Climb Bio (CLYM) Risk Analysis

We conduct and may conduct future clinical trials with trial sites that are located outside the U.S. The acceptance by the FDA or other regulatory authorities of trial data from clinical trials conducted outside their jurisdiction may be subject to certain conditions or may not be accepted at all. Trials outside the U.S. also present operational risks, including complying with local regulations, foreign exchange rate risk, potentially more limited IP protection, and geopolitical risks that can add cost and delay to conducting clinical trials. For example, in cases where data from foreign clinical trials are intended to serve as the sole basis for marketing approval in the U.S., the FDA will generally not approve the application on the basis of foreign data alone unless (i) the data are applicable to the U.S. population and U.S. medical practice; (ii) the trials were performed by clinical investigators of recognized competence and pursuant to GCP regulations; and (iii) the data may be considered valid without the need for an on-site inspection by the FDA, or if the FDA considers such inspection to be necessary, the FDA is able to validate the data through an on-site inspection or other appropriate means. In addition, even where the foreign trial data are not intended to serve as the sole basis for approval, the FDA will not accept the data as support for an application for marketing approval unless the trial is well-designed and well-conducted in accordance with GCP requirements and the FDA is able to validate the data from the trial through an onsite inspection if deemed necessary. Many foreign regulatory authorities have similar approval requirements. In addition, such foreign trials would be subject to the applicable local laws of the foreign jurisdictions where the trials are conducted. There can be no assurance that the FDA or any comparable foreign regulatory authority will accept data from trials conducted outside of the U.S. or the applicable jurisdiction. If the FDA or any comparable foreign regulatory authority does not accept such data, it would result in the need for additional trials, which could be costly and time-consuming, and which may result in our product candidates not receiving approval for commercialization in the applicable jurisdiction. Conducting clinical trials outside the U.S. will also expose us to additional risks, including risks associated with: - additional foreign regulatory requirements;- foreign exchange fluctuations;- compliance with foreign manufacturing, customs, shipment and storage requirements;- cultural differences in medical practice and clinical research;- diminished protection of intellectual property in some countries; and - interruptions or delays in our trials resulting from geopolitical events, such as war or terrorism.

Drug development is a highly uncertain undertaking and involves a substantial degree of risk. For example, previously we paused or discontinued the development of all of our legacy product candidates for the treatment of neuronal excitability disorders, including ETX-155 and ETX-123, which were still in drug discovery stages, and we may not ever obtain regulatory approval for our product candidates. In addition, as a company, we have no prior experience developing biological product candidates. As such, we may encounter delays or difficulties in our efforts to develop and commercialize budoprutug and CLYM116. To date, we have not initiated or completed a pivotal clinical trial, obtained marketing approval for any product candidate, manufactured a commercial scale product or arranged for a third party to do so on our behalf, or conducted the sales and marketing activities necessary for successful product commercialization. Our short operating history as a company makes any assessment of our future success and viability subject to significant uncertainty. We will encounter risks and difficulties frequently experienced by early-stage biotechnology companies in rapidly evolving fields, and we have not yet demonstrated an ability to successfully overcome such risks and difficulties. If we do not address these risks and difficulties successfully, our business may be harmed.

We have received and may in the future seek certain designations for our product candidates that could expedite review and approval by the FDA. A Breakthrough Therapy product is defined as a product that is intended, alone or in combination with one or more other products, to treat a serious condition, and preliminary clinical evidence indicates that the product may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development. For products that have been designated as Breakthrough Therapies, interaction and communication between the FDA and the sponsor of the trial can help to identify the most efficient path for clinical development while minimizing the number of patients placed in ineffective control regimens. The FDA may also designate a product for Fast Track review if it is intended, whether alone or in combination with one or more other products, for the treatment of a serious or life-threatening disease or condition, and it demonstrates the potential to address unmet medical needs for such a disease or condition. For Fast Track review products, sponsors may have greater interactions with the FDA and the FDA may initiate review of sections of a Fast Track product's application before the application is complete. This rolling review may be available if the FDA determines, after preliminary evaluation of clinical data submitted by the sponsor, that a Fast Track review product may be effective. We have received Fast Track designation for budoprutug for the treatment of pMN and may seek Fast Track designation for budoprutug in other indications or for other of our product candidates, but such designation may not lead to a faster development or regulatory review