DSGN 10-K & 10-Q changes, risk factors and insider trading

We are a clinical-stage biopharmaceutical company with a limited operating history that may make it difficult to evaluate the success of our business to date and to assess our future viability. Our operations to date have been limited to business planning, organizing and staffing our company, raising capital, developing and optimizing our technology platform, identifying potential product candidates, undertaking research and nonclinical studies for our lead program in FA and our other development programs, early clinical development for our FAFA, FECD and FECDDM1 programs, establishing and enhancing our intellectual property portfolio, and providing general and administrative support for these operations. As a result, none of our product candidates have been approved for commercial sale. We have never generated any revenue from product sales and have incurred net losses each year since we commenced operations, including a net loss of $49.6$69.8 million and $66.9$49.6 million for the years ended December 31, 20242025 and 2023,2024, respectively. We expect that it will be several years, if ever, before we have a product candidate ready for regulatory approval and commercialization. We expect to incur increasing levels of operating losses over the next several years and for the foreseeable future as we advance our product candidates through clinical development. Our prior losses, combined with expected future losses, have had and will continue to have an adverse effect on our stockholders’ equity and working capital.

the cost, timing and outcome of seeking FDA, European Medicines Agency (EMA)Commission and any other regulatory approvals for any product candidates;

Because we do not expect to generate revenue from product sales for many years, if at all, we will need to obtain substantial additional funding in connection with our continuing operations and expected increases in expenses. Until such time as we can generate significant revenue from sales of our product candidates, if ever, we expect to finance our cash needs through equity offerings, debt financings or other capital sources, including potential collaborations, licenses or other similar arrangements. In addition, we may seek additional capital due to favorable market conditions or strategic considerations, even if we believe we have sufficient funds for our current or future operating plans. Our ability to raise additional funds may be adversely impacted by potential worsening global economic conditions and disruptions to and volatility in the credit and financial markets in the United States and worldwide as a result of macroeconomic factors, including geopolitical conflicts (such as the geopolitical tensions between the U.S. and China, the ongoing Russia/Ukraine conflict and the Israel-Hamas war),conflicts, inflation, tariffs, other fiscal and trade policy changes, bank failures, global supply chain and labor shortage challenges, and the effects of a health epidemic or pandemic. If we are unable to raise capital when needed or on attractive terms, we would be forced to delay, reduce or eliminate our research and development programs or future commercialization efforts.

We are early in our development efforts andwith we have only twothree product candidates in clinical development,development and with all of our other research programs currently in the nonclinical or discovery stage. We have a limited history of conducting clinical trials to test our product candidates in humans.

We are early in our development efforts and most of our operations to date have been limited to developing our platform technologies and conducting drug discovery and nonclinical studies.efforts. Our lead FA GeneTAC® small molecule, DT-216, formulated as the prior DT-216 product candidate,candidate (DT-216P1), entered into a Phase 1 SAD clinical trial in March 2022, the first clinical trial for one of our product candidatescandidates, and we completed the Phase 1 MAD clinical trial of the prior DT-216 product candidateDT-216P1 in August 2023. We withdrew our IND for the prior DT-216 product candidateDT-216P1 in October 2023, and have initiatedcompleted dosing in a Phase 1 SAD clinical trial inwith normal healthy volunteers in Australia to evaluate single doses using multiple routes of administration of DT-216P2, which uses the same drug substance, DT-216. We are conducting our RESTORE-FA Phase 1/2 MAD clinical trial of DT-216P2 and have also completed dosing in a Phase 1 clinical trial inwith normal healthy volunteers for DT-168, our FECD GeneTAC® product candidate. AsFurthermore, we are conducting a result,Phase 2 biomarker trial of DT-168 to evaluate safety, tolerability, and corneal endothelium biomarkers in patients with FECD. In the fourth quarter of 2025, we obtained regulatory clearance to initiate clinical development of DT-818, our DM1 GeneTAC® product candidate. We have initiated dosing in a Phase 1 MAD trial with normal healthy volunteers and plan to begin dosing DM1 patients in the first half of 2026. The study, with results anticipated in 2027, is expected to assess safety and correction of mis-splicing. We have limited infrastructure, experience conducting clinical trials as a company and regulatory interactions, and cannot be certain that our clinical trials will be completed on time, if at all, that our planned development programs would be acceptable to the FDA or other comparable foreign regulatory authorities, or that, if approval is obtained, such product candidates can be successfully commercialized.

Clinical drug development is expensive and can take many years to complete, and its outcome is inherently uncertain. Failure or delay can occur at any time during the drug development process, including due to factors outside of our control. Success in nonclinical testing and early clinical trials does not ensure that later clinical trials will be successful. A number of companies in the pharmaceutical industry, including biotechnology companies, have suffered significant setbacks in clinical trials, even after having promising results in earlier nonclinical studies or clinical trials. These setbacks have been caused by, among other things, nonclinical findings emerging while clinical trials were underway and safety or efficacy observations made in nonclinical studies or clinical trials, including previously unreported adverse events. Although we have initiated clinical trials of DT-216P2, conducted clinical trials of the prior DT-216 product candidate and nonclinical studies of the prior DT-216 product candidate and DT-216P2 for the treatment of patients with FA, completed dosing in a Phase 1 clinical trial of DT-168 in normal healthy volunteers and conducted certain nonclinical studies of DT-216P2, DT-168 and DT-818, and conducted clinical trials and nonclinical studies of DT-216P1 and certain nonclinical studies of other potential product candidates targeting expansion repeat driven diseases, we do not know whether DT-216P2DT-216P2, DT-168, or DT-168DT-818 or other potential product candidates targeting expansion repeat driven diseases will perform in ongoing or future clinical trials as they have performed in prior studies. Furthermore, for some indications that we are pursuing, such as FECD caused by a nucleotide repeat expansion mutation in the TCF4 gene, there are no animal models of the human disease and therefore our ability to predict human disease outcomes may be reduced.

While we have conducted nonclinical studies of the prior DT-216 product candidateDT-216P1 for the treatment of patients with FA, released initial clinical data from our Phase 1 SAD clinical trial in December 2022 and released initial results from the Phase 1 MAD clinical trial of the prior DT-216 product candidateDT-216P1 in August 2023 with results showing that DT-216 was generally well-tolerated and exhibited the ability to overcome the FXN transcription impairment that causes FA, previously reported resultsdata from the Phase 1 SAD clinical trial showed that three patients on the prior DT-216 product candidate had injection site thrombophlebitis that were mild or moderate and resolved without treatment. DT-216 was generally well-tolerated in the Phase 1 MAD clinical trial.trial However,for DT-216P1 suggests more sustained exposure to DT-216 is likely needed to achieve a more durable increase in FXN expression and self-limited thrombophlebitis at the injection site thrombophlebitis was observed in five patients across all three dose levels (100 mg, 200 mg and 300 mg), in the Phase 1 MAD clinical trial of DT-216P1, whereas thrombophlebitis at the injection site thrombophlebitis was only observed at higher doses (the 400 mg and 600 mg cohorts) in the Phase 1 SAD clinical trial.trial of DT-216P1. Nonclinical studies showed that the thrombophlebitis at the injection site reactions werewas attributable to the formulation excipients in the prior DT-216DT-216P1 product candidate formulation, and that improving the formulation composition could improve exposure, enable higher doses and chronic administration. We have since shown that a potentially improved formulation using a novel and proprietary excipient with DT-216P2 had improved properties, including favorable injection site tolerabilitytolerability, following multiple intravenous administrations and enabled dosing to increase tissue exposure. Given the injectionpotential sitebenefits of improved exposure, thrombophlebitis observed in the Phase 1 MAD clinical trial of DT-216P1 and concern for potential worsening of thrombophlebitis at the injection site thrombophlebitis at higher doses with multiple administration, and the initial results from animal studies using a novel and proprietary excipient in DT-216P2, instead of advancing the prior DT-216 product candidateDT-216P1 through to Phase 2 in the second half of 2023 as originally planned, we decided to pursue development of DT-216P2 to better support the future clinical development and regulatory pathway for the drug substance DT-216. We withdreware conducting our IND for the prior DT-216 product candidate in October 2023. We have initiated aRESTORE-FA Phase 1/2 SADMAD clinical trial of DT-216P2DT-216P2. inThe normalRESTORE-FA healthytrial volunteersis in Australiadesigned to evaluate singlethe dosessafety, usingtolerability, multiplePK routesand PD of administration, specifically IV infusion and SCsubcutaneous injection and infusion routes. Results from this Phase 1 SAD clinical trial will inform the designadministration of a clinical trialDT-216P2 in FApatients patients,with anticipated to begin in mid-2025.FA. We anticipate providing an update infrom 2026the RESTORE-FA trial on the effect of DT-216P2 on endogenous FXNfrataxin levels following 12 weeks of dosing.dosing in the second half of 2026. We believe the thrombophlebitis at the injection site seen with DT-216P1 is no longer an issue limiting continued development of DT-216. However, there can be no assurance that we will be able to successfully develop DT-216P2 with improved properties, including favorable injection site tolerability and the absence of other unacceptable side effects on the timeframe we expect, or at all, or that we will be able to achieve our anticipated timeline for resumed Phase 1 clinical development and data.data timelines for the RESTORE-FA trial. In addition, in June 2025, we received a clinical hold notice from the FDA regarding our IND for DT-216P2. In December 2025, the clinical hold was lifted and we received clearance from the FDA to initiate clinical studies for DT-216P2.

obtaining institutional review board (IRB) approval or positive Ethics Committee opinion at each site;

We could also encounter delays if a clinical trial is suspended or terminated by us, by the IRBs or Ethics Committee of the institutions in which such trials are being conducted, by a Data Safety Monitoring Board (DSMB) for such trial or by the FDA or other regulatory authorities (including foreign regulatory authorities comparable to the FDA). Such authorities may suspend or terminate a clinical trial due to a number of factors, including failure to conduct the clinical trial in accordance with regulatory requirements or our clinical protocols, inspection of the clinical trial operations or trial site by the FDA or other regulatory authorities resulting in the imposition of a clinical hold, unforeseen safety issues or adverse side effects, failure to demonstrate a benefit from using a drug, changes in governmental regulations or administrative actions or lack of adequate funding to continue the clinical trial.

