Pliant Therapeutics (PLRX) Risk Analysis

We are evaluating PLN-101095 as a monotherapy and in combination with pembrolizumab, a currently approved cancer therapy. The development of product candidates for use in combination with another product or product candidate may present challenges that are not faced for single agent product candidates. The FDA, EMA, or comparable foreign regulatory authorities may require us to use more complex clinical trial designs in order to evaluate the contribution of each product and product candidate to any observed effects. It is possible that the results of such trials could show that any positive previous trial result are attributable to the combination therapy and not our current product candidates and any future product candidates. It is also possible that trial results for our product candidates may differ significantly if our product candidates are investigated with different combination therapies in different trials - for example, if we were to investigate our product candidates with one immunotherapy in one trial and a different immunotherapy in another. Moreover, following product approval, the FDA, EMA, or comparable foreign regulatory authorities may require that products used in conjunction with each other be cross-labeled for combined use. To the extent that we do not have rights to the other product, this may require us to work with a third party to satisfy such a requirement. Further, if third-party patents relating to existing therapies used in combination with our current and future product candidates were to expire, our competitors could develop and commercialize products or technologies similar or identical to ours. For example, several key patents related to pembrolizumab are scheduled to expire in the year 2028. Accordingly, we may be open to increased competition from new single-agent and combination therapy candidates, including therapies that include biosimilars and generics. We are not able to predict what the loss of patent protection for pembrolizumab will have on our prospects or our ability to successfully develop and commercialize our product candidates. Loss of patent protection for pembrolizumab could adversely affect our business, financial condition and prospects. If PLN-101095 or other current or future product candidates were to receive marketing approval or be commercialized for use in combination with other existing therapies, we would also be subject to the risks that the FDA or comparable foreign regulatory authorities could revoke approval of the therapy used in combination with any of our product candidates, or safety, efficacy, manufacturing or supply issues could arise with these existing therapies. It is also possible that the existing therapies with which our product candidates are approved for use could fall out of favor or be relegated to later lines of treatments. Any of the foregoing could result in the need to find other combination therapies for our product candidates or in our own products being removed from the market or being less commercially successful. We may also evaluate PLN-101095 in combination with one or more other cancer therapies that have not yet been approved for marketing by the FDA or comparable foreign regulatory authorities. We will not be able to market and sell PLN-101095 in combination with any such unapproved cancer therapies that do not ultimately obtain marketing approval. If third parties successfully develop and commercialize competitive combination therapies, the FDA or comparable foreign regulatory authorities do not approve or withdraw approval of these other therapies, or if safety, efficacy, commercial adoption, manufacturing, supply or other issues arise with the therapies we choose to evaluate in combination with PLN-101095 or other current or future product candidates, we may be unable to obtain approval of or successfully market PLN-101095 or one or all of the other current or future product candidates we develop. Additionally, if the third party providers of pembrolizumab or other currently approved or in development therapies used in combination with PLN-101095 or other current or future product candidates are unable to produce sufficient quantities for clinical trials or for commercialization of PLN-101095 or our other future product candidates, or if the cost of combination therapies is prohibitive, our development and commercialization efforts would be impaired, which would have an adverse effect on our business, financial condition, results of operation and growth prospects. In the event that any of our collaborators or suppliers cannot continue to supply their products on commercially reasonable terms, we may need to identify alternatives for accessing such immunotherapies. Additionally, should the supply of products from any collaborator or supplier be interrupted, delayed or otherwise be unavailable to us, our clinical trials may be delayed. In the event we are unable to source an alternative supply, or are unable to do so on commercially reasonable terms, our business, financial condition, results of operations, stock price and prospects may be materially harmed.

