Tango Therapeutics (TNGX) Risk Analysis

As part of our business strategy, we may seek orphan drug designation for certain of our product candidates, and we may be unsuccessful in obtaining such designation. Regulatory authorities in some jurisdictions, including the United States and Europe, 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 a product intended to treat a rare disease or condition, which is generally defined as a patient population of fewer than 200,000 individuals annually in the United States, or a patient population of 200,000 or more in the United States where there is no reasonable expectation that the cost of developing the product will be recovered from sales in the United States. In the United States, orphan drug designation entitles a party to financial incentives such as opportunities for grant funding towards clinical trial costs, tax advantages and user-fee waivers. The FDA granted Orphan Drug Designation to vopimetostat for the treatment of soft tissue sarcoma and of pancreatic cancer, and to TNG456 for the treatment of malignant glioma. Similarly, in the European Union, the European Commission, upon the recommendation of the EMA's Committee for Orphan Medicinal Products, grants orphan designation in respect of products that are intended for the diagnosis, prevention or treatment of life-threatening or chronically debilitating conditions affecting not more than five in 10,000 persons in the European Union and for which no satisfactory method of diagnosis, prevention, or treatment has been authorized (or the product would be a significant benefit to those affected if a method already exists). Additionally, designation may be granted for products intended for the diagnosis, prevention, or treatment of a life-threatening, seriously debilitating or serious and chronic condition and when, without incentives, it is unlikely that sales of the product in the European Union would be sufficient to justify the necessary investment in developing the product. In the European Union, orphan designation entitles a party to financial incentives such as reduction of fees or fee waivers. Generally, if a product with an orphan drug designation subsequently receives the first regulatory 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 the EMA from approving another marketing application for the same product and indication for that time period, except in limited circumstances. The applicable period is seven years in the United States and ten years in the European Union. The exclusivity period in the European Union can be reduced to six years if, at the end of the fifth year, it is established that a product no longer meets the criteria for orphan designation, including where it is shown that the product is sufficiently profitable so that market exclusivity is no longer justified. Obtaining orphan drug exclusivity may not effectively protect a product candidate from competition because different products having different chemical compositions can be approved for the same condition and the same therapies can be approved for different conditions but used off-label. Even after an orphan drug is approved, the FDA can subsequently approve the same product for the same condition if the FDA concludes that the later product is clinically superior in that it is shown to be safer, more effective or makes a major contribution to patient care. In addition, a designated orphan drug may not receive orphan drug exclusivity if it is approved for a use that is broader than the indication for which it received orphan designation. Moreover, orphan drug exclusive marketing rights in the United States may be lost if the FDA later determines that the request for designation was materially defective or if the manufacturer is unable to assure sufficient quantity of the product to meet the needs of patients with the rare disease or condition. Orphan drug designation neither shortens the development time or regulatory review time of a product nor gives the product any advantage in the regulatory review or approval process. While we may seek orphan drug designation for our other product candidates, we may never receive such designations. Even if we do receive such designations, there is no guarantee that we will enjoy the benefits of those designations.

We may seek a breakthrough therapy designation for some of our product candidates. A breakthrough therapy is defined as a drug or biologic 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, and preliminary clinical evidence indicates that the drug or biologic 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 product candidates 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. Product candidates designated as breakthrough therapies by the FDA may also be eligible for rolling review, priority review and accelerated approval. Designation as a breakthrough therapy is within the discretion of the FDA. Accordingly, even if we believe one of our product candidates meets the criteria for designation as a breakthrough therapy, the FDA may disagree and instead determine not to make such designation. In any event, the receipt of a breakthrough therapy designation for a product candidate may not result in a faster development process, review or approval compared to therapies considered for approval under conventional FDA procedures and does not assure ultimate approval by the FDA. In addition, even if one or more of our product candidates qualify as breakthrough therapies, the FDA may later decide that such product candidates no longer meet the conditions for qualification and rescind the designation or decide that the time period for FDA review or approval will not be shortened. If a drug is intended for the treatment of a serious or life-threatening condition and preclinical or clinical data demonstrates the potential to address unmet medical needs for this condition, the 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 withdraw fast track designation if it believes that the designation is no longer supported by data from our clinical development program.