The clinical trial requirements of the FDA, EMAthe European Union and other comparable foreign regulatory agencies and the criteria these regulators use to determine the safety and efficacy of a product candidate vary substantially according to the type, complexity, novelty and intended use and market of the potential products. The regulatory approval process for novel product candidates such as ours can be more expensive and take longer than for other, better known or extensively studied pharmaceutical or other product candidates.

We may not be able to continue our ongoing clinical trials or initiate or continue clinical trials planned in the future for our product candidates if we are unable to identify and enroll a sufficient number of eligible patients to participate in these trials as required by the FDA.FDA or comparable foreign regulatory authorities. Patient enrollment, a significant factor in the timing of clinical trials, is affected by many factors including the size and nature of the patient population, the proximity of patients to clinical sites, the eligibility criteria for the clinical trial, the design of the clinical trial, competing clinical trials and clinicians’ and patients’ perceptions as to the potential advantages of the product candidate being studied in relation to other available therapies, including any new drugs that may be approved for the indications we are investigating.

In addition, our clinical trials may compete with other clinical trials for product candidates that are in the same therapeutic areas as our product candidates, and this competition may reduce the number and types of patients available to us, because some patients who might have opted to enroll in our trials may instead opt to enroll in a trial being conducted by one of our competitors. We may also experience enrollment challenges if patients that would otherwise enroll in our trial choose not to do so, or are not eligible to do so, as a result of treatment with another drug. For example, the FDA approved omaveloxolone for the treatment of FA in adults and adolescents aged 16 years and older in February 2023, and omaveloxolone was commercially launched in June 2023. The commercial availability of omaveloxolone may impact future enrollment of our planned clinical trials. FA patients receiving omaveloxolone may be ineligible to enroll in a clinical trial for DT-216P2 or may choose not to do so due to the availability of an approved product. Furthermore, patients enrolled in our clinical trials may receive omaveloxolone and we cannot predict the impact of potential drug interactions on trial results. Likewise, patient enrollment for our planned Phase 1 MAD study of DT-818 may be adversely impacted by competition from clinical trials for other DM1 treatments. Delays in patient enrollment may result in increased costs or may affect the timing or outcome of our clinical trials, which could prevent completion of these trials and adversely affect our ability to advance the development of our product candidates.

We are conducting and plan to conduct additional clinical trials for our product candidates outside the United States and the FDA may not accept data from such trials.

We are conducting and plan to conduct additional clinical trials outside the United States. Although the FDA may accept data from clinical trials conducted outside the United States, acceptance of such study data by the FDA is subject to certain conditions. For example, the clinical trial must be conducted in accordance with Good Clinical Practices (GCP) requirements and the FDA must be able to validate the data from the clinical trial through an onsite inspection if it deems such inspection necessary.

There can be no assurance the FDA will accept data from clinical trials conducted outside of the United States. If the FDA does not accept any such data, it would likely result in the need for additional clinical trials, which would be costly and time-consuming and delay aspects of our development plan. In addition, the conduct of clinical trials outside the United States could have a significant impact on us. Similar considerations regarding the conduct of clinical trials in foreign countries apply abroad. Risks inherent in conducting international clinical trials include:

Undesirable side effects caused by our product candidates could cause us or regulatory authorities to interrupt, delay or halt ongoing or planned clinical trials and could result in a more restrictive label or the delay or denial of regulatory approval by the FDA or comparable foreign regulatory authorities. Results of our clinical trials or nonclinical studies could reveal a high and unacceptable severity and prevalence of side effects or unexpected characteristics. For example, we reported data for DT-216P1 from a Phase 1 SAD clinical trial in December 2022 and a Phase 1 MAD clinical trial in August 2023. Both studies showed that DT-216 was generally well-tolerated and exhibited the ability to overcome the FXN transcription impairment that causes FA. Data from the Phase 1 MAD clinical trial for DT-216P1 suggests more sustained exposure to DT-216 is likely needed to achieve a more durable increase in FXN expression and self-limited thrombophlebitis at the injection site was observed in five patients across all three dose levels (100 mg, 200 mg and 300 mg) in the Phase 1 MAD clinical trial of DT-216P1. Nonclinical studies showed that the thrombophlebitis at the injection site was attributable to the formulation excipients in the DT-216P1 formulation, and that improving the formulation composition could improve exposure, enable higher doses and chronic administration. We have since shown that a potentially improved formulation using a novel and proprietary excipient with DT-216P2 had improved properties, including favorable injection site tolerabilitytolerability, following multiple intravenous administrations and enabled dosing to increase tissue exposure. Given the injectionpotential sitebenefits of improved exposure, thrombophlebitis observed in the Phase 1 MAD clinical trial for DT-216P1 and concern for potential worsening of thrombophlebitis at the injection site thrombophlebitis at higher doses with multiple administration,administration and the initial results from animal studies with DT-216P2 using a novel and proprietary excipient, instead of advancing the prior DT-216 product candidate with the current formulationDT-216P1 through to Phase 2 in the second half of 2023 as originally planned, we decided to pursue development of DT-216P2 that we believe may better support the future clinical development and regulatory pathway for the drug substance DT-216. WeBased withdrewon ourearly INDclinical fordata and non-clinical studies of DT-216P2, we believe the priorthrombophlebitis DT-216at productthe candidateinjection insite Octoberseen 2023.with WeDT-216P1 haveis initiatedno alonger Phasean 1issue SADlimiting clinicalcontinued trialdevelopment of DT-216P2 in normal healthy volunteers in Australia to evaluate single doses using multiple routes of administration, specifically IV infusion and SC injection and infusion routes. Results from this Phase 1 SAD clinical trial will inform the design of a clinical trial in FA patients, anticipated to begin in mid-2025. We anticipate providing an update in 2026 on the effect of DT-216P2 on endogenous FXN levels following 12 weeks of dosing.DT-216. However, there can be no assurance that we will be able to successfully develop DT-216P2 with improved properties, including favorable injection site tolerability and the absence of other unacceptable side effects on the timeframe we expect, or at all, or that we will be able to achieve our anticipated timeline for resumed Phase 1 clinical development and data.data timelines.

If unacceptable side effects, such as thrombophlebitis at the injection site or other severe injection site reactions associated with intravenous administrationor (includingsubcutaneous injection site thrombophlebitis),administration, arise in the development of our product candidates, we, the FDA or comparable foreign regulatory authorities, the IRBs at the institutions in which our studies are conducted, or the DSMB (or applicable safety oversight committee) could recommend a protocol amendment, suspend or terminate our clinical trials or the FDA or comparable foreign regulatory authorities may 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. In addition, these side effects may not be appropriately recognized or managed by the treating medical staff. We expect to have to train medical personnel using our product candidates to understand the side effect profiles for our clinical trials and upon any commercialization of any of our product candidates. Inadequate training in recognizing or managing the potential side effects of our product candidates could result in patient injury or death. Any of these occurrences may harm our business, financial condition and prospects significantly.

Interim,Early, interim, topline and preliminary data from our nonclinical studies or clinical trials that we announce or publish from time to time may change as more patient data become available and are subject to audit and verification procedures that could result in material changes in the final data.

From time to time, we may publicly disclose early, interim, preliminary or topline data from our nonclinical studies or clinical trials, which is based on a preliminary analysis of then-available data, and the results and related findings and conclusions are subject to change following a more comprehensive review of the data related to the particular study or trial. We 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, the early, interim, topline or preliminary results that we report may differ from future results of the same studies, or different conclusions or considerations may qualify such results, once additional data have been received and fully evaluated. Interim,Early, interim, topline and preliminary data also remain subject to audit and verification procedures that may result in the final data being materially different from the preliminary data we previously published. As a result, such data should be viewed with caution until the final data are available. From time to time, we may also disclose early or interim data from our clinical trials. Interim,Early, interim, topline, or preliminary 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 early, preliminary, interim or topline data and final data could significantly harm our business prospects.

Further,In addition, others, including regulatory agencies, may not accept or agree with our assumptions, estimates, calculations, conclusions or analyses or may interpret or weigh the importance of data differently, which could impact the value of the particular program, the approvability or commercialization of the particular product candidate or product and our company in general. In addition, the information we choose to publicly disclose regarding a particular study or clinical trial is based on what is typically extensive information, and you or others may not agree with what we determine is the material or otherwise appropriate information to include in our disclosure, and any information we determine not to disclose may ultimately be deemed significant with respect to future decisions, conclusions, views, activities or otherwise regarding a particular product, product candidate or our business. If the early, interim, topline or preliminary data that we report differ from actual results, or if others including regulatory authorities, disagree with the conclusions reached, our ability to obtain approval for, and commercialize, our product candidates may be harmed, which could harm our business, operating results, prospects or financial condition.

The development, research, testing, manufacturing, labeling, approval, selling, import, export, marketing, promotion and distribution of drug products are subject to extensive and evolving regulation by federal, state and local governmental authorities in the United States, principally the FDA, and by foreign regulatory authorities, which regulations differ from country to country. Neither we nor any future collaborator is permitted to market any of our product candidates in the United States until we receive regulatory approval of an NDA from the FDA. Similar requirements for approval apply to market product candidates in foreign countries.

Obtaining regulatory approval of an NDANDA, or a comparable foreign regulatory approval, can be a lengthy, expensive and uncertain process. Prior to obtaining approval to commercialize a product candidate in the United States or abroad, we or our collaborators must demonstrate with substantial evidence from well-controlled clinical trials, and to the satisfaction of the FDA or other foreign regulatory agencies,authorities, that such product candidates are safe and effective for their intended uses. The number of nonclinical studies and clinical trials that will be required for FDA or foreign regulatory approval varies depending on the product candidate, the disease or condition that the product candidate is designed to address, and the regulations applicable to any particular product candidate.

Results from nonclinical studies and clinical trials can be interpreted in different ways. Even if we believe the nonclinical or clinical data for our product candidates are promising, such data may not be sufficient to support approval by the FDA and other regulatory authorities. Administering product candidates to humans may produce undesirable side effects, which could interrupt, delaydelay, vary or halt clinical trials and result in the FDA or other regulatory authorities denying approval of a product candidate for any or all indications. The FDA and other regulatory authorities may also require us to conduct additional studies or trials for our product candidates either prior to or post-approval, such as additional drug-drug interaction studies or safety or efficacy studies or trials, or it may object to elements of our clinical development program such as the number of subjects in our clinical trials from the United States.States or another country.