We are currently conducting a Phase 1 clinical trial of PLN-101095 in solid tumors. We have no products that are approved for commercial sale and may never be able to develop marketable products. If PLN-101095 or any of our other product candidates encounter safety or efficacy problems, development delays, regulatory issues or other problems, our development plans and business would be significantly harmed. For example, in March 2025, we announced that we were discontinuing the BEACON-IPF Phase 2b trial and in June 2025, we announced that we were discontinuing the development of bexotegrast in idiopathic pulmonary fibrosis, or IPF. Before we can generate any revenue from sales of PLN-101095 or any of our other product candidates, we must undergo additional preclinical and clinical development and regulatory review and obtain marketing approval in one or more jurisdictions. In addition, if one or more of our product candidates are approved, we must ensure access to sufficient commercial manufacturing capacity and conduct significant marketing efforts in connection with any commercial launch. These efforts will require substantial investment, and we may not have the financial resources to continue development of PLN-101095 or any of our other product candidates. We may experience setbacks that could delay or prevent regulatory approval of, or the extent of regulatory protection or our ability to commercialize, our product candidates, including: - negative or inconclusive results from our preclinical studies or clinical trials or the clinical trials of others for product candidates similar to ours, leading to a decision or requirement to conduct additional preclinical testing or clinical trials or abandon a program;- product-related side effects experienced by subjects in our clinical trials or by individuals using drugs or therapeutics similar to our product candidates;- delays in submitting investigational new drug, or IND, applications or comparable foreign applications or delays or failure in obtaining the necessary approvals from regulators to commence a clinical trial, or a suspension or termination of a clinical trial once commenced;- conditions imposed by the FDA or comparable foreign authorities regarding the scope or design of our clinical trials;- delays in enrolling subjects in clinical trials, including due to operational challenges, competition with other clinical trials, the effects of health epidemics and pandemics or geopolitical events, such as recent military action against Iran;- high drop-out rates or screening failures of subjects from clinical trials;- inadequate supply or quality of product candidates or other materials necessary for the conduct of our clinical trials;- challenges manufacturing our product candidates to regulatory requirements in a cost effective manner;- greater than anticipated clinical trial costs;- inability to compete with other therapies;- failure to secure or maintain orphan designation in some jurisdictions;- poor efficacy of our product candidates during clinical trials;- unfavorable FDA or other regulatory agency inspection and review of a clinical trial site;- failure of our third-party contractors or investigators to comply with regulatory requirements or otherwise meet their contractual obligations in a timely manner, or at all;- delays and changes in regulatory requirements, policy and guidelines, including the imposition of additional regulatory oversight around clinical testing generally or with respect to our technology in particular; or - varying interpretations of data by the FDA and similar foreign regulatory agencies. We do not have complete control over many of these factors, including certain aspects of clinical development and the regulatory submission process, potential threats to our intellectual property rights and our manufacturing, marketing, distribution and sales efforts or that of any future collaborator.

Regulatory authorities in some jurisdictions, including the United States and other major markets, may designate drugs intended to treat conditions or diseases affecting relatively small patient populations as orphan drugs. Generally, if a product candidate with an orphan drug designation receives the first marketing approval for the indication for which it has such designation, the product is entitled to a period of marketing exclusivity, which precludes the FDA or foreign regulatory authorities from approving another marketing application for a product that constitutes a similar medicinal product treating the same indication for that marketing exclusivity period, except in limited circumstances. The applicable period is seven years in the United States and ten years in the EEA. The exclusivity in the EEA can be reduced to a period of six years if the orphan designation criteria are no longer met after the fifth year, including if the product is sufficiently profitable so that market exclusivity is no longer justified. Proposed amendments to European Union regulations regarding orphan medicines are under consideration which, if approved, could reduce the ten-year marketing exclusivity period. Orphan drug exclusivity may be revoked if any regulatory agency determines that the request for designation was materially defective or if the manufacturer is unable to assure sufficient quantity of the product to meet the needs of patients with the rare disease or condition. Even if we obtain orphan drug exclusivity for a product candidate, that exclusivity may not effectively protect the product candidate from competition because different drugs with different active moieties can be approved for the same condition in the United States or EEA. Even after an orphan drug is approved, the FDA or EMA, as applicable, may subsequently approve another drug with the same active moiety for the same condition if the FDA concludes that the latter drug is not a similar medicinal product or is clinically superior in that it is shown to be safer, more effective or makes a major contribution to patient care.

Our approach to discover and develop integrin-based therapeutics is a novel approach in a rapidly developing field, and there can be no assurance that we will not experience currently unknown problems or delays in developing PLN-101095 or our other product candidates, that such problems or delays will not result in unanticipated costs, or that any such development problems can be solved. As a result, we may never succeed in developing a marketable integrin-based product.

