences may harm our business, financial condition and prospects significantly. In addition, the FDA's and other regulatory authorities' policies with respect to clinical trials may change and additional government regulations may be enacted. For instance, the EU Clinical Trials Regulation (CTR) which was adopted in April 2014 and repeals the EU Clinical Trials Directive, became applicable on January 31, 2022. While the EU Clinical Trials Directive required a separate clinical trial application (CTA) to be submitted in each member state in which the clinical takes place, to both the competent national health authority and an independent ethics committee, the CTR introduces a centralized process and only requires the submission of a single application for multi-center trials. The CTR allows sponsors to make a single submission to both the competent authority and an ethics committee in each member state, leading to a single decision per member state. The assessment procedure of the CTA has been harmonized as well, including a joint assessment by all member states concerned, and a separate assessment by each member state with respect to specific requirements related to its own territory, including ethics rules. Each member state's decision is communicated to the sponsor via the centralized EU portal. Once the CTA is approved, clinical study development may proceed. The CTR transition period ended on January 31, 2025 and all clinical trials (and related applications) are now fully subject to the provisions of the CTR. Compliance with the CTR requirements by us and our third-party service providers, such as CROs, may impact our development plans. Furthermore, on April 28, 2025, the UK adopted an amendment to the UK clinical trials regulations intended to support a more streamlined and flexible regulation of clinical trials, removing unnecessary administrative burdens on trial sponsors, whilst protecting the interests of trial participants. It also intends to bring the UK regulatory framework for clinical trials, which is still based on the EU Clinical Trials Directive, into closer alignment with the (EU) CTR. The amendment became applicable on April 28, 2026 following a one-year transition period. If we are slow or unable to adapt to changes in existing requirements or the adoption of new requirements or policies governing clinical trials, our development plans may be impacted.

Research and development in the pharmaceutical industry is an expensive, high-risk, lengthy, complicated, resource intensive process. In order to develop a product successfully, we must, among other things: - conduct scientific discovery in areas that are uncertain, unproven and complex;- identify potential product candidates;- submit for and receive regulatory approvals or allowances to perform clinical trials;- design and conduct appropriate preclinical studies and clinical trials according to good laboratory practices and good clinical practices and disease-specific expectations of the FDA and other regulatory bodies;- Select and recruit suitable clinical investigators and subjects for our clinical trials;- Obtain and correctly interpret data establishing adequate safety of our product candidates and demonstrating that our product candidates are effective for their proposed indications;- Submit for and receive regulatory approvals; and - Manufacture the product candidates according to current Good Manufacturing Practices, or cGMPs, and other applicable standards and regulations. There is a high rate of failure inherent in this process, and potential products that appear promising at early stages of the research and development process may fail for a number of reasons. Importantly, positive results from preclinical studies of a product candidate may not be predictive of similar results in human clinical trials, promising results from earlier clinical trials of a product candidate may not be replicated in later clinical trials, and observations from ongoing trials, including observations based on interim, preliminary, or blinded data, may not be representative of results after the trials are completed and all data are collected and analyzed. Many companies in the pharmaceutical and biotechnology industries have suffered significant setbacks in late-stage clinical trials even after achieving positive results in earlier stages of development and have abandoned development efforts or sought partnerships in order to continue development. In addition, there are many other difficulties and uncertainties inherent in pharmaceutical research and development that could significantly delay or otherwise materially impair our ability to develop future product candidates, including the following: - Conditions imposed by regulators, ethics committees or institutional review boards for preclinical testing and clinical trials relating to the scope or design of our clinical trials, including selection of endpoints and number of required patients or clinical sites;- Challenges in designing clinical trials that may support any potential claims of superiority over current standard of care or future competitive therapies;- Restrictions placed upon, or other difficulties with respect to, clinical trials and clinical trial sites, including with respect to potential clinical holds or suspension or termination of clinical trials due to, among other things, potential safety or ethical concerns or noncompliance with regulatory requirements;- Delayed or reduced enrollment in clinical trials, high discontinuation rates or overly concentrated patient enrollment in specific geographic regions;- Failure by third-party contractors, contract research organizations, or CROs, clinical investigators, clinical laboratories, or suppliers to comply with regulatory requirements or meet their contractual obligations in a timely manner;- Greater than anticipated cost of our clinical trials; and - Insufficient product supply or inadequate product quality. - Evolving competitive landscape for our products and product candidates, which could cause us to modify our development programs, notwithstanding positive data or trial results in existing trials, in order to seek alternate indications or routes of administration or to substitute or otherwise modify our product candidates in light of the evolving competitive landscape and changing commercial prospects for our product and product candidates. In addition, we cannot state with certainty when or whether our CHI program will ever identify a product candidate to translate from research to the development stage or whether our other product candidates now under development will be approved or launched; whether, if initially granted, such approval will be maintained; whether we will be able to develop, license, or otherwise acquire additional products or product candidates; or whether our products, once launched, will be commercially successful. Failure to successfully develop setmelanotide for additional indications or to develop product candidates for any of the foregoing reasons may materially adversely affect our business, financial condition, results of operations and prospects and the value of our common stock.