The FDA or any foreign regulatory bodiesauthorities can delay, limit or deny approval of our product candidates or require us to conduct additional nonclinical or clinical testing or abandon a program for many reasons, including:

the FDA or the applicable foreign regulatory agency’sauthority's disagreement with the design or implementation of our clinical trials;

negative or ambiguous results from our clinical trials or results that may not meet the level of statistical significance required by the FDA or comparable foreign regulatory agenciesauthorities for approval;

our inability to demonstrate to the satisfaction of the FDA or the applicable foreign regulatory bodyauthority that our product candidates are safe and effective for the proposed indication;

the FDA’s or the applicable foreign regulatory agency’sauthority's disagreement with the interpretation of data from nonclinical studies or clinical trials;

the FDA’s or the applicable foreign regulatory agency’sauthority's requirement for additional nonclinical studies or clinical trials;

the FDA’s or the applicable foreign regulatory agency’sauthority's disagreement regarding the formulation, labeling and/or the specifications of our product candidates;

the FDA’s or the applicable foreign regulatory agency’sauthority's failure to approve the manufacturing processes or facilities of third-party manufacturers with which we contract; or the potential for approval policies or regulations of the FDA or the applicable foreign regulatory agencies to significantly change in a manner rendering our clinical data insufficient for approval.

Even if we eventually complete ongoing and planned clinical testing and receive approval of an NDA or foreign marketing application for our product candidates, the FDA or the applicable foreign regulatory agencyauthority may grant approval contingent on the performance of costly additional clinical trials, including Phase 4 clinical trials, and/or in the case of the FDA, the implementation of a Risk Evaluation and Mitigation Strategy (REMS), which may be required to ensure safe use of the drug after approval. The FDA or the applicable foreign regulatory agencyauthority may also approve a product candidate for a more limited indication or a narrower patient population than we originally requested, and the FDA or applicable foreign regulatory agencyauthority may not approve the labeling that we believe is necessary or desirable for the successful commercialization of a product candidate. Any delay in obtaining, or inability to obtain, applicable regulatory approval would delay or prevent commercialization of that product candidate and would materially adversely impact our business and prospects.

risk that participants enrolled in our clinical trials will acquire an infectious disease while the clinical trial is ongoing, which could impact the results of the clinical trial, including by increasing the number of observed adverse events; and refusal of the FDA or comparable foreign regulatory authorities to accept data from clinical trials in affected geographies outside of their respective jurisdictions.

We may seek orphan drug designation for our product candidates from the FDA and/or from the EMAEuropean Commission in the future. However, we may be unsuccessful in obtaining or may be unable to maintain the benefits associated with orphan drug designation, including the potential for market exclusivity.

We may seek orphan drug designation for our product candidates in the future; however, we may be unsuccessful. Regulatory authorities in some jurisdictions, including the United States and the European Union (EU), may designate drugs for relatively small patient populations as orphan drugs. Under the U.S. Orphan Drug Act, the FDA may designate a drug as an orphan drug if it is a drug 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 greater than 200,000 in the United States where there is no reasonable expectation that the cost of developing the drug will be recovered from sales in the United States. In the EU, the European Commission may grant orphan designation after receiving the opinion of the European Medicine Agency’s (EMA’s) Committee for Orphan Medicinal Products mayprovided grantthat orphanit drugcan designationbe toestablished promotethat the developmentmedicinal ofproduct products that areis intended for the diagnosis, prevention or treatment of a life-threatening or chronically debilitating condition, providedand that the condition is affectingaffects not more than five in 10,000 persons in the EU when the application is made or if,that without incentives,incentives derived from orphan status, it is unlikely that marketing of the drug in the EU would generate sufficient returns to justify the investment needed to develop the drug, and no satisfactory method of diagnosis, prevention or treatment of the condition exists (or, if such a method exists, the drug must be of significant benefit to patients). There can be no assurance that the FDA or EMAEuropean Commission will grant orphan designation for any indication for which we apply, or that we will be able to maintain such designation.

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. If a product candidate with an orphan drug designation subsequently receives the first marketing approval for the indication for which it has such designation, the product is entitled to a period of orphan drug exclusivity, which precludes the EMA or the FDA from approving another marketing application for the same drug or biologic for that time period, except in limited circumstances, such as a showing of clinical superiority to the product with orphan drug exclusivity or where the manufacturer is unable to assure sufficient product quantity. The applicable market exclusivity period is ten years in Europe,the butEuropean suchUnion. During this period, the EMA cannot accept another marketing authorization application or accept an application to extend for a similar product and the European Commission cannot grant a marketing authorization for the same indication for a period of ten years. The period of market exclusivity may be extended by two years for orphan medicinal products that have also complied with an agreed Pediatric Investigation Plan. The period canof market exclusivity may, however, be reduced to six years ifif, aat the end of the fifth year, it is established that the product no longer meets the criteria for orphan designation or if the product is sufficiently profitable so that maintenance of market exclusivity is no longer justified. 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 drug to meet the needs of patients with the rare disease or condition.

Even if we obtain orphan drug exclusivity for a product, that exclusivity may not effectively protect the product from competition because different products can be approved for the same condition. Even after an orphan drug is approved, the FDA or comparable foreign regulatory authority can subsequently approve the same active moiety in a new drug for the same condition if such regulatory authority concludes that the later drug is clinically superior if it is shown to be safer, more effective or makes a major contribution to patient care. Orphan drug exclusivity may also be lost if the FDA later determines that the initial request for designation was materially defective. Additionally, in the EU, a marketing authorization may be granted to a similar medicinal product with the same orphan indication during the 10 year period if: (i) the applicant consents to a second original orphan medicinal product application, (ii) the manufacturer of the original orphan medicinal product is unable to supply sufficient quantities; or (iii) the second applicant can establish that its product, although similar, is safer, more effective or otherwise clinically superior to the original orphan medicinal product.

In addition, orphan drug exclusivity does not prevent the FDA or comparable foreign regulatory authorities from approving competing drugs for the same or similar indication containing a different active ingredient. In addition, if a subsequent drug is approved for marketing for the same or a similar indication as any of our product candidates that receive marketing approval, we may face increased competition and lose market share regardless of orphan drug exclusivity. Orphan drug designation neither shortens the development time or regulatory review time of a drug nor gives the drug any advantage in the regulatory review or approval process.

Any Breakthrough Therapy designation that we may receive from the FDAFDA, or designations in foreign countries, for our product candidates may not lead to a faster development or regulatory review or approval process, and it does not increase the likelihood that our product candidates will receive marketing approval.

We may seek Breakthrough Therapy designation for some of our product candidates. A Breakthrough Therapy is defined as a drug that is intended, alone or in combination with one or more other drugs, to treat a serious or life-threatening disease or condition, and preliminary clinical evidence indicates that the drug may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints. For drugs that have been designated as a Breakthrough Therapy, 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. Drugs designated as a Breakthrough Therapy by the FDA are also eligible for 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. We cannot be sure that any evaluation we may make of our product candidates as qualifying for Breakthrough Therapy designation will meet the FDA’s expectations. 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 drugs 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 a Breakthrough Therapy, the FDA may later decide that such product candidates no longer meet the conditions for qualification or decide that the time period for FDA review or approval will not be shortened. Similarly, the EMA has established the PRIME scheme to expedite the development and review of product candidates that show a potential to address to a significant extent an unmet medical need, based on early clinical data.

In February 2023, the FDA approved omaveloxolone, a Nrf2 activator, for the treatment of FA in adults and adolescents aged 16 years and older and omaveloxolone was commercially launched by Reata Pharmaceuticals in June 2023. Reata Pharmaceuticals was acquired by Biogen in September 2023. We are also aware of a number of companies with active clinical-stage FA programs including (i) Larimar Therapeutics evaluating CTI-1601, a cell penetrating peptide FXN recombinant fusion protein, (ii) Lexeo Therapeutics evaluating a cardiac targeted FXN gene therapy, (iii) Minoryx Therapeutics evaluating leriglitazone, a PPAR-gamma agonist, and (iv) PTC Therapeutics evaluating vatiquinone, a 15-lipoxygenase inhibitor.inhibitor, and (v) Solid Biosciences evaluating a recombinant AAV-based gene replacement therapy. In addition, several companies have stated that they have preclinical gene therapy programs for FA including Astellas Pharma Inc, Capsida Biotherapeutics, SolidPapillon Biosciences,Therapeutics and Voyager Therapeutics.

We are aware of a number of companies with active clinical-stage FECD programs including (i) Aurion Biotech evaluating Vyznova,a expandedcombination cell therapy comprised of donor cells forand transplant,a Rho kinase inhibitor, (ii) Emmecell evaluating donor cornea endothelial cells delivered through magnetic nanoparticles injected into the anterior chamber, (iii) Kowa Pharmaceutical evaluating Ripasudil, a Rho-kinaseRho kinase inhibitor, for use in conjunction with corneal surgery, (iv) Santen Pharmaceutical evaluating STN1010904Sirolimus (licensed from ActualEyes Inc.), an mTOR inhibitor, and (v) Trefoil Therapeutics evaluating TTHX1114, an engineered FGF1 delivered via intracameral injection, for use in conjunction with corneal surgery.

We are aware of a number of programs for DM1 including (i) AMO Pharma evaluating tideglusib, a GSK3-ß inhibitor, (ii) Arrowhead Pharmaceuticals evaluating an RNA interference (RNAi) conjugate,conjugate (licensed to Sarepta Therapeutics), (iii) Arthex Biotech evaluating anti-miRNA oligonucleotides, (iv) Avidity Biosciences (recently acquired by Novartis) evaluating an antibody linked siRNA, (v) Dyne Therapeutics evaluating an antibody linked oligonucleotide, (vi) EditForce evaluating an RNA editing technology, (vii) an AAV-based RNA degrading gene therapy by Enzerna Biosciences, (viii) small molecules interacting with RNA under evaluation by Expansion Therapeutics, (ix) Harmony Biosciences evaluating a histamine 3 receptor for the treatment of excessive daytime sleepiness in DM1, (xviii) Juvena Therapeutics evaluating JUV-161, a stem cell-secreted protein, (xiix) Modalis Therapeutics evaluating MDL-202, a gene therapy candidate, (xiix) PepGen evaluating a peptide conjugated antisense oligonucleotide, (xiiixi) Sanofi evaluating an AAV-delivered miRNA, (xii) Transition Bio evaluating condensate therapeutics, and (xivxiii) Vertex Pharmaceuticals evaluating a peptide conjugated oligonucleotide (licensed from Entrada Therapeutics).