To obtain the requisite regulatory approvals to commercialize any product candidates, we must demonstrate through extensive preclinical studies and clinical trials that our product candidates are safe and effective in humans. Clinical testing is expensive and can take many years to complete, and its outcome is inherently uncertain. In particular, the general approach for FDA approval of a new drug is dispositive data from two well-controlled, Phase 3 clinical trials of the relevant drug in the relevant patient population. Phase 3 clinical trials typically involve hundreds of patients, have significant costs and take years to complete. A product candidate can fail at any stage of testing, even after observing promising signals of activity in earlier preclinical studies or earlier stage clinical trials. The results of preclinical studies and early clinical trials of our product candidates may not be predictive of the results of later-stage clinical trials. For example, in March 2025, we announced that we were discontinuing the BEACON-IPF Phase 2b trial, and in June 2025, that we were discontinuing development of bexotegrast in IPF. In addition, 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 preclinical studies and initial clinical trials. A large number of companies in the biopharmaceutical industry have suffered significant setbacks in advanced clinical trials due to lack of efficacy or unacceptable safety issues, notwithstanding promising results in earlier trials or divergent conclusions by the FDA, other regulatory agencies, institutional review boards, or IRBs, data safety monitoring boards, or DSMBs, or others in connection with such findings. Most product candidates that commence clinical trials are never approved as products and there can be no assurance that any of our future clinical trials will ultimately be successful or support further clinical development of any of our product candidates. Product candidates that appear promising in the early phases of development may fail to reach the market for several reasons, including: - preclinical studies or clinical trials may show the product candidates to be less effective than expected (e.g., a clinical trial could fail to meet its primary endpoint(s)) or to have unacceptable side effects or toxicities;- failure to establish clinical endpoints that applicable regulatory authorities would consider clinically meaningful;- failure to receive the necessary regulatory approvals;- development of competing products in the same disease state;- manufacturing costs, formulation issues, pricing or reimbursement issues, or other factors that make a product candidate uneconomical;- failure or inability to perform by our third-party vendors, including vendors in foreign jurisdictions such as China; and - the proprietary rights of others and their competing products and technologies that may prevent one of our product candidates from being commercialized. In addition, 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. Further, as we rely on novel technologies including sophisticated imaging technologies to generate data relating to our clinical endpoints, there is an increased risk that we may not properly measure, analyze or interpret this data. Moreover, clinical data are often susceptible to varying interpretations and analyses, and many companies that have believed their product candidates performed satisfactorily in clinical trials have nonetheless failed to obtain marketing approval of their products. Additionally, some of our trials are open label studies, 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 typically, open label clinical trials test only the investigational product candidate and sometimes do so at different dose levels. For example, PLN-101095 is currently being evaluated in an ongoing first-in-human Phase 1 dose-escalation open label trial where patients are either receiving PLN-101095 alone or in combination with the immunotherapy pembrolizumab. Open label clinical trials are subject to various limitations that may exaggerate any therapeutic effect as patients in open label clinical trials are aware of when they are receiving 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. Therefore, it is possible that positive results observed in open label trials will not be replicated in later placebo-controlled trials. In addition, the standards that the FDA and comparable foreign regulatory authorities use when regulating us require judgment and can change, which makes it difficult to predict with certainty how they will be applied. Although we are currently focusing our efforts on development of small molecule drug products, if we were to also commence the development of biological products in the future we could be subjected to additional regulatory requirements. Any analysis we perform of data from preclinical and clinical activities is subject to confirmation and interpretation by regulatory authorities, which could delay, limit or prevent regulatory approval. We may also encounter unexpected delays or increased costs due to new government regulations or changes in regulatory policy as a result of judicial challenges. Examples of such regulations and changes include future legislation or administrative action, or changes in FDA policy during the period of product development and FDA regulatory review. It is impossible to predict whether legislative changes will be enacted, or whether FDA or foreign regulations, guidance or interpretations will be changed, or what the impact of such changes, if any, may be. The FDA may also require a panel of experts, referred to as an Advisory Committee, to deliberate on the adequacy of the safety and efficacy data to support approval. The opinion of the Advisory Committee, although not binding, may have a significant impact on our ability to obtain approval of any product candidates that we develop. We must comply with numerous foreign regulatory requirements governing, among other things, the conduct of clinical trials, manufacturing and marketing authorization, and if approved for marketing, pricing and third-party reimbursement. The foreign regulatory approval process varies among countries and may include all of the risks associated with FDA approval described above as well as risks attributable to the satisfaction of local regulations in foreign jurisdictions. Moreover, the time required to obtain approval may differ from that required to obtain FDA approval. Approval by the FDA does not ensure approval by regulatory authorities outside the United States and vice versa. Successful completion of clinical trials is a prerequisite to submitting a marketing application to the FDA and similar marketing applications to comparable foreign regulatory authorities, for each product candidate and, consequently, the ultimate approval and commercial marketing of any product candidates. We may experience negative or inconclusive results, 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 have a material adverse effect on our business.