The ongoing success of businesses in the biopharmaceutical industry depends, to a large extent, on the ability to continue to introduce new products, especially as exclusivity rights to approved therapies or in certain indications expire. Research programs to pursue the development of our existing and planned product candidates for new or additional indications and to identify new product candidates and disease targets require substantial technical, financial and human resources whether or not they are ultimately successful. Our target screening technology and research programs may fail to yield potential products for clinical development for a number of reasons, including: ? the research methodology used may not be successful in identifying potential indications and/or product candidates (or the development of a chemical compound or formulation that has the desired safety and efficacy cannot be developed);? potential product candidates may, after further study, be shown to have harmful adverse effects or other characteristics that indicate they are unlikely to be effective products; or ? it may take greater human and financial resources than we possess to identify additional therapeutic opportunities for our product candidates or to develop suitable potential product candidates through internal research programs, thereby limiting our ability to develop, diversify and expand our potential product portfolio. Because we have limited financial and human resources, we intend to initially focus on research programs and product candidates for a limited set of indications. As a result, we may forego or delay pursuit of opportunities of other product candidates or for other indications that later prove to have greater commercial potential or a greater likelihood of success. Our resource allocation decisions may cause us to fail to capitalize on viable commercial products or profitable market opportunities. Accordingly, there can be no assurance that we will ever be able to identify additional therapeutic opportunities for our product candidates or to develop suitable product candidates through internal research programs, which could materially adversely affect our future growth and prospects.

We have not yet demonstrated our ability to complete large-scale, pivotal clinical trials, obtain regulatory approvals, manufacture a commercial scale product or arrange for a third party to do so on our behalf, or conduct sales and marketing activities necessary for successful commercialization. Although we have received FDA clearance of five IND applications (TNG908, vopimetostat, TNG260, TNG348, and TNG456), we have since discontinued development of TNG348 and TNG908. We may not be able to file any future INDs for any of our other product candidates on the timelines we expect, if at all. Further, timelines for developing and filing INDs are subject to significant uncertainties and projected timelines can be delayed. Moreover, we cannot be sure that submission of an IND will result in the FDA allowing clinical trials to begin, or that, once begun, issues will not arise that require us to suspend or terminate clinical trials. Any guidance we receive from the FDA or other regulatory authorities is subject to change. These regulatory authorities could change their position, including on the acceptability of our trial designs or the clinical endpoints selected, which may require us to complete additional clinical trials or result in the imposition of stricter approval conditions than we currently expect. Successful completion of our clinical trials is a prerequisite to submitting an NDA to the FDA, a Marketing Authorization Application, or MAA, to the European Medicines Agency, or EMA, or other marketing applications to regulatory authorities in other jurisdictions, for each product candidate and, consequently, the regulatory approval of each product candidate. While the INDs for TNG908, vopimetostat, TNG260, TNG348, and TNG456 were cleared by the FDA, such clearance does not ensure that an adequate number of patients will be enrolled on a timely basis, or at all or that the clinical trials will be completed on time, or at all. For example, in May 2024, we announced that we were discontinuing development of our TNG348 program due to liver toxicity observed in the dose escalation portion of our Phase 1/2 clinical trial, and in November 2024, we announced that we were discontinuing development of TNG908 to fully resource vopimetostat and TNG456 development. If we are required to conduct additional preclinical studies or clinical trials of our product candidates beyond those that we currently contemplate, if we are unable to successfully complete clinical trials of our product candidates or other testing, if the results of these trials or tests are not positive or are only modestly positive or if there are safety and/or efficacy concerns, we may, among other things: ? be delayed in seeking or obtaining regulatory approval for our product candidates;? not obtain regulatory approval at all;? obtain regulatory approval for indications or patient populations that are not as broad as intended or desired;? be subject to post-marketing testing requirements; or ? have the product removed from the market after obtaining regulatory approval.

