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

Since inception, we have incurred significant operating losses. Our net losses were $446.2 million for the year ended December 31, 2025 and $317.4 million for the year ended December 31, 2024 and $235.9 million for the year ended December 31, 2023.2024. As of December 31, 2024,2025, we had an accumulated deficit of $949.9$1.4 million.billion. To date, we have financed our operations with the proceeds raised from the sale of equity securities.securities and borrowing under the Loan Agreement with Hercules. We have devoted substantially all of our financial resources and efforts to research and development. We are still in the early stages of development of our programs and product candidates. Our product candidates are in varying stages of preclinical and clinical development and we have not completed clinical development of any product candidate. We expect to continue to incur significant expenses and operating losses for the foreseeable future. Our operating expenses and net losses may fluctuate significantly from quarter to quarter and year to year. We anticipate that our expenses will increase substantially if and as we:

advance our product candidates for DMD, DM1, DMD, FSHD and Pompe and any additional product candidates we may develop;

Our product candidates are in varying stages of preclinical and clinical development. We have not completed clinical development of any product candidate, and we do not expect that it will be at least a couple of years, if ever, before weto have a product candidate ready for commercialization.commercialization at least until 2027, if ever. To become and remain profitable, we must succeed in developing, obtaining the necessary regulatory approvals for, and eventually commercializing a product or products that generate significant revenue. The ability to achieve this success will require us to be effective in a range of challenging activities, including:

We expect our expenses to increase substantially in connection with our ongoing activities, particularly as we advance the clinical development of DYNE-101z-rostudirsen and DYNE-251,z-basivarsen, and the preclinical and clinical development of DYNE-302, our FSHD product candidate, and DYNE-401, our Pompe disease product candidatecandidate, and DYNE-253, DYNE-245, DYNE-244 and DYNE-255, our product candidates for DMD amenable to skipping exons 53, 45, 44 and 55, respectively, and any additional product candidates we may develop, and arrange for the manufacturing of, and potentially seek marketing approval for any product candidates we may develop. In addition, if we obtain marketing approval for any product candidates we may develop, we expect to incur significant commercialization expenses related to product manufacturing, marketing, sales and distribution. Accordingly, we will need to obtain substantial additional funding in connection with our continuing operations. If we are unable to raise capital when needed, on attractive terms or at all, we may be forced to delay, reduce or eliminate our research and development programs or future commercialization efforts.

As of December 31, 2024, we had cash, cash equivalents and marketable securities of $642.3 million. In addition, in the first quarter of 2025, we issued and sold an aggregate of 10,660,159 shares of our common stock under our at-the-market offering program for aggregate net proceeds of $140.6 million, after deducting commissions and offering expenses payable by us. We believe that our existing cash, cash equivalents and marketable securities, including the net proceeds from sales of common stock under our at-the-market offering program during the first quarter of 2025,securities will enable us to fund our operating expensesexpenses, debt service obligations and capital expenditure requirements at least into the secondfirst halfquarter of 2026.2028. However, we have based thisthese estimateestimates on assumptions that may prove to be wrong, and our operating plan may change as a result of many factors currently unknown to us. As a result, we could deplete our capital resources sooner than we currently expect and could be forced to seek additional funding sooner than planned.

Any additional fundraising efforts may divert our management from their day-to-day activities, which may adversely affect our operations. We cannot be certain that additional funding will be available on acceptable terms, when needed or at all. WeOther than the Loan Agreement with Hercules, we have no committed source of additional capital and, if we are unable to raise additional capital in sufficient amounts, when needed or on terms acceptable to us, we may be required to significantly curtail, delay or discontinue one or more of our research or development programs or the commercialization of any product candidates we may develop, or be unable to expand our operations or otherwise capitalize on our business opportunities, as desired, which could materially affect our business, financial condition and results of operations. We could be required to seek collaborators for product candidates at an earlier stage than otherwise would be desirable or on terms that are less favorable than might otherwise be available or relinquish or license on unfavorable terms our rights to product candidates in markets where we otherwise would seek to pursue development or commercialization ourselves. Any of the above events could significantly harm our business, prospects, financial condition and results of operations and cause the price of our common stock to decline.