We are aware of a number of companies with active clinical-stage HD programs including (i) Alnylam Pharmaceuticals evaluating an RNAi therapeutic, (ii) Annexon Biosciences evaluating a monoclonal antibody, (iii) AskBio evaluating AAV delivered cholesterol 24-hydroxylase gene, (iv) Hoffmann-La Roche AG evaluating Tominersen, an antisense oligonucleotide,oligonucleotide candidate and a gene therapy candidate, (viv) Prilenia Therapeutics evaluating a sigma-1 receptor agonist, (viv) PTC Therapeutics evaluating a splicing modifier,modifier (licensed to Novartis), (vi) Sarepta Therapeutics evaluating an siRNA, (vii) Skyhawk Therapeutics evaluating a splicing modifier, (viii) uniQure evaluating an AAV deliveredAAV-delivered miRNA, (ix) Vaccinex evaluating a monoclonal antibody, (x) VICO Therapeutics evaluating an antisense oligonucleotide, and (xi) Wave Life Sciences evaluating an antisense oligonucleotide.

We will also compete more generally with other companies developing alternative scientific and technological approaches to modulate individual genes, including other companies working to develop nuclease-based gene editing technologies, such as Beam Therapeutics, CRISPR Therapeutics, Editas Medicine, Intellia Therapeutics, Precision BioSciences, Rocket Pharmaceuticals, Sangamo Biosciences and Verve Therapeutics.Therapeutics (a wholly owned subsidiary of Eli Lilly and Company).

We do not have any manufacturing facilities. We rely on third parties for the manufacture of our product candidates for nonclinical and clinical testing. We will continue to rely on such third parties for commercial product manufacture, if any of our product candidates are approved. We currently have limited manufacturing arrangements and expect that each of our product candidates will only be covered by single source suppliers for the foreseeable future. This reliance increases the risk that we will not have sufficient quantities of our product candidates or products, if approved, or such quantities at an acceptable cost or quality, which could delay, prevent or impair our development or commercialization efforts. For example, as previously announced in May 2023, an unanticipated issue related to the vial stopper used by our vendor for manufacturing the prior DT-216 product candidateDT-216P1 caused a short delay in product supply for the Phase 1 MAD clinical trial.trial of DT-216P1. In addition, we currently have only one supplier for one of the excipient components of DT-216P2. We may not be able to establish additional sources of supply for this excipient component of DT-216P2 or our other product candidates on a timely basis, or at all, or may be unable to do so on acceptable terms.

Certain Chinese biotechnology companies, CROs and contract development and manufacturing organizations may become subject to trade restrictions, sanctions, other regulatory requirements, or proposed legislation by the U.S. government, which could potentially impact services available for our research and development or our ability to secure the materials we need for our product candidates. ForOn example,December 18, 2025, the HouseNational ofDefense RepresentativesAuthorization ofAct thefor priorFiscal CongressYear 2026 (the 118th CongressNDAA) passedwas signed into law, which includes the BIOSECURE Act,Act whichwhich, proposedin prohibitingits current form, would prohibit the U.S. government from procuring biotechnology equipment or services from “biotechnology companies of concern,” and would prohibit U.S. government contracts, grants,loans and loansgrants to entitiesany entity that useuses biotechnology equipment andor services from certaina nameddesignated “biotechnology company of concern.” “Biotechnology companies of concern” include companies identified on the U.S. Department of Defense’s “Chinese biotechmilitary companies,companies operating in the United States” list (the 1260H List) and also authorizes the U.S. government to nameidentify additional Chineseentities for inclusion as “biotechnology companies of concern.” The BIOSECURE Act did not become law in the 118th Congress. It is unclear whether the current Congress (the 119th Congress) will introduceWith the BIOSECURE ActAct, we may be restricted in our ability to work with certain Chinese biotechnology manufacturing companies to the extent we would contract with, or similarotherwise legislationreceive infunding this congressional session and, if so, howfrom, the scope,U.S. prohibitions,government. In addition, any U.S. executive action, legislative action or designatedpotential sanctions with China could materially impact entities that work with Chinese biotechnology companiescompanies. U.S. executive agencies may designate entities and individuals on various governmental prohibited and restricted parties lists. Depending on the designation, potential consequences can range from a comprehensive prohibition on all transactions or dealings with designated parties, or a limited prohibition on certain types of concernactivities, maysuch differas fromexports and financing activities, with designated parties. Such disruption could have adverse effects on the versiondevelopment of theour BIOSECUREproduct Act passed by the House in the prior 118th Congress.candidates.

Our or a third-party’sthird party’s failure to execute on our manufacturing requirements, or to so execute on commercially reasonable terms and timelines in compliance with cGMP requirements, could adversely affect our business in a number of ways, including:

As product candidates progress through nonclinical to late-stage clinical trials to marketing approval and commercialization, it is common that various aspects of the development program, such as manufacturing methods, are altered along the way in an effort to optimize yield, manufacture batch size, change drug product dosage form, minimize costs and achieve consistent quality and results. Such changes carry the risk that they will not achieve these intended objectives. Any of these changes could cause our product candidates to perform differently and affect the results of clinical trials or other future clinical trials conducted with the altered materials. This could delay completion of clinical trials, require the conduct of bridging clinical trials or nonclinical studies or the repetition of one or more clinical trials, increase clinical trial costs, delay approval of our product candidates and jeopardize our ability to commercialize our product candidates and generate revenue. For instance, while DT-216 was generally well-tolerated and exhibited the ability to overcome the FXN transcription impairment that causes FA in the Phase 1 SAD clinical trial and the Phase 1 MAD clinical trial,trial of DT-216P1, thrombophlebitis at the injection site thrombophlebitis was observed in patients at lower dose levels in the Phase 1 MAD clinical trial.trial of DT-216P1 and data from the Phase 1 MAD clinical trial for DT-216P1 suggests more sustained exposure to DT-216 is likely needed to achieve a more durable increase in FXN expression. Instead of advancing the prior DT-216 product candidateDT-216P1 through to Phase 2 in the second half of 2023 as originally planned, due to the potential benefits of improved exposure and concern for potential worsening of thrombophlebitis at the injection site thrombophlebitis at higher doses with multiple administration, we decided to pursue development of a potentially improved formulation using a novel and proprietary excipient with DT-216P2 which has shown improved properties, including favorable injection site tolerability that we believe may better support the future clinical development and regulatory pathway for the drug substance, DT-216. WeIt withdrewis possible that our INDproduct forcandidates may require additional formulation or drug substance changes in the priorfuture DT-216to productsupport candidate in October 2023. We have initiated a Phase 1 SADcontinued clinical trialdevelopment. ofIn DT-216P2such inevent, normalour healthydevelopment volunteerstimelines in Australia to evaluate single doses using multiple routes of administration, specifically IV infusion and SC injection and infusion routes. Results from this Phase 1 SAD clinical trial will inform the design of a clinical trial in FA patients, anticipated to begin in mid-2025. We anticipate providing an update in 2026 on the effect of DT-216P2 on endogenous FXN levels following 12 weeks of dosing. However, there canmay be nomaterially assuranceadversely that we will be able to successfully develop DT-216P2 with improved injection site tolerability and the absence of other unacceptable side effects on the timeframe we expect, or at all, or that we will be able to achieve our anticipated timeline for resumed Phase 1 clinical development and data.impacted.

We expect to experience pricing pressures in connection with the sale of any of our product candidates due to the trend toward managed healthcare, the increasing influence of health maintenance organizations, and additional legislative changes. The downward pressure on healthcare costs in general, particularly prescription medicines, medical devices and surgical procedures and other treatments, has become very intense. As a result, increasingly high barriers are being erected to the successful commercialization of new products. For example, the U.S. Department of Health and Human Services (HHS) imposes rebates on many Medicare Part B and Medicare Part D products to penalize price increases that outpace inflation on an annual basis. In addition, HHS has been empowered to negotiate the price of certain single-source drugs that have been on the market for at least seven (7) years covered under Medicare as part of the Medicare Drug Price Negotiation Program. Each year up to twenty (20) products will be selected by HHS for the Medicare Drug Price Negotiation Program. Products subject to the Medicare Drug Price Negotiation Program are expected to experience a significant reduction in reimbursement from the Medicare program on a per unit basis. Further, the adoption and implementation of any future governmental cost containment or other health reform initiative may result in additional downward pressure on the price that we may receive for any approved product.

In preclinical studies for our lead program in FA, we have observed restoration of frataxin (FXN) levels in multiple cell types from FA patients and an in vivo murine model of FA using our FA GeneTAC® molecules. At doses that were observed to be well toleratedwell-tolerated in rodents and non-human primates (NHPs), FA GeneTAC® molecules achieved biodistribution to brain and heart, key organs affected by FA, at concentrations that exceeded those observed to restore FXN levels in FA patient cells. Further, and consistent with this favorable target-organ biodistribution, we observed increased endogenous FXN expression in the brain and heart in an animal model of FA after treatment with our FA GeneTAC® molecules. InPreviously, Februarywe 2022,reported theclinical Investigational New Drug Application (IND)data for our lead FA GeneTAC® small molecule, DT-216, formulated as the prior DT-216 product candidate, was cleared by the U.S. Food and Drug Administrationcandidate (FDADT-216P1) to commence Phase 1 clinical trials. In December 2022, we reported positive initial data from thea Phase 1 single-ascending dose (SAD) clinical trial in December 2022 and in August 2023, we reported data from thea Phase 1 multiple-ascending dose (MAD) clinical trial ofin theAugust prior DT-216 product candidate.2023. Both studies showed that DT-216 was generally well-tolerated and exhibited the ability to overcome the FXN transcription impairment that causes FA. Data from the Phase 1 MAD clinical trial for DT-216P1 suggests more sustained exposure to DT-216 is likely needed to achieve a more durable increase in FXN expression, and we observed five cases of injection site thrombophlebitis in the Phase 1 MAD clinical trial.expression. We then shifted focus to developing DT-216 with a potentially improved formulation to enable highermore sustained exposure andfor chronic administration forthe treatment of FA. These efforts resulted in a new product candidate, DT-216P2, which uses the same drug substance, DT-216. In nonclinical studies, we observed higher and more sustained DT-216 plasma levels after administration of DT-216P2 than was seen in studies with the prior DT-216 product candidate. Additionally, we observed favorable injection site tolerability following multiple intravenous (IV) administrations of DT-216P2. We have initiated a Phase 1 SAD clinical trial of DT-216P2 in normal healthy volunteers in Australia to evaluate single doses using multiple routes of administration, specifically IV infusion and subcutaneous (SC) injection and infusion routes. Results from this Phase 1 SAD clinical trial will inform the design of a clinical trial in FA patients, anticipated to begin in mid-2025. We anticipate providing an update in 2026 on the effect of DT-216P2 on endogenous FXN levels following 12 weeks of dosing.DT-216P1.