The discovery and development of oncology therapeutics for patients with genetically defined or biomarker-driven cancers is a rapidly evolving area, and the scientific discoveries that form the basis for our efforts to discover and develop product candidates are relatively new. Our proprietary functional genomics discovery approach is based on the genetic concept of synthetic lethality. The scientific evidence to support the feasibility of developing product candidates based on these discoveries is both preliminary and limited. Although we believe, based on our preclinical work, that the genetic markers targeted by our programs drive the formation and spread of certain cancers, clinical results may not confirm this hypothesis or may only confirm it for certain alterations or certain tumor types. The patient populations for our product candidates (and our combination clinical trials) are limited to those with specific target alterations and may not be completely defined but are substantially smaller than the general treated cancer population, and we will need to screen and identify these patients with targeted alterations. Successful identification of patients is dependent on several factors, including achieving certainty as to how specific alterations respond to our product candidates and the ability to identify such alterations. Furthermore, even if we are successful in identifying patients with specific targets, we cannot be certain that the resulting patient populations with each mutation will be as large as we anticipate, large enough to allow us to successfully obtain approval for each such mutation and commercialize our product candidates and achieve profitability.

Our preclinical studies, our ongoing clinical trials and future clinical trials may not be successful. It is impossible to predict when or if any of our product candidates will prove effective and safe in humans or will receive regulatory approval. Before obtaining regulatory approval from regulatory authorities for the sale of any product candidate, we must complete preclinical studies and then conduct extensive clinical trials to demonstrate the safety and efficacy of our product candidates in humans. Clinical testing is expensive, difficult to design and implement, can take many years to complete and outcomes are uncertain. A failure of one or more clinical trials can occur at any stage of testing. For example, in May 2024, we announced that we were discontinuing development of our TNG348 program due to liver toxicity observed in the dose escalation portion of our Phase 1/2 clinical trial. The outcome of preclinical development testing and early clinical trials may not be predictive of the success of later clinical trials, and interim or preliminary results of a clinical trial do not necessarily predict final results (or be indicative of safety and efficacy if commercialized and used in a broader population). Moreover, preclinical and clinical data are often susceptible to varying interpretations and analyses, and many companies that have believed their product candidates performed satisfactorily in preclinical studies and clinical trials have nonetheless failed to obtain regulatory approval of their product candidates.

A key component of our strategy includes the use of biomarker testing to guide patient selection for our product candidates and/or target engagement for our product candidates. We rely on third-parties to provide this technology. It is not always the case, however, that the biomarker we have identified for patient selection and/or target engagement is included in a commercially available test offered by biomarker testing providers. If not already commercially available, we may collaborate with biomarker assay development companies for the development of biomarkers associated with our product candidates. We may have difficulty in establishing or maintaining such development relationships, and we will face competition from other companies in establishing these collaborations. There are also several risks associated with biomarker identification and validation. We, in collaboration with any diagnostic partners, may not be able to identify predictive pharmacodynamic biomarkers for one or more of our programs. We may not be able to validate potential biomarkers (e.g., certain genetic mutations) or their functional relevance in relevant in vitro or in vivo models. Data analytics and information from databases that we rely on for identifying or validating some of our biomarker-target relationships may not accurately reflect potential patient populations. Potential biomarkers, even if validated preclinically, may not be functionally effective or validated in human clinical trials. If biomarker assay development companies experience any delays developing and launching the biomarkers we have identified for patient selection and/or target engagement, our clinical trials may be delayed or may not identify sufficient patients to complete the trial and our clinical trials may be unsuccessful and our therapies will not advance to approval.