and approval process or increase the likelihood that such product candidate will receive regulatory approval. We may also seek a Priority Review designation for our product candidates. If the FDA determines that a product candidate offers major advances in treatment or provides a treatment where no adequate therapy exists, the FDA may designate the product candidate for priority review. A Priority Review designation means that the goal is for the FDA to review an application for marketing approval in six months, rather than the standard review period of 10 months. On June 17, 2025, the FDA announced the creation of a new voucher program to expedite the development and approval of new drug products. Vouchers issued under the new program, which is known as the Commissioner's National Priority Voucher (CNPV) Program, may be redeemed by sponsors to shorten the review time of an NDA or BLA from approximately 10 to 12 months to potentially as short as one to two months. The FDA has indicated that the CNPV Program will convene experts from the FDA's offices for a team-based review rather than using the standard review system of a drug application being sent to numerous FDA offices. Clinical information will be reviewed by a multidisciplinary team of physicians and scientists who will pre-review the submitted information and convene for a one-day meeting. As of July 1, 2026, the FDA has issued 18 vouchers and approved seven products under this program. However, there have been significant changes in FDA's senior leadership since the launch of the CNPV Program, and industry stakeholders have raised concerns regarding the CNPV Program. Consequently, we do not know whether or under what circumstances FDA may continue to award vouchers or grant approvals under the CNPV Program. These designations are within the discretion of the FDA. Accordingly, even if we believe that our product candidates meet the criteria for these designations, the FDA may disagree and instead determine not to make such designation. Further, even if we receive a designation, the receipt of such designation for a product candidate may not result in a faster development or regulatory review or approval process compared to product candidates considered for approval under conventional FDA procedures and does not assure ultimate approval by the FDA. In addition, even if our product candidates qualify for these designations, the FDA may later decide that such product candidate no longer meets the conditions for qualification or decide that the time period for FDA review or approval will not be shortened. In the EU, we may seek PRIME designation for our product candidates. The PRIME program focuses on product candidates that target conditions for which there exists no satisfactory method of treatment in the EU, or even if such a method exists, the product candidate may offer a major therapeutic advantage over existing treatments. To be accepted for PRIME designation, a product candidate must meet the eligibility criteria in respect of its major public health interest and therapeutic innovation based on information that is capable of substantiating the claims. The benefits of a PRIME designation include the appointment of a rapporteur of the CHMP to provide continued support and help to build knowledge ahead of a marketing authorization application, early dialogue and scientific advice at key development milestones, and the potential to qualify products for accelerated review, meaning reduction in the review time for an opinion on approvability to be issued earlier in the application process. PRIME designation enables an applicant to request parallel EMA scientific advice and health technology assessment advice to facilitate timely market access. Even if we receive PRIME designation for our product candidates, the designation may not result in a materially faster development process, review or approval compared to conventional EMA procedures. Further, obtaining PRIME designation does not assure or increase the likelihood of EMA's grant of a marketing authorization.

From time to time, we may announce, present or publish preliminary, initial, or interim data or other information from our clinical trials, such as the initial Phase 1b data we announced from the Phase 1b/2a clinical trial of budoprutug in patients with ITP. Any such data and other results from our clinical trials may materially change as more patient data and information become available. Such data and information may also undergo significant change following subsequent auditing, validation and verification procedures that are commonly conducted in clinical trials. Thus, any preliminary, initial, or interim data or other information may not be predictive of final results from the clinical trial and should be viewed with caution until the final data are available. We may also arrive at different conclusions, or other determinations that may qualify such results, once we have received and fully evaluated the additional data. Differences between preliminary, initial or interim results and final results could lead to significantly different interpretations or conclusions of the trial outcomes. Further, others, including regulatory authorities and collaboration or regional partners, 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 our product candidates, the approvability or commercialization of our product candidates, and our business, in general. In addition, the information we choose to publicly disclose regarding a particular clinical trial is based on what is typically extensive information, and investors may not agree with what we determine is material or otherwise appropriate information to publicly disclose. If the preliminary, initial or interim 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 significantly harm our reputation, business, results of operations, financial condition and prospects.