In December 2022, we nominated our second GeneTAC® small molecule, DT-168, an eye drop for the treatment of FECD. When tested in vitro in FECD patient-derived corneal endothelial cells, our FECD GeneTAC® molecules led to robust reductions in the pathogenic nuclear RNA foci and corrected key mis-spliced transcripts to levels observed in control corneal endothelial cells from unaffected donors. DT-168 was well-tolerated and distribution of DT-168 was observed in and through the cornea in animal models after administration via eye drop. In addition, DT-168 has been evaluated in chronic toxicity studies of up to nine months in duration. We believe these preclinical data support the potential of our novel GeneTAC® small molecules to correct the most common underlying genetic cause of FECD. We have completed dosing in a Phase 1 clinical trial in normal healthy volunteers to evaluate the safety of DT-168 and plan to provide results in the first half of 2025. In addition, DT-168 has been evaluated in chronic toxicity studies of up to nine months in duration. We are currently conducting an observational study in FECD to confirm disease characteristics and evaluate deterioration in the context of running a trial and to identify characteristics of FECD patients at risk of more rapid disease progression. We have achieved our enrollment goal for the observational study by recruiting and completing baseline assessments on approximately 250 FECD patients. Based on the baseline characteristics data, we have chosen approximately 100 patients for future follow-up visits. This will inform our clinical development efforts and we believe it could potentially increase the probability of DT-168 programmatic success.

We have funded our operations primarily through the sale of our common stock, convertible preferred stock, grant revenue and the issuance of convertible notes and debt. In March 2021, we completed our initial public offering in which we sold 13,800,000 shares of our common stock at $20.00 per share and received net proceeds, after underwriting discount and offering costs, of $254.3 million. InDuring Januarythe 2021,year ended December 31, 2025, we issuedsold 19,083,979an aggregate of 3,250,510 shares of Seriesour B convertible preferredcommon stock atpursuant $6.55to perour share“at-the-market” sales agreement (ATM Program) for aggregate net proceeds of approximately $124.7$24.8 million. Our cash, cash equivalents and investment securities balance as of December 31, 2024,2025, was $245.5$219.8 million.

The following table summarizes our research and development expenses by program and by direct and indirect costs for the year ended December 31, 20242025 and 20232024 (in thousands):

General and Administrative Expenses. The decreaseincrease in general and administrative expenses in 20242025 compared to 20232024 was primarily due to lowera headcount,$1.8 resultingmillion increase in aemployee $2.3compensation, including $1.5 million decrease in personnel-relatedstock-based compensation expense, a $0.4 million one-time charge to deferred financing costs inclusiveand of stock-based compensation, a $0.6$0.1 million decrease in professional services and a $0.2 million decrease in other expenses.expenses incurred during the year ended December 31, 2025 as compared to the same period in 2024.

We have incurred net losses and negative cash flows from operations since our inception and anticipate we will continue to incur net losses for the foreseeable future. Since our inception, we have funded our operations primarily through the sale of our common stock, convertible preferred stock, grant income and the issuance of convertible notes and notes payable. As of December 31, 2024,2025, we had $245.5$219.8 million of combined cash andcash, cash equivalents and investment securities, a decrease of $36.3$25.6 million from the $281.8$245.5 million of cash andcash, cash equivalents and investment securities at December 31, 2023.2024. The following table summarizes our cash flow activities (in thousands):

Operating Activities. The decreaseincrease in our net cash used in operating activities was primarily due to the $17.3$20.1 million decreaseincrease in net loss, partially offset by an increase in non-cash expenses and net working capital for the year ended December 31, 20242025 compared to the same period of the prior year. The lower net loss incurred during the 2024 period was primarily due to decreased expenses related to our FA program and lower personnel-related costs.

Financing Activities. Net cash provided by financing activities for each of the years ended December 31, 20242025 and 20232024 was comprised of proceeds received from the issuance of common stock through our employee stock purchase plan and from employee stock option exercises. During the year ended December 31, 2025, we sold an aggregate of 3,250,510 shares of our common stock pursuant to the ATM Program for aggregate net proceeds of approximately $24.8 million.

In AprilMay 2022,2025, we filed a shelf registration statement on Form S-3 (2022the 2025 Shelf Registration Statement), which became effective in May 2022.. The 20222025 Shelf Registration Statement permits: (i) the offering, issuance and sale by us of up to a maximum aggregate offering price of $300.0 million of common stock, preferred stock, debt securities and warrants in one or more offerings and in any combination; and (ii) the offering, issuance and sale by us of up to a maximum aggregate offering price of $100.0 million of our common stock that may be issued and sold under anour "at-the-market” sales agreement (ATM Program).Program. The $100.0 million of common stock that may be issued and sold under the ATM Program is included in the $300.0 million of securities that may be issued and sold under the 20222025 Shelf Registration Statement. AsDuring ofthe year ended December 31, 2024,2025, the Company has notwe sold anyan aggregate of 3,250,510 shares of itsour common stock underpursuant to the ATM Program.Program for aggregate net proceeds of approximately $24.8 million.

Based on our current operating plan, we believe that our existing cash, cash equivalents and investmentsinvestment securities will be sufficient to fund our planned operating expenses and capital expenditure requirements for more than the next 12 months following the date of this Annual Report.

Until such time, if ever, as we can generate substantial revenues from product sales to support our cost structure, we expect to finance our cash needs through public or private equity offerings, debt financings, or other capital sources which may include strategic collaborations, licensing arrangements or other arrangements with third parties. To the extent that we raise additional capital through the sale of equity or convertible debt securities, the ownership interest of our stockholders will be or could be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect the rights of our common stockholders. Equity and debt financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends. If we raise funds through strategic collaborations, or other similar arrangements with third parties, we may have to relinquish valuable rights to our technologies, future revenue streams, research programs or product candidates or grant licenses on terms that may not be favorable to us and/or may reduce the value of our common stock. If we are unable to raise additional funds through equity or debt financings when needed, we may be required to delay, limit, reduce or terminate our drug development or future commercialization efforts. Our ability to raise additional funds may be adversely impacted by potential worsening global economic conditions and disruptions to and volatility in the credit and financial markets in the United States and worldwide as a result of macroeconomic factors, including geopolitical conflicts (such as the geopolitical tensions between the U.S. and China, the ongoing Russia/Ukraine conflict and the Israel-Hamas war),conflicts, inflation, tariffs, other fiscal and trade policy changes, bank failures, global supply chain and labor shortage challenges, and the effects of a health epidemic or pandemic. Because of the numerous risks and uncertainties associated with product development, we cannot predict the timing or amount of increased expenses and cannot assure you that we will ever be profitable or generate positive cash flow from operating activities.

For the year ended December 31, 2025, no payments were made pursuant to the License Agreement. In 2022, pursuant to the License Agreement, we paid $0.1 million to WARF upon the acceptance of an IND in the U.S.United andStates. We will be required to make further aggregate milestone payments of up to $17.5 million upon achievement of certain other regulatory and commercial milestones. We may also be required to pay royalties based on annual net product sales in the low single digits on our or our sublicensees’ net product sales on a country-by-country and product-by-product basis, and are subject to a minimum royalty of $100,000$0.1 million per calendar year upon first commercial product sale. Further, we may be required to pay sublicense fees in the mid-single digits percentage for fees, royalties or other payments earned from the granting of sublicenses to the WARF patents and know-how. The Company will recognize these milestone payments and royalties when paid or payable. There were no additional payments or royalties recorded through December 31, 2024.2025.

During the year ended December 31, 2025, we recorded $0.1 million to research and development expenses related to regulatory milestones, which is included in accrued expenses and other current liabilities as of December 31, 2025. There were no additional payments or royalties recorded through December 31, 2025. We may be obligated to make aggregate regulatory milestone payments of up to $0.8 million for each product incorporating licensed patent rights and pay a royalty on worldwide net sales on a product-by-product basis. The Company will recognize these milestone payments and royalties when paid or payable. There were no additional payments or royalties recorded through December 31, 2024.

We are an emerging growth company, as defined in the Jumpstart Our Business Startups Act, as amended (JOBS Act), and we maywill remain an emerging growth company until as late as December 31, 2026 (the fiscal year-end following the fifth anniversary of the completion of our initial public offering). For so long as we remain an emerging growth company, we are permitted and intend to rely on certain exemptions from various public company reporting requirements, including not being required to have our internal control over financial reporting audited by our independent registered public accounting firm pursuant to Section 404 of the Sarbanes-Oxley Act, reduced disclosure obligations regarding executive compensation in our periodic reports and proxy statements, and exemptions from the requirements of holding a nonbinding advisory vote on executive compensation and any golden parachute payments not previously approved.