In connection with the clinical development of our product candidates for certain indications, we may engage third parties to develop or otherwise obtain access to in vitro companion diagnostic tests to identify patient subsets within a disease category who may derive selective and meaningful benefit from our product candidates. Such companion diagnostics may be used during our clinical trials as well as in connection with the commercialization of our products that receive regulatory approval. To be successful, we or our collaborators will need to address a number of scientific, technical, regulatory and logistical challenges in connection with such diagnostic tests. The FDA and comparable foreign regulatory authorities regulate in vitro companion diagnostics as medical devices and, under that regulatory framework, will likely require the conduct of clinical trials to demonstrate the safety and effectiveness of any diagnostics we or third parties may develop, which we expect will require separate regulatory clearance or approval prior to commercialization. We intend to rely on third parties for the design, development and manufacture of companion diagnostic tests for our therapeutic product candidates that may require such tests. If we enter into such collaborative agreements, we will be dependent on the sustained cooperation and effort of our future collaborators in developing and obtaining approval for these companion diagnostics. We must characterize the selectivity, specificity, sensitivity, reproducibility, analytical validation, and clinical validation of companion diagnostics during the development and regulatory approval processes. Moreover, even if data from preclinical studies and early clinical trials appear to support development of a companion diagnostic for a product candidate, data generated in later clinical trials may fail to support the analytical and clinical validation of the companion diagnostic. We and our future collaborators may encounter difficulties in developing, obtaining regulatory clearance or approval for, manufacturing and commercializing companion diagnostics similar to those we face with respect to our therapeutic product candidates themselves, including issues with achieving regulatory clearance or approval, production of sufficient quantities at commercial scale and with appropriate quality standards, and in gaining market acceptance. If we (or any third party we may engage) are unable to successfully develop companion diagnostics for these therapeutic product candidates, or experience delays in doing so, the development and commercialization of these therapeutic product candidates may be adversely affected, these therapeutic product candidates may not obtain regulatory approval, and we may not realize the full commercial potential of any of these therapeutic products that obtain regulatory approval.

From time to time, we may publicly disclose initial, interim or top-line data from our current and future 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, including audit and verification procedures, and as results from additional clinical trial participants become available and trial participants spend additional time on therapy. For example, we may report responses in certain patients that are unconfirmed at the time and which do not ultimately result in confirmed responses to treatment after follow-up evaluations. We may also 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, initial, interim and top-line data should be viewed with caution until the final data are available and fully analyzed. In addition, we may report interim analyses of only certain endpoints rather than all endpoints in a clinical trial. 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 initial or interim data and final data could significantly harm our business prospects and may cause the price of our common stock to fluctuate or decline (and we may be subject to securities litigation that can be costly and time-consuming). Further, regulatory agencies and others 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 adversely impact the potential of the particular program, the likelihood of obtaining regulatory approval of the particular product candidate, the scope of product label, and commercialization of any approved product. In addition, the information we choose to publicly disclose regarding a particular study or clinical trial is derived from information that is typically extensive, and you or others may not agree with what we determine is material or otherwise appropriate information to include in our disclosure. We may from time to time indicate the intent to publicly disclose certain clinical trial data at a future date. We have, for example, noted that in 2026 we will provide a clinical update on the lung cohort of the vopimetostat monotherapy clinical trial and initial data from the Phase 1/2 combination clinical trial with RAS(ON) inhibitors from RevMed. Due to the factors described above, and elsewhere in these Risk Factors, we may be unable to report data on or before the time indicated to investors, we may not have the data to provide the information indicative of safety or efficacy, the data may not be sufficiently mature or the number of patients with a specific histology may be inadequate to draw conclusions about the effectiveness of the therapy, and even if we do provide such clinical trial data, the final results from that phase of the clinical trial may be different from what we disclose initially. If the initial, interim or top-line data that we report differ from final or 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 significantly impaired, which could materially harm our business, operating results, prospects or financial condition. Finally, even if the data provided from the clinical trial is favorable with respect to safety and efficacy, such data may not meet the expectations of our investors and our stock price may decline (and such decline may be material).