Until such time, if ever, as we can generate substantial product revenues, we expect to finance our cash needs through a combination of equity offerings, debt financings, collaborations, strategic alliances and/or licensing arrangements.arrangements, Weand terms loans under our Loan Agreement with Hercules. For example, in June 2025, we entered into the Loan Agreement with Hercules providing for term loans in an aggregate principal amount of up to $275.0 million under multiple tranches, available as follows: (i) an initial term loan tranche funded on the closing date of the Loan Agreement in aggregate principal amount of $100.0 million; (ii) subject to the achievement of specified clinical, regulatory and commercial milestones, three additional term loan tranches totaling up to $115.0 million; and (iii) subject to approval by the Lenders’ investment committee in their discretion, a final term loan tranche of up to $60.0 million. In December 2025, we entered into the First Amendment to the Loan Agreement, or the First Amendment, pursuant to which a second term loan tranche was funded in an aggregate principal amount of $50.0 million. Following entry into the First Amendment and the borrowing of the second term loan tranche, we have two additional term loan tranches we may borrow pursuant to the Loan Agreement, totaling up to $75.0 million, which are available subject to the achievement of specified clinical, regulatory and commercial milestones, and a final term loan tranche of up to $50.0 million, which is available subject to approval by the Hercules investment committee in its discretion. However, if we do not satisfy the specified clinical, regulatory and commercial milestones or the Lenders do not otherwise approve the discretionary tranche, we may not have access to the remaining amounts under the term loans. Other than the Loan Agreement with Hercules, we do not have any committed external source of funds. To the extent that we raise additional capital through the sale of equity or convertible debt securities, our stockholders’ ownership interests will be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect the rights of common stockholders. Any debt financing or preferred equity financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, selling or licensing our assets, making capital expenditures, declaring dividends or encumbering our assets to secure future indebtedness.

Our limited operating history may make it difficult to evaluate our technology and industry and predict our future performance. Our limited history as an operating company makes any assessment of our future success or viability subject to significant uncertainty. We will encounter risks and difficulties frequently experienced by early stageclinical-stage companies in rapidly evolving fields. If we do not address these risks successfully, our business will suffer.

We have a history of cumulative losses and anticipate that we will continue to incur significant losses in the foreseeable future; thus, we do not know whether or when we will generate taxable income necessary to utilize our net operating losses, or NOLs, or research and development tax credit carryforwards. As of December 31, 2024,2025, we had federal NOL carryforwards of $315.7$981.6 million and state NOL carryforwards of $332.2$1.0 million.billion.

In general, under Sections 382 and 383 of the U.S. Internal Revenue Code of 1986, as amended, or the Code, and corresponding provisions of state law, a corporation that undergoes an “ownership change,” generally defined as a greater than 50 percentage point change (by value) in its equity ownership by certain stockholders over a three-year period, is subject to limitations on its ability to utilize its pre-change NOLs and pre-change research and development tax credit carryforwards to offset post-change taxable income. We completed a Section 382 study of transactions in our stock through JanuaryDecember 25,10, 20212025 and concluded that we have experienced ownership changes since inception that we believe under Sections 382 and 383 of the Code will result in limitationlimitations onin our ability to use certain pre-change NOLs and credits. WithWe additionalwill stock issuances during 2024, the Company continuescontinue to analyze the impacts of Section 382.382 from future transactions in our stock. In the future, we may experience additional ownership changes as a result of equity offerings or other changes in the ownership of our stock, some of which are beyond our control. As a result, if, and to the extent that, we earn net taxable income, our ability to use our NOL carryforwards and research and development tax credit carryforwards to offset such taxable income may be subject to limitations.