To obtain the requisite regulatory approvals to commercialize our product candidates, we must demonstrate through extensive nonclinical studies and clinical trials that such product candidates are potent, safe and pure in humans to the satisfaction of the FDA. Clinical testing is expensive and can take many years to complete, and its outcome is inherently uncertain. A product candidate can fail at any stage of testing, even after observing promising signs of activity in earlier nonclinical studies or clinical trials. The results of nonclinical studies and early clinical trials of our product candidates may not be predictive of the results of later-stage clinical trials. Initial success in clinical trials may not be indicative of results obtained when such trials are completed. There is typically an extremely high rate of attrition from the failure of product candidates proceeding through clinical trials. Product candidates in later stages of clinical trials may fail to show the desired safety and efficacy profile despite having progressed through nonclinical studies and initial clinical trials. Further, clinical development in immunology and autoimmune diseases, including pMN, ITP, SLE, and IgAN, presents inherent challenges, such as heterogeneous disease courses, variable endpoints, competition to enroll patients in trials, background therapy effects, and long-duration studies, which may delay or impair our ability to demonstrate clinical benefit and obtain regulatory approval for our product candidates. Regulators may require additional studies, protocol modifications, or changes to endpoints, and guidance from regulators can evolve, which could affect our development plans and timing. Manufacturing scale-up, assay validation, and process comparability for biologics can also delay trials or approvals. Any delays could increase our costs, shorten any effective exclusivity periods we may obtain for a product candidate, and enable competitors to reach the market earlier than us, reducing commercial viability for our product candidates. A number of companies in the biotechnology industry have suffered significant setbacks in advanced clinical trials due to lack of efficacy or emergence of unacceptable safety issues, notwithstanding promising results in earlier trials. Most product candidates that commence clinical trials are never approved and there can be no assurance that any of our future clinical trials will ultimately be successful or support further nonclinical or clinical development of our product candidates. Our success is dependent on the progress and outcomes of our development efforts, including our clinical trials of budoprutug for pMN, ITP and SLE, our clinical trial of the SC formulation of budoprutug, and our clinical trials of CLYM116. In addition, the commencement and rate of completion of nonclinical studies and clinical trials may be delayed by many factors, including: - inability to generate sufficient nonclinical or other in vivo or in vitro data to support the initiation of clinical trials;- nonclinical studies or clinical trials may show a product candidate to be less effective than expected (e.g., a clinical trial could fail to meet its primary endpoint(s)) or have unacceptable side effects or toxicities;- failure to establish clinical endpoints that applicable regulatory authorities would consider clinically meaningful;- delays in reaching 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 clinical trial sites;- delays in identifying, recruiting and training suitable clinical investigators;- differences in trial design between early-stage clinical trials and later-stage clinical trials make it difficult to extrapolate the results of earlier clinical trials to later clinical trials;- delays in reaching a consensus with regulatory authorities on trial design and any nonclinical studies required in support of our product candidates and the potential for a delay in site initiations;- delays in recruiting suitable patients to participate in our clinical trials;- delays in manufacturing, testing, releasing, validating or importing/exporting sufficient stable quantities of our product candidates we may develop for use in nonclinical studies or clinical trials or the inability to do any of the foregoing;- insufficient or inadequate supply or quality of our product candidates or other materials necessary for use in nonclinical studies or clinical trials, or delays in sufficiently developing, characterizing or controlling a manufacturing process suitable for such studies or trials;- imposition of a temporary or permanent clinical hold by regulatory authorities;- developments on trials conducted by competitors for related technology that raise FDA or foreign regulatory authority concerns about risk to patients of the technology broadly, or if the FDA or a foreign regulatory authority finds that the investigational protocol or plan is clearly deficient to meet its stated objectives;- delays in recruiting, screening and enrolling patients and delays caused by patients withdrawing from clinical trials or failing to return for post-treatment follow-up;- difficulty collaborating with patient groups and investigators;- failure by our CROs, other third parties or us to adhere to clinical trial protocols;- failure to perform in accordance with the FDA's or any other regulatory authority's good clinical practices (GCP) or applicable regulatory guidelines in other countries;- occurrence of adverse events associated with any of our product candidates that are viewed to outweigh such product candidate's potential benefits, or occurrence of adverse events in trial of the same class of agents conducted by other companies;- the cost of nonclinical studies and clinical trials of our product candidates being greater than we anticipate;- 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 abandon development of such product candidate;- imposition of a clinical hold by regulatory authorities as a result of a serious adverse event, or after an inspection of trial sites or manufacturing facilities or otherwise;- changes in regulatory requirements and guidance that require amending or submitting new clinical protocols;- transfer of manufacturing processes to larger-scale facilities operated by a third-party CDMO and delays or failure by our CDMOs or us to make any necessary changes to such manufacturing process; and - third parties being unwilling or unable to satisfy their contractual obligations to us. Any inability to successfully initiate or complete nonclinical studies or clinical trials could result in additional costs to us or impair our ability to generate revenue from product sales. Clinical trial delays could also shorten any periods during which our products have patent protection and may allow our competitors to bring products to market before we do, which could impair our ability to successfully commercialize our product candidates and may seriously harm our