We may experience delays in initiating or completing our preclinical studies or clinical trials, including as a result of delays in obtaining, or failure to obtain, the FDA's clearance to initiate clinical trials under future INDs. Additionally, we cannot be certain that preclinical studies or clinical trials for our product candidates will not require redesign, will enroll an adequate number of subjects on time, or will be completed on schedule, if at all. We may experience numerous unforeseen events during, or as a result of, preclinical studies and clinical trials that could delay or prevent our ability to receive regulatory approval or commercialize our product candidates, including the following: ? we may receive feedback from regulatory authorities that require us to modify the design or implementation of our preclinical studies or clinical trials or to delay or terminate a clinical trial;? regulators, IRBs, or ethics committees may delay or may not authorize us or our investigators to commence a clinical trial or conduct a clinical trial at a prospective trial site;? we may experience delays in reaching, or fail to reach, agreement on acceptable terms with prospective trial sites and prospective CROs to conduct our trials, the terms of which can be subject to extensive negotiation and may vary significantly among different trial sites and CROs;? preclinical studies or clinical trials of our product candidates may fail to show safety or efficacy or otherwise produce negative or inconclusive results, and we may decide, or regulators may require us, to conduct additional preclinical studies or clinical trials, or we may decide to abandon product research or development programs;? preclinical studies or clinical trials of our product candidates may not produce differentiated or clinically significant results across tumor types or indications;? the number of patients required for clinical trials of our product candidates may be larger than we anticipate, enrollment in these clinical trials may be slower than we anticipate or we may fail to enroll patients with certain cancer indications, such as pancreatic and lung cancer, that we are focusing on in connection with vopimetostat (and GBM, which is our focus for TNG456), or participants may drop out of these clinical trials or fail to return for post-treatment follow-up at a higher rate than we anticipate;? our third-party contractors may fail to comply with regulatory requirements, fail to maintain adequate quality controls, be unable to provide us with sufficient product supply to conduct or complete preclinical studies or clinical trials, fail to meet their contractual obligations to us in a timely manner, or at all;? our clinical trial sites or investigators 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 in order to ensure our trials generate statistically significant results;? we may elect to, or regulators, IRBs or ethics committees may require us or our investigators to, suspend or terminate clinical research for various reasons, including noncompliance with regulatory requirements or a finding that the participants in our clinical trials are being exposed to unacceptable health risks;? the cost of clinical trials of our product candidates or of our product candidates in combination with other manufacturer's commercial products or product candidates may be greater than we anticipate;? the supply or quality of our product candidates or other materials necessary to conduct clinical trials including our combination clinical trials, of our product candidates (alone or in combination) may be insufficient or inadequate;? our product candidates (or our product candidates in combination with other products or product candidates) may have undesirable side effects or other unexpected characteristics, causing us or our investigators, regulators or IRBs or ethics committees to suspend or terminate the trials, or reports may arise from preclinical or clinical testing of other cancer therapies that raise safety or efficacy concerns about our product candidates;? regulators may revise the requirements for approving our product candidates, (alone or in combination), or such requirements may not be as we anticipate; and ? regulatory developments may occur with respect to our competitors' products, including any developments, litigation or public concern about the safety of such products. We could encounter delays if a clinical trial is suspended or terminated by us, by the IRBs of the institutions at which such trials are being conducted, by the Data Safety Monitoring Board, or DSMB, for such trial or by the FDA or other regulatory authorities. Such authorities may impose such a suspension or termination or clinical hold due to a number of factors, including failure to conduct the clinical trial in accordance with regulatory requirements or our clinical protocols, adverse findings upon an inspection of the clinical trial operations or trial site by the FDA or other regulatory authorities, unforeseen safety issues or adverse side effects, failure to demonstrate a benefit from using a product, changes in governmental regulations or administrative actions or lack of adequate funding to continue the clinical trial. 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 regulatory approval of our product candidates. Further, the FDA may disagree with our clinical trial design or our interpretation of data from clinical trials or may change the requirements for approval even after it has reviewed and commented on the design for our clinical trials. Moreover, principal investigators for our current or future clinical trials have, and in the future may, serve as scientific advisors or consultants to us from time to time and receive compensation in connection with such services. Under certain circumstances, we may be required to report some of these relationships to the FDA or comparable foreign regulatory authorities. The FDA or comparable foreign regulatory authority may conclude that a financial relationship between us and a principal investigator has created a conflict of interest or otherwise affected the interpretation of the study. The FDA or comparable foreign regulatory authority may therefore question the integrity of the data generated at the applicable clinical trial site, and the utility of the clinical trial itself may be jeopardized. This could result in a delay in approval, or rejection, of our marketing applications by the FDA or comparable foreign regulatory authority, as the case may be, and may ultimately lead to the denial of regulatory approval of one or more of our product candidates. Our product development costs will also increase if we experience delays in testing or regulatory approvals. We do not know whether any of our future clinical trials will begin as planned, or whether any of our current or future clinical trials will need to be restructured or will be completed on schedule, if at all. Significant preclinical study or clinical trial delays also could shorten any periods during which we may have the exclusive right to commercialize our product candidates or allow our competitors to bring products to market before we do, which would impair our ability to successfully commercialize our product candidates and may significantly harm our business, operating results, financial condition and prospects.