There is also a risk that due to regulatory changes, such as suspensions on the use of NOLs, or other unforeseen reasons, our existing NOLs could expire or otherwise become unavailable to offset future income tax liabilities. As described below in “Changes in tax laws or regulations or in their implementation or interpretation may adversely affect our business and financial condition,” legislation enacted in 2017, informally titled the Tax Cuts and Jobs Act, or the Tax Act, as amended by the Coronavirus Aid, Relief, and Economic Security Act, or CARES Act, includes changes to U.S. federal tax rates and the rules governing NOL carryforwards that may significantly impact our ability to utilize our NOLs to offset taxable income in the future. In addition, state NOLs generated in one state cannot be used to offset income generated in another state. For these reasons, even if we attain profitability, we may be unable to use a material portion of our NOLs and other tax attributes.

Our product candidates are in varying stages of preclinical and clinical development and we have not completed clinical development of any product candidate. AsWe ado resultnot itexpect willto becomplete the commercialization of any product candidate at least auntil couple of years before we commercialize a product candidate,2027, if ever. If we are unable to identify and advance product candidates through preclinical studies and clinical trials, obtain marketing approval and ultimately commercialize them, or experience significant delays in doing so, our business will be materially harmed.

We have focused our efforts to date on developing our platform, identifying our programs and conducting the clinical development of our product candidates. Our product candidates are in varying stages of preclinical and clinical development, and we have not completed clinical development of any product candidate. Our ability to generate product revenue, which we do not expect will occur foruntil at least a couple of years,2027, if ever, will depend heavily on the successful development and eventual commercialization of our product candidates, which may never occur. We currently generate no revenue from sales of any product, and we may never be able to develop or commercialize a marketable product.

Commencing clinical trials in the United States is subject to acceptance by the U.S. Food and Drug Administration, or FDA, of an IND and finalizing the trial design based on discussions with the FDA and other regulatory authorities. In the event that the FDA requires us to complete additional preclinical studies or we are required to satisfy other FDA requests prior to commencing clinical trials, the start of any future clinical trials may be delayed. Even after we receive and incorporate guidance from the FDA, the FDA could disagree that we have satisfied their requirements to commence any clinical trial or change their position on the acceptability of our trial design or the clinical endpoints selected, which may require us to complete additional preclinical studies or clinical trials or impose stricter approval conditions than we currently expect.

For example, the FDA placed on clinical hold our IND application to initiate a clinical trial of DYNE-251z-rostudirsen in patients with DMD amenable to skipping exon 51. We received a clinical hold letter from the FDA in January 2022 requesting additional clinical and non-clinical information for DYNE-251,z-rostudirsen, which we submitted before the FDA ultimately cleared the IND in July 2022.

In addition, if we are slow or unable to adapt to changes in existing requirements or the adoption of new requirements or policies governing clinical trials, our development plans may be impacted. For example, in December 2022, with the passage of Food and Drug Omnibus Reform Act, or FDORA, Congress required sponsors to develop and submit a Diversity Action Plan, or DAP, for each phase 3 clinical trial or any other “pivotal study” of a new drug or biological product. These plans are meant to encourage the enrollment of more diverse patient populations in late-stage clinical trials of FDA-regulated products. In June 2024, as mandated by FDORA, the FDA issued draft guidance outlining the general requirements for the DAPs. Unlike most guidance documents issued by the FDA, the DAP guidance, when finalized, will have the force of law as FDORA specifically dictates that the form and manner for submission of DAPs are specified in FDA guidance. On January 27, 2025, in response to an Executive Order issued by President Trump on January 21, 2025, on Diversity, Equity and Inclusion programs, the FDA removed this draft guidance from its website. This action raises questions about the applicability of statutory obligations to submit DAPs and the FDA’s current thinking on best practices for clinical development.

The regulatory landscape related to clinical trials in the EUEuropean Union has also evolved. The EU Clinical Trials Regulation, or CTR, which was adopted in April 2014 and repeals the EU Clinical Trials Directive, became applicable on January 31, 2022. While the Clinical Trials Directive required a separate clinical trial application, or CTA, to be submitted in each member state, to both the competent national health authority and an independent ethics committee, the CTR introducesintroduced a centralized process and only requires the submission of a single application to all member states concerned. If we are not able to fulfill these new requirements, our ability to conduct clinical trials may be delayed or halted.