We are a clinical-stage biopharmaceutical company with a limited operating history that may make it difficult to evaluate the success of our business to date and to assess our future viability. Our operations to date have been limited to business planning, organizing and staffing our company, raising capital, developing and optimizing our technology platform, identifying potential product candidates, undertaking research and nonclinical studies for our lead program in FA and our other development programs, early clinical development for our FA, FECD and DM1 programs, establishing and enhancing our intellectual property portfolio, and providing general and administrative support for these operations. As a result, none of our product candidates have been approved for commercial sale. We have never generated any revenue from product sales and have incurred net losses each year since we commenced operations, including a net loss of $17.6$37.8 million and $69.8 million for the threesix months ended MarchJune 31,30, 2026 and the year ended December 31, 2025, respectively. We expect that it will be several years, if ever, before we have a product candidate ready for regulatory approval and commercialization. We expect to incur increasing levels of operating losses over the next several years and for the foreseeable future as we advance our product candidates through clinical development. Our prior losses, combined with expected future losses, have had and will continue to have an adverse effect on our stockholders’ equity and working capital.

As of MarchJune 31,30, 2026, we had $222.8$207.4 million in cash, cash equivalents and investment securities. Based upon our current operating plan, we estimate that our existing cash, cash equivalents and investment securities will be sufficient to fund our operating expenses and capital expenditure requirements for more than the next 12 months. However, we believe that our existing cash, cash equivalents and investment securities will not be sufficient to fund any of our product candidates through regulatory approval, and we will need to raise substantial additional capital to complete the development and commercialization of our product candidates.

orour costs associated with expanding our facilities or building out additional laboratory space; and the cost associated with commercialization activities for any of our product candidates, if approved.

We are early in our development efforts. Our lead FA GeneTAC® small molecule, DT-216, formulated as the prior DT-216 product candidate (DT-216P1), entered into a Phase 1 SAD clinical trial in March 2022, the first clinical trial for one of our product candidates, and we completed the Phase 1 MAD clinical trial of DT-216P1 in August 2023. We withdrew our IND for DT-216P1 in October 2023, and we are conducting our RESTORE-FA Phase 1/2 MAD clinical trial of DT-216P2, which uses the same drug substance, DT-216, to evaluateassess safety, pharmacokinetics, biomarkerpharmacodynamics, endpoints assessingincluding changes in endogenous FXNFXN, andas exploratorywell as clinical endpoints. Furthermore, we are conducting a Phase 2 biomarker trial of DT-168, our FECD GeneTAC® product candidate, to evaluate safety, tolerability, and corneal endothelium biomarkers in FECD patients withwho FECD.are scheduled for corneal transplant surgery. We have initiated patient dosing in a Phase 1 MAD trial of DT-818, our DM1 GeneTAC® product candidate,candidate. The study is an open-label study designed to evaluate the safety, tolerability, pharmacokinetics and pharmacodynamic effects of multiple-ascending doses of DT-818 in adults with normal healthy volunteers and plan to begin dosing DM1 patients in the first half of 2026. The study, with results anticipated in 2027, is expected to assess safety and correction of mis-splicing.2027. We have limited infrastructure, experience conducting clinical trials as a company and regulatory interactions, and cannot be certain that our clinical trials will be completed on time, if at all, that our planned development programs would be acceptable to the FDA or other comparable foreign regulatory authorities, or that, if approval is obtained, such product candidates can be successfully commercialized.

While we have conducted nonclinical studies of DT-216P1 for the treatment of patients with FA, released initial clinical data from our Phase 1 SAD clinical trial in December 2022 and released initial results from the Phase 1 MAD clinical trial of DT-216P1 in August 2023 with results showing that DT-216 was generally well-tolerated and exhibited the ability to overcome the FXN transcription impairment that causes FA, data from the Phase 1 MAD clinical trial for DT-216P1 suggests more sustained exposure to DT-216 is likely needed to achieve a more durable increase in FXN expression and self-limited thrombophlebitis at the injection site was observed in five patients across all three dose levels (100 mg, 200 mg and 300 mg) in the Phase 1 MAD clinical trial of DT-216P1, whereas thrombophlebitis at the injection site was only observed at higher doses (the 400 mg and 600 mg cohorts) in the Phase 1 SAD clinical trial of DT-216P1. Nonclinical studies showed that the thrombophlebitis at the injection site was attributable to the formulation excipients in the prior DT-216P1 product candidate formulation, and that improving the formulation composition could improve exposure, enable higher doses and chronic administration. We have since shown that a potentially improved formulation using a novel and proprietary excipient with DT-216P2 had improved properties, including favorable injection site tolerability, following multiple intravenous administrations and enabled dosing to increase tissue exposure. Given the potential benefits of improved exposure, thrombophlebitis observed in the Phase 1 MAD clinical trial of DT-216P1 and concern for potential worsening of thrombophlebitis at the injection site at higher doses with multiple administration, and the initial results from animal studies using a novel and proprietary excipient in DT-216P2, instead of advancing DT-216P1 through to Phase 2 in the second half of 2023 as originally planned, we decided to pursue development of DT-216P2 to better support the future clinical development and regulatory pathway for the drug substance DT-216. We are conducting our RESTORE-FA Phase 1/2 MAD clinical trial of DT-216P2 in patients with FA. The RESTORE-FA trial is a multiplePhase ascending1/2 doseclinical studytrial ofevaluating DT-216P2 administeredin throughpatients eitherwith IVFA, or SC over four- or 12-week treatment periodsdesigned to evaluateassess safety, pharmacokinetics, biomarkerpharmacodynamics, endpoints assessingincluding changes in endogenous FXNFXN, andas exploratorywell as clinical endpoints. WeIn anticipateMay providing2026, anwe updateannounced biomarker and clinical data from the RESTORE-FAfour-week trialIV on the effect of DT-216P2 on endogenous frataxin levelscohorts in the secondongoing halfRESTORE-FA trial which showed dose-dependent increases in FXN levels and dose-dependent improvements across multiple clinical measures, including mFARS, upright stability score and patient-reported fatigue after four weeks of 2026.IV treatment. We believe the thrombophlebitis at the injection site seen with DT-216P1 is no longer an issue limiting continued development of DT-216. However, there can be no assurance that we will be able to successfully develop DT-216P2 with improved properties, including favorable injection site tolerability and the absence of other unacceptable side effects on the timeframe we expect, or at all, or that we will be able to achieve our anticipated clinical development and data timelines for the RESTORE-FA trial. In addition, in June 2025, we received a clinical hold notice from the FDA regarding our IND for DT-216P2. In December 2025, the clinical hold was lifted and we received clearance from the FDA to initiate clinical studies for DT-216P2.

If we encounter difficulties or delays enrolling patients in our clinical trials, our clinical development activities could be delayed or otherwise adversely affected.*

In addition, our clinical trials may compete with other clinical trials for product candidates that are in the same therapeutic areas as our product candidates, and this competition may reduce the number and types of patients available to us, because some patients who might have opted to enroll in our trials may instead opt to enroll in a trial being conducted by one of our competitors. We may also experience enrollment challenges if patients that would otherwise enroll in our trial choose not to do so, or are not eligible to do so, as a result of treatment with another drug. For example, the FDA approved omaveloxolone for the treatment of FA in adults and adolescents aged 16 years and older in February 2023, and omaveloxolone was commercially launched in June 2023. The availability of omaveloxolone may impact future enrollment of our planned clinical trials. FA patients receiving omaveloxolone may be ineligible to enroll in a clinical trial for DT-216P2 or may choose not to do so due to the availability of an approved product. Furthermore, patients enrolled in our clinical trials may receive omaveloxolone and we cannot predict the impact of potential drug interactions on trial results. Likewise, patient enrollment for our plannedongoing Phase 1 MAD study of DT-818 may be adversely impacted by competition from clinical trials for other DM1 treatments. Delays in patient enrollment may result in increased costs or may affect the timing or outcome of our clinical trials, which could prevent completion of these trials and adversely affect our ability to advance the development of our product candidates.

Early, interim, topline and preliminary data from our nonclinical studies or clinical trials that we announce or publish from time to time may change as more patient data become available and are subject to audit and verification procedures that could result in material changes in the final data.*

For example, a Phase 1 SAD clinical trial of DT-216P2 in normal healthy volunteers to evaluate single doses using multiple routes of administration, specifically IV infusion and SC injection and infusion routes, has shown that DT-216P2 has been generally well-tolerated. Human plasma pharmacokinetics (PK) profiles of DT-216P2 were consistent with NHP data following both IV and SC single-dose administration and human PK data demonstrated that DT-216P2 exhibited improved exposure and PK parameters compared to DT-216P1, including higher AUC and sustained plasma levels at comparable doses. In May 2026, we announced biomarker and clinical data from the four-week IV cohorts in the ongoing RESTORE-FA trial evaluating DT-216P2 in FA patients which showed dose-dependent increases in FXN levels and dose-dependent improvements across multiple clinical measures, including mFARS, upright stability score and patient-reported fatigue after four weeks of IV treatment. It is possible that our exposure, PKPK, pharmacodynamics, clinical endpoints and other observations will materially change as additional data becomes available, including from the ongoing RESTORE-FA Phase 1/2 MAD clinical trial.

International trade policies, including tariffs, sanctions and trade barriersbarriers, may adversely affect our business, financial condition, results of operations and prospects.

We are aware of a number of companies with active clinical-stage HD programs including (i) Alnylam Pharmaceuticals evaluating an RNAi therapeutic, (ii) Annexon Biosciences evaluating a monoclonal antibody, (iii) Hoffmann-La Roche AG evaluating an antisense oligonucleotide candidate and aAAV gene therapy candidate, (iv) Prilenia Therapeutics evaluating a sigma-1 receptor agonist, (v) PTC Therapeutics evaluating a splicing modifier (licensed to Novartis), (vi) Sarepta Therapeutics evaluating an siRNA, (vii) Skyhawk Therapeutics evaluating a splicing modifier, (viii) uniQure evaluating an AAV-delivered miRNA, (ix) Vaccinex evaluating a monoclonal antibody, (x) VICO Therapeutics evaluating an antisense oligonucleotide, and (xi) Wave Life Sciences evaluating an antisense oligonucleotide.

We will also compete more generally with other companies developing alternative scientific and technological approaches to modulate individual genes, including other companies working to develop nuclease-based gene editing technologies, such as Beam Therapeutics, CRISPR Therapeutics, Editas Medicine, Intellia Therapeutics, Precision BioSciences, Rocket Pharmaceuticals, Sangamo BiosciencesPharmaceuticals and Verve Therapeutics (a wholly owned subsidiary of Eli Lilly and Company).