We may not be able to initiate, continue or complete clinical trials for our product candidates if we are unable to locate and enroll a sufficient number of eligible patients to participate in these trials, including our planned pivotal trial, as required by the FDA or comparable foreign regulatory authorities, or as needed to provide appropriate statistical power for a given trial. In particular, because we are focused on patients with specific genetic mutations for the development of our precision oncology programs and because some of the indications we are pursuing, including pancreatic cancer in connection with vopimetostat and GBM in connection with TNG456, are orphan indications that have small populations, our ability to enroll eligible patients may be limited or may result in slower enrollment than we anticipate. We also may experience slower enrollment as a result of limited trial populations due to clinical trials run by us or our competitors or other factors beyond our control. Delays in enrollment may affect the timing of any results or data announcements from our trials (as well as the timing for dose escalation and dose expansion) and therefore the regulatory approval (if any) for any of our product candidates may extend beyond the period we have targeted or beyond the timeline expected by investors. The patient eligibility criteria defined in our trial protocols, including biomarker-driven identification or the number of prior treatment lines, may limit the patient populations eligible for our clinical trials to a greater extent than competing clinical trials for the same indication that do not have biomarker-driven patient eligibility criteria. We also rely on the willingness and ability of clinicians to screen their patients for biomarkers to indicate which patients may be eligible for enrollment in our clinical trials. In addition, some of our competitors have ongoing clinical trials for product candidates that aim to treat the same indications as our product candidates, and patients who would otherwise be eligible for our clinical trials may choose instead to enroll in clinical trials of our competitors' product candidates (for example, multiple INDs for other companies have been cleared by the FDA for clinical trials of MTA-cooperative PRMT5 inhibitors for the treatment of cancer patients, and such trials have already enrolled patients and those trials are using some of the same clinical trial sites that we use). Further, the target patient population eligible for the vopimetostat and TNG456 clinical trials overlap. In particular, each of these clinical trials has arms that are expected to aim to enroll patients with lung cancer. As a result, our own trials may compete to enroll patients among a limited population and thus each of our own trials may experience delays or limited enrollment or we may be compelled to explore enrollment in new countries to gain access to an expanded patient population. In addition to the competitive clinical trial environment, the eligibility criteria of our clinical trials will further limit the pool of available study participants as we will require that patients have specific characteristics that we can measure to assure their cancer is either severe enough or not too advanced to include them in a study. The process of finding patients may prove costly. We also may not be able to identify, recruit or enroll a sufficient number of patients (or sufficient patients who have limited lines of prior therapy) to complete our clinical studies, including our planned pivotal trial, because of the perceived risks and benefits of the product candidates under study, the availability and efficacy of competing therapies and clinical trials, the proximity and availability of clinical trial sites for prospective patients, and the patient referral practices of physicians. If patients are unavailable or unwilling to participate in our studies for any reason, the timeline for recruiting patients, conducting studies, reporting initial and final trial results and obtaining regulatory approval of potential products may be delayed. Further, if we are unable to identify patients with the targeted genetic mutations for our clinical trials, it could compromise our ability to seek designations under applicable FDA expedited review and development programs, including Breakthrough Therapy Designation and Fast Track Designation (to the extent these are available to us), or otherwise seek to accelerate clinical development and regulatory timelines. Patient enrollment may be affected by other factors, including: ? the severity of the disease under investigation;? the efforts to obtain and maintain patient consents and facilitate timely enrollment in clinical trials;? the ability to monitor patients adequately during and after treatment;? the ability to recruit clinical trial investigators with the appropriate competencies and experience;? reporting of the initial results of any of our clinical trials; and ? factors we may not be able to control, including the impacts of any epidemics or pandemics, which may limit patients, principal investigators or staff or clinical site availability.