We have not completed clinical development of any product candidate. As a result, our belief in the capabilities of our platform, including our belief that we have demonstrated proof of concept of our FORCE platform, is based on early research, preclinical studies and data from clinical trials of our product candidates. However, the results of preclinical studies may not be predictive of the results of later preclinical studies or clinical trials, and the initial results of any clinical trials, such as initial results of ACHIEVEDELIVER and DELIVERACHIEVE that we have reported, may not be predictive of the final results of those trials or the results of any later clinical trials, and may also not be predictive of results of clinical trials in other indications. Moreover, preclinical and clinical data are often susceptible to varying interpretations and analyses, and many companies that have believed their product candidates performed satisfactorily in preclinical studies and clinical trials have nonetheless failed to obtain marketing approval of their products. Further, certain of our hypotheses regarding the potential benefits of our product candidates compared to alternative therapies and treatments are based on cross-trial comparisons of results that were not derived from head-to-head clinical trials. Such clinical trial data may not be directly comparable due to differences in study protocols, conditions and patient populations. Accordingly, these cross-trial comparisons may not be reliable predictors of the relative efficacy or other benefits of our product candidates compared to other product candidates that may have been approved previously.

Although other oligonucleotide therapeutics have received regulatory approval, our approach for our DM1, DMD and FSHDDM1 programs, which combine oligonucleotides with a Fab, is a novel approach to oligonucleotide therapy. As a result, there is uncertainty as to the safety profile of product candidates we may develop compared to more well-established classes of therapies, or oligonucleotide therapeutics on their own. Moreover, there have been only a limited number of clinical trials involving the use of conjugated oligonucleotide therapeutics.

We do not expect to independently conduct all aspects of our product manufacturing, or our research and preclinical and clinical testing. We currently rely, and expect to continue to rely, on third parties with respect to many of these items, including contract manufacturing organizations, or CMOs, for the manufacturing of any product candidates we test in preclinical or clinical development, as well as CROs for portions of our animal testing, preclinical research and for the conduct of our clinical trials. Any of these third parties may terminate their engagements with us at any time. If we need to enter into alternative arrangements, it could delay our product development activities.

We may from time to time depend on single-source suppliers for some of the components and materials used in any product candidate we may develop. For instance, we currently use a single supplieror limited number of suppliers for each of our Fab, linkers and payloads. We cannot ensure that these suppliers or service providers will remain in business, have sufficient capacity or supply to meet our needs or that they will not be purchased by one of our competitors or another company that is not interested in continuing to work with us. Our use of single-source suppliers of raw materials, components, key processes and finished goods could expose us to several risks, including disruptions in supply, price increases or late deliveries. There are, in general, relatively few alternative sources of supply for substitute components. These vendors may be unable or unwilling to meet our future demands for our clinical trials or commercial sale. Establishing additional or replacement suppliers for these components, materials and processes could take a substantial amount of time and it may be difficult to establish replacement suppliers who meet regulatory requirements. Any disruption in supply from any single-source supplier or service provider could lead to supply delays or interruptions which would damage our business, financial condition, results of operations and prospects.