First generation MC4R agonists were predominantly small molecules that failed in clinical trials due to significant safety issues, particularly increases in blood pressure, and had limited efficacy. Undesirable side effects caused by setmelanotide, RM-718 or bivamelagon could cause us or regulatory authorities to interrupt, delay or halt clinical trials and could result in a more restrictive labeling or the delay or denial of additional regulatory approvals by the FDA or other equivalent competent authorities in foreign jurisdictions. Treatment-related side effects could also affect patient recruitment or the ability of enrolled patients to complete the trial or result in potential product liability claims. Any of these occurrences may prevent us from achieving or maintaining market acceptance of the affected product candidate and may adversely affect our business, financial condition and prospects significantly. Setmelanotide, RM-718 and bivamelagon are MC4R agonists. Potential side effects of MC4R agonism, which have been noted either with setmelanotide or with other MC4R agonists in clinical trials and preclinical studies, may include: - adverse effects on cardiovascular parameters, such as increases in heart rate and blood pressure;- erections in males and similar effects in women, such as sexual arousal, clitoral swelling and hypersensitivity;- nausea and vomiting;- reduced appetite;- headache;- effects on mood, depression, anxiety and other psychiatric manifestations; and - other effects, for which an investigator reported as unrelated to setmelanotide or for which no increased incidence or pattern or causal relationship is currently evident. In addition, injection site reactions have been seen in subcutaneous, or SC, injections with setmelanotide. Also, setmelanotide has likely off target effects on the closely related MC1 receptor, which mediates skin pigmentation in response to sun exposure. Other MC1 receptor mediated effects include darkening of skin blemishes, such as freckles and moles, and hair color change. These MC1 receptor mediated skin effects are not tolerated by all patients, as a small number of patients have withdrawn from treatment due to skin darkening. These effects have generally been reversible in clinical trials after discontinuation of setmelanotide, but it is still unknown if they will be reversible with long term exposure. The MC1 receptor mediated effects may also carry risks. The long term impact of MC1 receptor activation has not been tested in clinical trials, and could potentially include increases in skin cancer, excess biopsy procedures and cosmetic blemishes. These skin changes may also result in unblinding, which could make interpretation of clinical trial results more complex and possibly subject to bias. We have also initiated trials of setmelanotide in potential new indications that include patients who might have more serious underlying conditions. It is possible that the underlying conditions in these patients, such as congestive heart failure and potentially other conditions, may confound the understanding of the safety profile of setmelanotide. If these or other significant adverse events or other side effects are observed in any of our ongoing or planned clinical trials, we may have difficulty recruiting patients to the clinical trials, patients may drop out of our trials, or we may be required to abandon the trials or our development efforts of that product candidate altogether. We, the FDA, other comparable regulatory authorities or an IRB may also suspend clinical trials of a product candidate at any time for various reasons, including a belief that subjects in such trials are being exposed to unacceptable health risks or adverse side effects. Some potential therapeutics developed in the biotechnology industry that initially showed therapeutic promise in early-stage trials have later been found to cause side effects that prevented their further development. Even if the side effects do not preclude setmelanotide, RM-718 or bivamelagon from obtaining or maintaining marketing approval or obtaining additional approvals, undesirable side effects may inhibit market acceptance due to its tolerability versus other therapies. Any of these developments could materially adversely affect our business, financial condition and prospects. Further, if we or others identify undesirable side effects associated with or caused by the products, or any other similar product, before or after regulatory approvals, a number of potentially significant negative consequences could result, including: - regulatory authorities may request that we withdraw the product from the market or may limit or vary their approval of the product through labeling or other means;- regulatory authorities may require the addition of labeling statements, such as a "boxed" warning or a contraindication;- the FDA, the EU competent authorities and other equivalent competent authorities in foreign jurisdictions may require the addition of a Risk Evaluation and Mitigation Strategy, or REMS, or other specific obligations as a condition for marketing authorization due to the need to limit treatment to rare patient populations, or to address safety concerns;- we may be required to change the way the product is distributed or administered or change the labeling of the product;- we may be required to conduct additional studies and clinical trials or comply with other post-market requirements to assess possible serious risks;- we may be required to conduct long term safety follow-up evaluations, including setting up disease and drug based registries;- we may decide to remove the product from the marketplace;- our other MC4 agonist products or product candidates may be perceived by regulators or other third parties as unsafe, which could adversely affect our development efforts and product portfolio;- we could be sued and held liable for injury caused to individuals exposed to or taking the product; and - our reputation may suffer. Any of these events could prevent us from achieving or maintaining market acceptance of setmelanotide, RM-718 or bivamelagon, and could substantially increase the costs of commercializing setmelanotide, RM-718 or bivamelagon and significantly impact our ability to successfully commercialize setmelanotide, RM-718 or bivamelagon and generate revenues.