We contract with third parties for the manufacturing and supply of our product candidates for use in nonclinical testing and clinical trials, which supply may become limited or interrupted or may not be of satisfactory quality and quantity.*

In the event that any of our manufacturers fails to comply with such requirements or to perform its obligations to us in relation to quality, timing or otherwise, or if our supply of components or other materials becomes limited or interrupted for other reasons, including due to global supply chain challenges, geopolitical events impacting trade with global partners, labor shortages, or a health epidemic or pandemic, we may be forced to manufacture the materials ourselves, for which we currently do not have the capabilities or resources, or enter into an agreement with another third- party,third-party, which we may not be able to do on commercially reasonable terms, if at all. In particular, any replacement of our manufacturers could require significant effort and expertise because there may be a limited number of qualified replacements. In some cases, including for one of the excipient components of DT-216P2, the technical skills or technology required to manufacture our product candidates may be unique or proprietary to the original manufacturer and we may have difficulty transferring such skills or technology to another third-party and a feasible alternative may not exist. These factors would increase our reliance on such manufacturer or require us to obtain a license from such manufacturer in order to have another third-party manufacture our product candidates. If we are required to or voluntarily change manufacturers for any reason, we will be required to verify that the new manufacturer maintains facilities and procedures that comply with quality standards and with all applicable regulations and guidelines and that the product produced is equivalent to that produced in a prior facility. The delays associated with the verification of a new manufacturer and equivalent product could negatively affect our ability to develop product candidates in a timely manner or within budget.

Certain Chinese biotechnology companies, CROs and contract development and manufacturing organizations may become subject to trade restrictions, sanctions, other regulatory requirements, or proposed legislation by the U.S. government, which could potentially impact services available for our research and development or our ability to secure the materials we need for our product candidates. On December 18, 2025, the National Defense Authorization Act for Fiscal Year 2026 (the NDAA) was signed into law, which includes the BIOSECURE Act which,which in its current form, would prohibitprohibits the U.S. government from procuring biotechnology equipment or services from “biotechnology companies of concern,” and would prohibit U.S. government contracts, loans and grants to any entity that uses biotechnology equipment or services from a designated “biotechnology company of concern.” “Biotechnology companies of concern” will include (i) certain companies identified on the U.S. Department of Defense’s “Chinese military companies operating in the United States” list (the 1260H List), and(ii) alsocompanies authorizesthat the U.S. governmentGovernment designates as a “biotechnology company of concern” pursuant to identifycertain additionalcriteria, and (iii) certain subsidiaries or parent or successor entities forof inclusionthe asforegoing. The Office of Management and Budget is to issue a list of “biotechnology companies of concern.concern” by mid-December 2026. There is a “safe harbor” provision providing that the restrictions do not apply to equipment or services that were formerly but are no longer provided by a “biotechnology company of concern,” as well as a “grandfathering” provision providing that the prohibitions shall not apply for a five-year period to biotechnology equipment or services produced or provided under a contract or agreement entered into before the applicable effective date. With the BIOSECURE Act, we may be restricted in our ability to work with certain Chinese biotechnology manufacturing companies to the extent we would contract with, or otherwise receive funding from, the U.S. government. In addition, any U.S. executive action, legislative action or potential sanctions with China could materially impact entities that work with Chinese biotechnology companies. U.S. executive agencies may designate entities and individuals on various governmental prohibited and restricted parties lists. Depending on the designation, potential consequences can range from a comprehensive prohibition on all transactions or dealings with designated parties, or a limited prohibition on certain types of activities, such as exports and financing activities, with designated parties. Such disruption could have adverse effects on the development of our product candidates.

As of MarchJune 31,30, 2026, we had 5455 employees. In addition, we also utilize specialized contract research organizations for additional research and development personnel. Together with our employees, our team comprised approximately 120121 full-time equivalents as of MarchJune 31,30, 2026. As we advance our research and development programs, we may be required to further increase the number of our employees and the scope of our operations, particularly in the areas of clinical development, discovery biology, chemistry, product development, general and administrative matters relating to being a public company, regulatory affairs and, if any of our product candidates receives marketing approval, sales, marketing and distribution. To manage any future growth, we must:

Numerous U.S. states have enacted comprehensive privacy laws that impose certain obligations on covered businesses, including providing specific disclosures in privacy notices and affording residents with certain rights concerning their personal data. As applicable, such rights may include the right to access, correct, or delete certain personal data, and to opt-out of certain data processing activities, such as targeted advertising, profiling, and automated decision-making. The exercise of these rights may impact our business and ability to provide our products and services to the extent we become subject to these laws in the future. Certain states also impose stricter requirements for processing certain personal data, including sensitive information, such as conducting data privacy impact assessments. These state laws allow for statutory fines for noncompliance. For example, the California Consumer Privacy Act of 2018 (CCPA) applies to personal data of consumers, business representatives, employees and other individuals who are California residents, and requires businesses subject to the CCPA to provide specific disclosures in privacy notices and honor requests of such individuals to exercise certain privacy rights. The CCPA provides for fines and allows private litigants affected by certain data breaches to recover significant statutory damages. While these states, like the CCPA, also exempt some data processed in the context of clinical trials, these developments further complicate compliance efforts, and increase legal risk and compliance costs for us and the third parties upon whom we rely, should we become subject to them in the future. Similar laws are being considered in several other states, as well as at the federal and local levels, and we expect more states to pass similar laws in the future.

Disruptions to the operations of the FDA, the SEC, other U.S. governmental agencies or comparable foreign regulatory authorities caused by funding shortages, leadership changes, staffing cuts or other staffing shortages, along with uncertainty regarding the potential for new initiatives, laws, regulations, policies and guidance affecting our product candidates or other aspects of our business, could materially and adversely affect our business.*

Over the last several years, the U.S. government has shut down several times and certain regulatory agencies, such as the FDA and the SEC, have had to furlough critical FDA, SEC and other government employees and stop critical activities. In addition, there have recently been terminations of large numbers of federal employees at various federal agencies, including the FDA. Changes and cuts in FDA staffing could result in delays in the FDA’s responsiveness or in its ability to review IND submissions or applications, issue regulations or guidance, or implement or enforce regulatory requirements in a timely fashion, or at all. AIf a prolonged government shutdown occurs and/or employee terminations or resignations continue, it could significantly impact the ability of the FDA or other federal agencies to timely review and process our regulatory submissions, which could have a material adverse effect on our business. Further, future government shutdowns and/or employee terminations or resignations at the SEC could impact our ability to access the public markets and obtain necessary capital in order to properly capitalize and continue our operations.

Changes in patent law in the United States and other jurisdictions could diminish the value of patents in general, thereby impairing our ability to protect our product candidates.*

In addition, the patent positions of companies in the development and commercialization of pharmaceuticals are particularly uncertain. The U.S. Supreme Court has ruled on several patent cases in recent years, either narrowing the scope of patent protection available in certain circumstances or weakening the rights of patent owners in certain situations. We cannot predict how decisions by the federal courts, the U.S. Congress or the USPTO may impact the value of our patent rights. For example, the Supreme Court of the United States held in Amgen v. Sanofi (2023) that a functionally claimed genus was invalid for failing to comply with the enablement requirement of the Patent Act. In addition, the Federal circuit recently issued a decision, In re Cellect, LLC (2023) involving the interaction of patent term adjustment (PTA), terminal disclaimers, and obvious-type double patenting which may affect the patent term of any issued patents that rely on any PTA. Depending on future actions by the U.S. Congress, the U.S. courts, the USPTO and the relevant law-making bodies in other countries, the laws and regulations governing patents could change in unpredictable ways that would weaken our ability to obtain new patents or to enforce our existing patents and patents that we might obtain in the future. In the 2013 case Assoc. for Molecular Pathology v. Myriad Genetics, Inc., for instance, the U.S. Supreme Court held that certain claims to DNA molecules are not patentable. While we do not believe that any of the patents owned or licensed by us will be found invalid based on this decision, we cannot predict how future decisions by the courts, the U.S. Congress or the USPTO may impact the value of our patents. For example, the Inflation Reduction Act (IRA) passed by Congress authorizes the Secretary of the Department of HHS to negotiate prices directly with participating manufacturers for selected medicines covered by Medicare even if these medicines are protected by an existing patent. For small molecule medicines, the process begins seven years after initial approval by the FDA. Under recent legislative updates via the One Big Beautiful Bill (OBBB) Act, medicines that maintain one or more FDA orphan designations for rare diseases are exempt from this negotiation process, provided they are not approved for a non-orphan condition. Furthermore, if an exempt orphan medicine is subsequently approved for a broader, non-rare market indication, the 7-year negotiation countdown does not begin until the date of that non-orphan approval. While we do not believe that the IRAIRA, these expanded orphan drug exemptions, or itstheir combined effects will impact our ability to obtain patents in the near future, we cannot be certain whether it will affect our patent strategy in the long run. Additionally, in July 2025, the FDA announced its intent to increase transparency by publicly releasing portions of Complete Response Letters (CRLs) issued to drug and biologic sponsors. While the FDA has stated that confidential information will be protected, it remains unclear how such disclosures will be implemented. Because CRLs often contain specific observations about study design, clinical endpoints, chemistry, manufacturing, and controls (CMC) data, or other proprietary information, any public release could unintentionally disclose information that competitors may use to infer proprietary aspects of our product candidates or platform technologies. This could compromise the confidentiality of our trade secrets and know-how or facilitate third-party efforts to design around or challenge the validity, enforceability, or scope of our patents, or accelerate the development of generics or biosimilars. If we are required to modify or limit the information shared with the FDA to mitigate such risks, it could increase costs, slow our regulatory interactions, or delay product approval timelines.