Currently, patients with DMD are treated with corticosteroids to manage the inflammatory component of the disease. EMFLAZA (deflazacort) is an FDA-approved corticosteroid marketed by PTC Therapeutics, Inc., or PTC.Inc.. A novel steroid, AGAMREE (vamorolone) washas also recentlybeen approved by the FDA for treatment of DMD in patients 2 years of age and older and is marketed by Catalyst Pharmaceuticals, Inc. Givinostat, an HDAC inhibitor, received FDA approval for treatment of DMD in patients 6 years of age and older and is marketed in the U.S.United States by ITF Therapeutics, LLC. In addition, there are four FDA-approved exon skipping drugs: EXONDYS 51 (eteplirsen), VYONDYS 53 (golodirsen) and AMONDYS 45 (casimersen), which are naked PMOs approved for the treatment of DMD patients amenable to exon 51, exon 53 and exon 45 skipping, respectively, and are marketed by Sarepta Therapeutics, Inc., or Sarepta, and VILTEPSO (vitolarsen), a naked PMO approved for the treatment of DMD patients amenable to exon 53 skipping, which is marketed by Nippon Shinyaku Co. Ltd. Additionally, there is one FDA-approved gene therapy for patients with a confirmed mutation in the dystrophin gene, ELEVIDYS (delandistrogene moxeparvovec-rokl), which is marketed by Sarepta. Companies focused on developing treatments for DMD that target dystrophin mechanisms, as does our DMD program, include Wave Life Sciences Ltd. with WVE-N531, a stereopure oligonucleotide being evaluated in a Phase 2 clinical trial for patients amenable to exon 53 skipping; Entrada Therapeutics, Inc. with ENTR-601-44, an endosomal escape vehicle technology for the treatment of DMD patients amenable to exon 44 skippingand exon 45 skipping, respectively, currently being evaluated in a Phase 1/2 clinical trialtrials; Pepgen,BioMarin Inc.,Pharmaceuticals, Inc. with EDO51,BMN-351, aan peptide-linked PMOASO for patients amenable to exon 51 skipping which is being evaluated in a Phase 1/2 clinical trial; BioMarinSQY Pharmaceuticals, Inc.Therapeutics with BMNSQY-51, 351,a anPMO oligonucleotidefor therapypatients thatamenable targetsto dystrophinexon production51 skipping, which is also being evaluated in a Phase 1/2 clinical trial; NS Pharma, Inc. with NS-050/NCNP-03 and NS-089/NCNP-02, which are PMOs in Phase 1/2 and Phase 2 clinical trials for exon-50 and exon 44 skipping amenable DMD respectively; and Avidity with AOCdelpacibart 1044,zotadirsen (formerly known as AOC-1044), an antibody oligonucleotide conjugate that targets dystrophin production for patients amenable to exon 44 skipping being evaluated in a Phase 1/2 clinical trial.trial, which recently reported positive topline data and intent to file for accelerated approval with the FDA in 2026. In addition, several companies are developing gene therapies to treat DMD,DMD are in clinical development, including Milo Biotechnology (AAV1-FS344), Sarepta (SRP-9001 and Galgt2 gene therapy program), Solid Biosciences Inc. (SGT-003), REGENXBIO Inc. (RGX-202), Genethon (GNT-0004), and Insmed Inc. (INS1201). Gene editing treatments that are in preclinical development are also being pursued by Vertex and Sarepta. We are also aware of several companies targeting non-dystrophin mechanisms for the treatment of DMD.

There are currently no therapies approved to treat FSHD. Products currently in development for FSHD include: ARO-DUX4, an siRNA therapy being evaluated in a Phase 1/23 clinical trial and licensed by Arrowhead Pharmaceuticals, Inc. to Sarepta; delpacibart braxlosiran (formerly AOC-1020), an antibody oligonucleotide conjugate being evaluated in a Phase 1/2 clinical trial by Avidity and RO7204239, an anti-latent myostatin antibody by Roche Pharmaceuticals that is in a Phase 2 clinical trial. Additionally, satralizumab,Satralizumab, an anti-IL-6 antibody, is being evaluated in a Phase 1 clinical trial by the University Hospital of Nice and clenbuterol, a beta (2) agonist, is being evaluated in a Phase 2 clinical trial by Springbokthe Analytics,University Hospital of Nice. EpiCrispr Bio is developing an AAV-delivered CRISPR epigenome modification therapy targeting DUX4 that is currently in Phase 1/2 clinical trials. Scholar Rock Holding Corporation cleared its IND application for apitegromab in FSHD with Phase 2 study initiation and patient dosing expected mid-2026. Several other companies have therapies targeting DUX4 in preclinical development (e.g., Facio Biotherapies Pty Ltd, Kate Therapeutics Inc. (acquired by Novartis), Souffle Therapeutics, and Ionis).