The FDA is authorized under the FDCA to give certain product candidates "Breakthrough Therapy designation." A Breakthrough Therapy product candidate is defined as a product candidate that is intended, alone or in combination with one or more other drugs or biologics, to treat a serious or life-threatening disease or condition, where preliminary clinical evidence indicates that such product candidate may demonstrate substantial improvement on one or more clinically significant endpoints over existing therapies. The FDA will seek to ensure the sponsor of Breakthrough Therapy product candidate receives intensive guidance on an efficient drug development program, intensive involvement of senior managers and experienced staff on a proactive, collaborative and cross disciplinary review. In addition, the FDA may consider reviewing portions of an NDA before the sponsor submits the complete application, a process also known as rolling review. Product candidates designated as breakthrough therapies by the FDA may be eligible for other expedited programs, such as priority review, provided the relevant criteria are met. Designation as Breakthrough Therapy is within the discretion of the FDA. Accordingly, even if we believe our product candidates meet the criteria for designation as Breakthrough Therapy, the FDA may disagree. In any event, the receipt of Breakthrough Therapy designation for a product candidate, or acceptance for one or more of the FDA's other expedited programs, may not result in a faster development process, review or approval compared to products considered for approval under conventional FDA procedures and does not guarantee ultimate approval by the FDA. Regulatory standards to demonstrate safety and efficacy must still be met. Additionally, the FDA may later decide that the product candidate no longer meets the conditions for designation and may withdraw designation at any time or decide that the time period for FDA review or approval will not be shortened. The PRIME (PRIority MEdicines) scheme was launched by the EMA in 2016. In the EU, innovative products that target an unmet medical need and are expected to be of major public health interest may be eligible for a number of expedited development and review programs, such as the PRIME scheme, which provides incentives similar to the Breakthrough Therapy designation in the United States. PRIME is a voluntary scheme aimed at enhancing the EMA's support for the development of medicines that target unmet medical needs. It is based on increased interaction and early dialogue with companies developing promising medicines, to optimize their product development plans and speed up their evaluation to help them reach patients earlier. The benefits of a PRIME designation include the appointment of a rapporteur before submission of an MAA, early dialogue and scientific advice at key development milestones, and the potential to qualify products for accelerated review earlier in the application process. In late June 2018, setmelanotide was granted eligibility to PRIME by the Committee for Medicinal Products for Human Use, or CHMP for the treatment of obesity and the control of hunger associated with deficiency disorders of the MC4R receptor pathway. Acknowledging that setmelanotide targets an unmet medical need, the EMA offers enhanced support in the development of the medicinal product through enhanced interaction and early dialogue to optimize our development plans and speed up regulatory evaluation in the EU. As part of this designation, the EMA has provided guidance to us concerning the development of setmelanotide. However, the EMA may later decide that such product candidates no longer meet the conditions for qualification or decide that the time period for review or approval will not be shortened. Neither does the PRIME designation guarantee that the EC will grant additional marketing authorizations for setmelanotide. Product developers that benefit from PRIME designation may be eligible for accelerated assessment (in 150 days instead of 210 days), which may be granted for medicinal products of major interest from a public health perspective or that target an unmet medical need, but this is not guaranteed.