We may experience delays in initiating or completing clinical trials. We also may experience numerous unforeseen events during, or as a result of, any future clinical trials that could delay or prevent our ability to receive marketing approval or commercialize PLN-101095 or any other product candidates, including: - regulators, IRBs, or ethics committees may not authorize us or our investigators to commence a clinical trial or conduct a clinical trial at a prospective trial site;- the FDA or other comparable regulatory authorities may disagree with our clinical trial design, including with respect to dosing levels and dose selection administered in our planned clinical trials, which may delay or prevent us from initiating our clinical trials with our originally intended trial design or impact our ability to demonstrate favorable safety or efficacy traits;- we may experience delays in reaching, or fail to reach, agreement on acceptable terms with prospective trial sites and prospective contract research organizations, or CROs, which can be subject to extensive negotiation and may vary significantly among different CROs and trial sites;- the number of subjects required for clinical trials of any product candidates may be larger than we anticipate or subjects may drop out of these clinical trials or fail to return for post-treatment follow-up at a higher rate than we anticipate, or we may have enrollment issues due to disruptions related to uncertainty caused by geopolitical events (such as recent military action against Iran) or health pandemics;- our third-party contractors may fail to comply with regulatory requirements or meet their contractual obligations to us in a timely manner, or at all, or may deviate from the clinical trial protocol or drop out of the trial, which may require that we add new clinical trial sites or investigators;- we may experience delays or interruptions to our manufacturing supply chain, or we could suffer delays in reaching, or we may fail to reach, agreement on acceptable terms with third-party service providers on whom we rely;- additional delays and interruptions to our clinical trials could extend the duration of the trials and increase the overall costs to finish the trials as our fixed costs are not substantially reduced during delays;- we may elect to, or regulators, IRBs, DSMBs, or ethics committees may require that we or our investigators suspend or terminate clinical research or trials for various reasons, including noncompliance with regulatory requirements or a finding that the participants are being exposed to unacceptable health risks;- we may not have the financial resources available to begin and complete the planned trials, or the cost of clinical trials of any product candidates may be greater than we anticipate;- the supply or quality of our product candidates or other materials necessary to conduct clinical trials of our product candidates may be insufficient or inadequate to initiate or complete a given clinical trial; and - the FDA or other comparable foreign regulatory authorities may require us to submit additional data such as long-term toxicology studies, or impose other requirements before permitting us to initiate a clinical trial. Our product development costs will increase if we experience additional delays in clinical testing or in obtaining marketing approvals. 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. If we do not achieve our product development goals in the timeframes we announce and expect, the approval and commercialization of our product candidates may be delayed or prevented entirely. In addition, significant clinical trial delays could shorten any periods during which we may have the exclusive right to commercialize our product candidates and may allow our competitors to bring products to market before we do, potentially impairing our ability to successfully commercialize our product candidates and harming our business and results of operations. Any delays in our clinical development programs may harm our business, financial condition, and results of operations significantly.

If significant adverse events or other side effects are observed in any of our ongoing or future clinical trials, we may have difficulty recruiting patients to our clinical trials, patients may drop out of our trials, or we may be required to abandon the trials or our development efforts altogether. For example, in March 2025, we announced that we were discontinuing the BEACON-IPF Phase 2b trial following a prespecified data review and recommendation by the trial's independent DSMB, as well as a secondary review and recommendation by an outside expert panel due to an imbalance in safety events between treatment and placebo groups. We subsequently announced in June 2025 that we were discontinuing development of bexotegrast in IPF. We may also encounter unexpected drug-drug interactions in our ongoing or planned trials, and may be required to further test our candidates, including additional drug-drug interaction studies, which may be expensive, time consuming and result in delays to our programs. Some potential therapeutics developed in the biopharmaceutical 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 the product candidate from obtaining or maintaining marketing approval, undesirable side effects may inhibit market acceptance of the approved product due to its tolerability versus other therapies.