There are three currently approved medicines for Pompe disease, all of which are enzyme replacement therapies: Myozyme/Lumizyme (alglucosidase alfa) and Nexviazyme/Nexviadyme (avalglucosidase alfa) by Sanofi, and Pombiliti + Opfolda (cipaglucosidase alfa-atga in combination with miglustat) by Amicus Therapeutics, Inc. Beyond these marketed products, the Pompe clinical pipeline consists of early-stageseveral clinical-stage product candidates that aim to address Pompe disease via alternative strategies. ACTUS-101, a gene therapy delivered to the liver for continuous, endogenous production of GAA currently being evaluated in a Phase 1/2 clinical trial by AskBio. AskBio, Inc.which andis AT-845,wholly owned by Bayer AG, also has its AB-1009 gene therapy program that is in a Phase 1/2 clinical trial in the United States for LOPD. AT-845 is a muscle-targeted gene therapy currently being evaluated in a Phase 1/2 clinical trial by Astellas Pharma US, Inc. for LOPD. In addition, ABX-1100 by ARO Biotherapeutics Co. and MZE-001 by Maze Therapeutics, Inc. are substrate reduction therapies in Phase 1 clinical trials. Denali Therapeutics, Inc. also announced plans to initiate a Phase 1 trial for its enzyme replacement therapy in January 2026.

We also expect to compete more generally with other companies developing alternative scientific and technological approaches to the treatment of muscle diseases, including other companies working to develop conjugates with oligonucleotides for extra-hepatic delivery, including Alnylam Pharmaceuticals, Inc., Aro Biotherapeutics, Inc., Arrowhead Pharmaceuticals, Inc., Avidity, Denali Therapeutics, Inc., Novo Nordisk A/S, DTx Pharma, Inc., Gennao Bio, Inc., Ionis Pharmaceuticals, Inc. and Sarepta, as well as gene therapy and gene editing approaches.

The Patient Protection and Affordable Care Act, as amended by the Health Care and Education Affordability Reconciliation Amendment, or the ACA, includes a subtitle called the Biologics Price Competition and Innovation Act of 2009, or BPCIA, which created an abbreviated approval pathway for biological products that are biosimilar to or interchangeable with an FDA-licensed reference biological product. In December 2022, Congress clarified through The Food and Drug Omnibus Reform ActFDORA that the FDA may approve multiple first interchangeable biosimilar biological products so long as the products are all approved on the first day on which such a product is approved as interchangeable with the reference product.

There is a risk that any product candidates we may develop that are approved as a biological product under a BLA would not qualify for the 12-year period of exclusivity or that this exclusivity could be shortened due to U.S. congressional action or otherwise, or that the FDA will not consider any product candidates we may develop to be reference products for competing products, potentially creating the opportunity for generic competition sooner than anticipated. OtherFurther, aspectsthe FDA may revise the standards governing approval of biosimilars so as to bring such products to the BPCIA,market somemore quickly. For example, in October 2025, the FDA issued draft guidance which proposes to eliminate the need for sponsors of whichbiosimilar may impact the BPCIA exclusivity provisions, have also been the subject of recent litigation. Moreover, the extentproducts to whichconduct comparative human clinical efficacy studies, allowing them to rely instead on analytical testing to demonstrate product differences from a biosimilar, once approved, will be substituted for any one of our reference products in a way that is similar to traditional generic substitution for nonbiological products is not yet clear, and will depend on a number of marketplace and regulatory factors that are still developing.product.