Certain of our current product candidates are being administered or may have the potential to be administered in combination with existing standards of care (such as checkpoint inhibitor immunotherapies, chemotherapies, targeted therapies or radiotherapy) or with other classes of therapeutics agents (such as the RAS(ON) multi- and G12D- inhibitors from RevMed with which we are evaluating vopimetostat in combination clinical trials and abemaciclib, with which we plan to evaluate TNG456 in a combination clinical trial). Our ability to develop and ultimately commercialize our current programs and product candidates and any future programs or product candidates for use in combination with other therapies will depend on our ability to access such drugs or biologics on commercially reasonable terms for the clinical trials and their availability for use with our commercialized product, if approved. We have entered into separate clinical collaboration and supply agreements with RevMed, Lilly, and Erasca, under which we plan to conduct combination clinical trials with RevMed's RAS(ON) multi- and G12D-selective inhibitors, Lilly's abemaciclib and Erasca's pan-RAS molecular glue, respectively. Additionally, we have purchased pembrolizumab for use in combination with vopimetostat. Nevertheless, we cannot be certain that current or potential future commercial relationships will continue to provide us with a steady supply of such drugs or biologics on commercially reasonable terms, or at all. Any failure to maintain or enter into new commercial relationships, or the expense of purchasing checkpoint inhibitor immunotherapies or other potential combination or comparator therapies in the market, may delay our development timelines, increase our costs and jeopardize our ability to develop our current product candidates and any future product candidates as commercially viable therapies. If any of these circumstances occur, our business, financial condition, operating results, stock price and commercial prospects may be materially harmed.

We have several ongoing and planned clinical trials testing the safety and efficacy of combination therapies, including: evaluating (i) vopimetostat in multiple different combinations, including with each of RevMed's RAS(ON) multi- and G12D- selective inhibitors, and with pembrolizumab and (ii) TNG456 with abemaciclib. We plan to evaluate vopimetostat with Erasca's pan-RAS molecular glue. The clinical development of combination therapies may be more complex than the development of single agent therapies and generally requires that we are able to describe and demonstrate the contribution of each product to the safety and efficacy of the combination as a whole. This requirement may make the design and conduct of clinical trials more complex (which may cause delays in the trial or require additional data to be collected and analyzed, which, in turn, may limit any patent protection or regulatory exclusivity periods we have to market the product candidate). In addition, we expect this would increase the anticipated costs that we incur in connection with seeking regulatory approval of the combination or in commercializing a combination therapy. Further, the FDA's "combination rule" prohibits the FDA approving a fixed-dose combination product unless each component of a proposed drug product contributes to the claimed effects and the dosage of each component (amount, frequency, duration) is safe and effective for the intended population. This typically requires a clinical factorial study, designed to assess the effects attributable to each drug in the combination product, particularly when the ingredients are directed at the same sign or symptom of the disease or condition. Moreover, the applicable requirements for approval of a combination therapy may differ from country to country. In the event that our product candidates fail to demonstrate sufficient safety and efficacy or establish their contribution to the claimed effects of a combination therapies, we would need to identify alternatives. In the event we are unable to do so or are unable to do so on commercially reasonable terms, our business and prospects would be materially harmed. Moreover, following product approval of a combination therapy, the FDA 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 (which we may be unable to do on reasonable terms, or at all). Moreover, developments related to the other product may impact our clinical trials for the combination as well as our commercial prospects should we receive regulatory approval. Such developments may include changes to the other product's safety or efficacy profile, changes to the availability of the other product, quality, manufacturing and supply issues with respect to the other product, and changes to the standard of care.

Any results from our earlier preclinical studies of our programs or our product candidates may not necessarily be predictive of the results from later preclinical studies and clinical trials. Similarly, even if we are able to complete our planned preclinical studies and clinical trials of our product candidates according to our current development timeline, the results from such preclinical studies and clinical trials of our product candidates may not be replicated in subsequent preclinical studies or clinical trial results. Many companies in the pharmaceutical and biotechnology industries have suffered significant setbacks in late-stage clinical trials after achieving positive results in early-stage development, and we cannot be certain that we will not face similar setbacks. These setbacks have been caused by, among other things, preclinical and other nonclinical findings made while clinical trials were underway, or safety, pharmacokinetic or efficacy observations made in preclinical studies and clinical trials, including previously unreported adverse events. Moreover, preclinical, nonclinical and clinical data are often susceptible to varying interpretations and analyses and many companies that believed their product candidates performed satisfactorily in preclinical studies and clinical trials nonetheless failed to obtain regulatory approval.