business. In addition, changes in marketing approval policies during the development period, changes in or the enactment or promulgation of additional statutes, regulations or guidance or changes in regulatory review for each submitted product application, may cause delays in the approval or rejection of an application. For example, in December 2022, with the passage of the Food and Drug Omnibus Reform Act (FDORA), Congress required sponsors to develop and submit a diversity action plan (DAP) for each Phase 3 clinical trial or any other "pivotal study" of a new drug or biological product. These plans are meant to encourage the enrollment of more diverse patient populations in late-stage clinical trials of FDA-regulated products. In June 2024, as mandated by FDORA, the FDA issued draft guidance outlining the general requirements for DAPs. On January 27, 2025, in response to an Executive Order issued by President Trump on January 21, 2025, on Diversity, Equity and Inclusion programs, the FDA removed the draft DAP guidance from its website. Thereafter, following litigation, the FDA restored the draft DAP guidance to the FDA website but stated that "information on this page may be modified and/or removed in the future subject to the terms of the court's order and implemented consistent with applicable law." In light of these ongoing actions, there is considerable uncertainty surrounding the draft DAP guidance and how the FDA will consider DAPs in connection with its review of clinical studies. If we seek to conduct clinical trials in foreign countries or pursue marketing approvals in foreign jurisdictions, we must comply with numerous foreign regulatory requirements governing, among other things, the conduct of clinical trials, manufacturing and marketing authorization, pricing and third-party reimbursement. The foreign regulatory approval process varies among countries and jurisdictions and may include all of the risks associated with FDA approval described above and risks attributable to the satisfaction of local regulations in foreign jurisdictions. Moreover, the time required to obtain approval may differ jurisdiction-to-jurisdiction from that required to obtain FDA approval. Approval by foreign regulatory authorities does not ensure approval by the FDA and, similarly, approval by the FDA does not ensure approval by regulatory authorities outside the U.S. Successful completion of clinical trials is a prerequisite to submitting a marketing application to foreign regulatory authorities or the FDA for each product candidate and, consequently, the ultimate approval and commercial marketing of any product candidate. We may experience negative or inconclusive results, or regulators may be unwilling to accept nonclinical or clinical data obtained in foreign jurisdictions, which may result in our deciding, or our being required by regulators, to conduct additional clinical studies or trials or abandon some or all of our product development programs, which could harm our business. In addition, the FDA and other regulatory authorities' policies with respect to clinical trials may change and additional government regulations may be enacted. 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, and our product development costs may increase if we experience delays in testing or marketing approvals. In addition, if we make manufacturing or other changes to our product candidates, we may need to conduct additional studies to bridge such new formulations to earlier versions. We do not know whether any of our clinical trials will begin as planned, will need to be restructured or will be completed on schedule, or at all. We may also decide to change the design or protocol of one or more of our clinical trials, which could result in delays.

Certain adverse events and undesirable side effects caused by our product candidates could cause us or regulatory authorities to interrupt, delay or pause clinical trials and could result in a more restrictive label or the delay or denial of regulatory approval by the FDA or other comparable foreign regulatory authorities. If undesirable side effects do occur in our future clinical trials they could cause delay or even discontinuance of further development of our product candidates, which would impair our ability to generate revenue and would have a material adverse effect on our business, results of operations, financial condition and cash flows and prospects. As a result of undesirable side effects or further safety issues that we may experience in our clinical trials in the future, we may not receive approval to market our product candidates, which could prevent us from ever generating revenue or achieving profitability. Results of our trials could reveal an unacceptably high severity and prevalence of side effects. In such an event, our trials could be suspended or terminated and the FDA or comparable foreign regulatory authorities could order us to cease further development of, or deny approval of, our product candidates for any or all targeted indications. The drug-related side effects could affect patient recruitment or the ability of enrolled subjects to complete the trial or result in potential product liability claims. Safety signals within APRIL/CD19 classes, including with respect to any products that may compete with our product candidates, could affect regulatory approval, labeling, or market uptake, if approved. Any of these occurrences may have a material adverse effect on our business, results of operations, financial condition and cash flows and prospects. Additionally, if any of our product candidates receive marketing approval, and we, or others, later identify undesirable side effects caused by such product, a number of potentially significant negative consequences could result, including: - we may be forced to suspend marketing of such product;- regulatory authorities may withdraw their approvals of such product;- regulatory authorities may require additional warnings on the label that could diminish the usage or otherwise limit the commercial success of such product;- the FDA or other regulatory bodies may issue safety alerts, Dear Healthcare Provider letters, press releases or other communications containing warnings about such product;- the FDA may require the establishment or modification of a REMS or a comparable foreign regulatory authority may require the establishment or modification of a similar strategy that may, for instance, restrict distribution of our products and impose burdensome implementation requirements on us;- we may be required to change the way the product is administered or conduct additional clinical trials;- we could be sued and held liable for harm caused to subjects or patients;- we may be subject to litigation or product liability claims; and - our reputation may suffer. Any of these events could prevent us from achieving or maintaining market acceptance of the particular product candidate, if approved.