Applicable data privacy and security obligations as well as public company disclosure obligations may require us, or we may choose, to notify relevant stakeholders, including affected individuals, regulators and investors, of certain security incidents or to take other actions, such as providing credit monitoring and identity protection services. Such disclosures and related actions can be costly, and the disclosures or the failure to comply with applicable requirements could lead to adverse impacts. If we (or a third party with whom we work) experience a security incident or are perceived to have experienced a security incident, which has occurred in the past, we may experience adverse consequences. These consequences may include the following: government enforcement actions (for example, investigations, fines, penalties, audits, and inspections); additional reporting requirements and/or oversight; restrictions on processing data (including personal data); litigation (including class claims); indemnification obligations; negative publicity; reputational harm; monetary fund diversions; interruptions in our operations (including availability of data); financial loss; and other similar harms. Security incidents and attendant consequences may impact our ability to conduct clinical trials or bring any approved products to market, and negatively impact our ability to grow and operate our business. Whether a cybersecurity incident is reportable to our investors may not be straightforward, may take considerable time to determine, and may be subject to change as the investigation of the incident progresses, including changes that may significantly alter any initial disclosure that we provide. Moreover, experiencing a material cybersecurity incident and any mandatory disclosures could lead to negative publicity, loss of investor or partner confidence in the effectiveness of our cybersecurity measures, diversion of management’s attention, governmental investigations, lawsuits, and the expenditure of significant capital and other resources.

We are conducting our RESTORE-FA (Reactivating Expression Suppressed Through Overcoming Repeat Expansion for FA) Phase 1/2 MAD clinical trial of DT-216P2 in patients with FA. The RESTORE-FA trial is a multiplePhase ascending1/2 doseclinical studytrial ofevaluating DT-216P2 administeredin throughpatients eitherwith IVFA, or SC over four- or 12-week treatment periodsdesigned to evaluateassess safety, pharmacokinetics, biomarkerpharmacodynamics, endpoints assessingincluding changes in endogenous FXNFXN, andas exploratorywell as clinical endpoints. WeIn anticipateMay providing2026, anwe updateannounced positive biomarker and clinical data from the RESTORE-FAfour-week trialIV on the effect of DT-216P2 on endogenous frataxin levelscohorts in the secondongoing halfRESTORE-FA trial which showed dose-dependent increases in FXN levels and dose-dependent improvements across multiple clinical measures, including the modified Friedreich’s Ataxia Rating Scale (mFARS), upright stability score (USS) and patient-reported fatigue after four weeks of 2026.IV treatment.

In May 2025, we reported results from a completed Phase 1, double-masked, placebo-controlled, randomized, SAD/MAD clinical trial evaluating the safety, tolerability and systemic PK of DT-168 ophthalmic solution in normal healthy volunteers. DT-168 eye drops were well-tolerated in all participants with a maximum dose of two 0.5% drops twice-daily for seven days. There were no serious adverse events, no ocular adverse events (AEs) and no treatment discontinuations due to AEs in the trial. All observed AEs were deemed not related to DT-168 by the trial investigator. In parallel with the Phase 1 trial, we conducted reference range studies which showed consistently different splicing in the corneal endothelium between unaffected eye donors and surgical samples from mutant TCF4 FECD patients, supporting the potential for corneal endothelium biomarkers as a clinical proof-of-concept measure of drug activity. We are conducting a Phase 2 biomarker trial of DT-168 to evaluate safety, tolerability, and corneal endothelium biomarkers in FECD patients withwho FECD.are Wescheduled anticipatefor reportingcorneal datatransplant fromsurgery. theData Phaseis 2now biomarkerexpected trialin 2027 due to a delay in the secondanticipated halfsupply of 2026.DT-168 blow-fill-seal eye droppers.

In the fourth quarter of 2025, we announced DT-818 as our GeneTAC® small molecule development candidate for the treatment of DM1. In preclinical studies, DT-818 has demonstrated a potential best-in-disease profile for DM1, including a greater than 90% reduction in toxic RNA foci in DM1 patient cells, corresponding splicing correction and selective targeting of mutant DMPK. In an actin repeat mouse model of DM1 (HSALR mouse model), DT-818 treatment resulted in improved myotonia and foci reduction. In tissue distribution studies in NHPs, DT-818 levels were observed to be at expected pharmacologic levels in key target tissues at well-tolerated doses. In the fourthfirst quarterhalf of 2025,2026, we obtained regulatory clearance to initiate clinical development of DT-818 and plan to begininitiated dosing DM1 patients in a Phase 1 MAD trial inof DT-818. The Phase 1 trial is an open-label study designed to evaluate the firstsafety, halftolerability, pharmacokinetics and pharmacodynamic effects of 2026.multiple Theascending study,doses of DT-818 in adults with resultsDM1. anticipatedWe anticipate reporting data from this study in 2027, is expected to assess safety and correction of mis-splicing.2027.

To date, we have incurred net losses and negative cash flows from operations since our inception and as of MarchJune 31,30, 2026 had an accumulated deficit of $314.6$334.8 million. Our cash, cash equivalents and investment securities balance as of MarchJune 31,30, 2026 was $222.8$207.4 million. Our net losses have resulted primarily from costs incurred in connection with organizing and staffing our company, business planning, raising capital, developing and optimizing our technology platform, identifying potential product candidates, undertaking research and nonclinical studies, clinical development activities, engaging in manufacturing for our development programs, and providing general and administrative support for these operations. We do not have any products approved for sale and have not generated any revenue from product sales.

Comparison of the Three Months Ended MarchJune 31,30, 2026 and 2025

The following table summarizes our operating expenses for the three months ended MarchJune 31,30, 2026 and 2025 (in thousands):

Research and Development Expenses. The decreaseincrease in research and development expenses compared to the same period of the prior year was primarily due to aan reductionincrease in expensesFA associatedclinical with our FAactivities and FECDhigher programs.indirect expenses.

Other direct expenses associated with our early-stage programs, thatwhich are not allocated on a program-by-program basis, decreased due to the movement of DM1 expenses to a separate program subcategory because of its shift to clinical development. The increase in indirect expenses compared to the same period of the prior year was primarily due to employee related expenses including compensation, stock-based compensation and other support for our ongoing development programs.

The following table summarizes our research and development expenses by program,program and other direct and indirect costs for the three months ended MarchJune 31,30, 2026 and 2025 (in thousands):

General and Administrative Expenses. The increasedecrease in general and administrative expenses was primarily due to a $0.2 million increasedecrease in stock-based compensation expenses and a $0.1 million increase in other expenses incurred during the three months ended MarchJune 31,30, 2026 as compared to the same period in 2025.

As of MarchJune 31,30, 2026, we had $222.8$207.4 million of combined cash, cash equivalents and investment securities, ana increasedecrease of $3.0$12.4 million from the $219.8 million of cash, cash equivalents and investment securities at December 31, 2025. Further detail of the change in our cash and cash equivalents for the threesix months ended MarchJune 31,30, 2026 and 2025 is summarized below (in thousands):

Operating Activities. The decreaseincrease in our net cash used in operating activities was primarily due to anthe increase in non-cash expenses partially offset by a $0.1$1.0 million decreaseincrease in net loss for the threesix months ended MarchJune 31,30, 2026 compared to the threesix months ended MarchJune 31,30, 2025.

Investing Activities. The decrease in net cash provided by investing activities was primarily due to a net decrease in cash provided from the maturities and purchases of our investment securities during the threesix months ended MarchJune 31,30, 2026 compared to the threesix months ended MarchJune 31,30, 2025. We have classified our investment securities as available-for-sale and all investments are made in accordance with our investment policy.

Financing Activities. The increase in net cash provided by financing activities was primarily due to sales of an aggregate of 2,006,550 shares of our common stock pursuant to the ATM Program for aggregate net proceeds of approximately $19.9 million during the threesix months ended MarchJune 31,30, 2026 .2026. We had no sales pursuant to our ATM Program during the three months ended MarchJune 31,30, 2025.2026. Additional financing activities included proceeds received from the issuance of common stock through our employee stock purchase plan and from employee stock option exercises.

In May 2025, we filed a shelf registration statement on Form S-3 (the 2025 Shelf Registration Statement). The 2025 Shelf Registration Statement permits: (i) the offering, issuance and sale by us of up to a maximum aggregate offering price of $300.0 million of common stock, preferred stock, debt securities and warrants in one or more offerings and in any combination; and (ii) the offering, issuance and sale by us of up to a maximum aggregate offering price of $100.0 million of our common stock that may be issued and sold under our ATM Program. The $100.0 million of common stock that may be issued and sold under the ATM Program is included in the $300.0 million of securities that may be issued and sold under the 2025 Shelf Registration Statement. During the threesix months ended MarchJune 31,30, 2026, we sold an aggregate of 2,006,550 shares of our common stock pursuant to the ATM Program for aggregate net proceeds of approximately $19.9 million. We had no sales pursuant to our ATM Program during the three months ended June 30, 2026. As of June 30, 2026, we had $53.9 million available for future issuances of common stock pursuant to the ATM Program.

For the threesix months ended MarchJune 31,30, 2026, no payments were made pursuant to the License Agreement. In 2022, pursuant to the License Agreement, we paid $0.1 million to WARF upon the acceptance of an IND in the United States. We will be required to make further aggregate milestone payments of up to $17.5 million upon achievement of certain other regulatory and commercial milestones. We may also be required to pay royalties based on annual net product sales in the low single digits on our or our sublicensees’ net product sales on a country-by-country and product-by-product basis, and are subject to a minimum royalty of $0.1 million per calendar year upon first commercial product sale. Further, we may be required to pay sublicense fees in the mid-single digits percentage for fees, royalties or other payments earned from the granting of sublicenses to the WARF patents and know-how. The Company will recognize these milestone payments and royalties when paid or payable. There were no additional payments or royalties recorded through MarchJune 31,30, 2026.

We are responsible for reimbursing WARF for costs incurred in connection with prosecuting and maintaining patent rights that are specific to the License Agreement. Expenses recognized in connection with legal patent fees under this License Agreement were immaterial for the threesix months ended MarchJune 31,30, 2026 and 2025.

During the year ended December 31, 2025, we recorded $0.1 million to research and development expenses related to regulatory milestones, which is included in accrued expenses and other current liabilities as of MarchJune 30, 2026 and December 31, 2026.2025. There were no additional payments or royalties recorded for the threesix months ended MarchJune 31,30, 2026. We may be obligated to make aggregate regulatory milestone payments of up to $0.8 million for each product incorporating licensed patent rights and pay a royalty on worldwide net sales on a product-by-product basis. The Company will recognize these milestone payments and royalties when paid or payable.