Before obtaining regulatory approvals for the commercial sale of any products, we must demonstrate through lengthy, complex and expensive preclinical studies and clinical trials that our product candidates are both safe and effective for use in each target indication. Clinical trials are expensive and can take many years to complete, and outcomes are inherently uncertain. Failure can occur at any time during the clinical trial process. Because our precision oncology programs and our product candidates are in early stages of development, there is a high risk of failure, and we may never succeed in developing marketable products. 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 also may fail to show the desired safety and efficacy profile despite having progressed through nonclinical studies and initial clinical trials. If the results of our current and future preclinical studies and clinical trials are inconclusive with respect to the safety, pharmacokinetics or efficacy of our product candidates, if we do not meet the clinical endpoints with statistical and clinically meaningful significance, or if there are safety concerns associated with our product candidates, we may be prevented from, or delayed in, obtaining regulatory approval for such product candidates. In some instances, there can be significant variability in safety or efficacy results between different clinical trials of the same product candidate due to numerous factors, including changes in trial procedures set forth in protocols, differences in the size and type of the patient populations, changes in and adherence to the clinical trial protocols and the rate of dropout among clinical trial participants. There may be side effects experienced during clinical trials in connection with the use of oncology therapies. Results of our trials could reveal a high and unacceptable severity and prevalence of side effects as a result of the use of our therapy (or due to other factors). In such an event, we could decide to suspend or terminate a trial or program, or 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. 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. Product liability claims can be expensive to defend and result in significant damages and harm to our reputation. While we do have insurance to cover certain product liability claims, including in connection with certain injury during clinical trials, the coverage may not cover all injuries, be sufficient to cover all expenses related to any injury and we may be required to pay damages from our own resources and the amount of such damages may be significant. Further, our product candidates could cause undesirable side effects in clinical trials. If side effects are observed, or if our product candidates have characteristics that are unexpected, we may need to abandon their development or limit development to more narrow uses or subpopulations in which the undesirable side effects or other characteristics are less prevalent, less severe or more acceptable from a risk-benefit perspective. For example, in May 2024, we announced that we were discontinuing development of our TNG348 program due to liver toxicity observed in the dose escalation portion of our Phase 1/2 clinical trial. In addition, our product candidates could cause undesirable side effects that we have not yet observed. Many compounds that initially showed promise in early-stage testing for treating cancer have later been found to cause side effects that prevented further development of the compound. There can be no assurance that any of our current or future clinical trials will ultimately be successful or support further clinical development or regulatory approval of any of our product candidates. Certain of our product candidates are being tested, and future product candidates may be used, in combination with one or more cancer therapies. The uncertainty resulting from the use of our product candidates in combination with other cancer therapies may make it difficult to accurately predict side effects in future clinical trials or the combination product may cause negative effects resulting from drug-drug interactions in clinical trials. As is the case with many treatments for cancer and rare diseases, it is likely that there may be side effects associated with the use of our product candidates. If significant adverse events or other side effects are observed in the clinical trials of our product candidates or when used in combination with another therapy, we may have difficulty recruiting patients to our clinical trials, patients may drop out of our clinical trials, or we may be required to abandon the trials or our development efforts of one or more product candidates altogether. We, the FDA or other applicable regulatory authorities, or an IRB, may suspend or terminate 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. For example, in May 2024, we announced that we were discontinuing development of our TNG348 program due to liver toxicity observed in the dose escalation portion of our Phase 1/2 clinical trial. Even if the side effects do not preclude the monotherapy or the combination products from obtaining or maintaining regulatory approval, undesirable side effects may inhibit market acceptance of the approved combination products due to their tolerability versus other therapies. Any of these developments could materially harm our business, operating results, financial condition and prospects.