Our success depends in large part on our and our licensors’ ability to obtain and maintain patent and other intellectual property protection in the United States and other jurisdictions. We currently own and license patents and patent applications relating to our FORCE platform technology, including our Fabs, payloads and Fab-payload conjugates, as well as aspects of our manufacturing and methods of treatment. We and our licensors have sought, and will seek, to protect our proprietary position by filing additional patent applications in the United States and abroad related to certain technologies and our platform that are important to our business. However, while much of our patent portfolio is at an early stage, we own thirty-six54 issued U.S. patents and threefourteen granted foreign patents, and exclusively license three issued U.S. patents and one issued European patent. Moreover, there can be no assurance as to whether or when our patent applications will issue as granted patents. Our ability to stop third parties from making, using, selling, marketing, offering to sell, importing and commercializing any product candidates we may develop and our technology is dependent upon the extent to which we have rights under valid and enforceable patents and other intellectual property that cover our platform and technology. If we are unable to secure, maintain, defend and enforce patents and other intellectual property with respect to any product candidates we may develop and technology, it would have a material adverse effect on our business, financial condition, results of operations and prospects.

Our pending Patent Cooperation Treaty, or PCT, patent applications are not eligible to become issued patents until, among other things, we file a national stage patent application within 30 to 32 months, depending on the jurisdiction, from such application’s priority date in the jurisdictions in which we are seeking patent protection. Similarly, our pending provisional patent applications are not eligible to become issued patents until, among other things, we file a non-provisional patent application within 12 months of such provisional patent application’s filing date. If we do not timely file such national stage patent applications or non-provisional patent applications, we may lose our priority date with respect to such PCT or provisional patent applications, respectively, and any patent protection on the inventions disclosed in such PCT or provisional patent applications, respectively. While we and our licensors intend to timely file selected national stage and non-provisional patent applications relating to our PCT and provisional patent applications, respectively, we cannot predict whether any such patent applications will result in the issuance of patents. If we or our licensors do not successfully obtain issued patents, or, if the scope of any patent protection we or our licensors obtain is not sufficiently broad, we will be unable to prevent others from using any product candidates we may develop or our technology or from developing or commercializing technology and products similar or identical to ours or other competing products and technologies. Any failure to obtain or maintain patent protection with respect to our product candidates or our FORCE platform would have a material adverse effect on our business, financial condition, results of operations and prospects.

The patent position of biotechnology and pharmaceutical companies generally is highly uncertain, involves complex legal and factual questions and has, in recent years, been the subject of much litigation. As a result, the issuance, scope, validity, enforceability and commercial value of patent rights are highly uncertain. Our pending and future owned and licensed patent applications may not result in patents being issued which protect our technology or product candidates, effectively prevent others from commercializing competitive technologies and product or otherwise provide any competitive advantage. In fact, patent applications may not issue as patents at all, and even if such patent applications do issue as patents, they may not issue in a form, or with a scope of claims, that will provide us with any meaningful protection, prevent others from competing with us or otherwise provide us with any competitive advantage. In addition, the scope of claims of an issued patent can be reinterpreted after issuance, and changes in either the patent laws or interpretation of the patent laws in the United States and other jurisdictions may diminish the value of our patent rights or narrow the scope of our patent protection. Furthermore, our competitors or other third parties may be able to circumvent our patents by developing similar or alternative technologies or products in a non-infringing manner.

We are and expect to continue to be reliant upon third-party licensors for certain patent and other intellectual property rights that are important or necessary to the development of our technology and product candidates. For example, we are party to a license from the University of Mons, or UMONS,UMONS to certain patent rights and know-how of UMONS. Our license agreement with UMONS imposes, and we expect that any future license agreement will impose, specified diligence, milestone payment, royalty, commercialization, development and other obligations on us and require us to meet development timelines, or to exercise diligent or commercially reasonable efforts to develop and commercialize licensed products, in order to maintain the licenses. For more information on the terms of the license agreement with UMONS, see Item 1. “Business—Intellectual Property—License Agreement with the University of Mons” in this Annual Report on Form 10-K.

In addition to the protection afforded by patents, we rely on trade secret protection and confidentiality agreements to protect proprietary know-how that is not patentable or that we elect not to patent, processes for which patents are difficult to enforce and any other elements of our product candidate discovery and development processes that involve proprietary know-how, information or technology that is not covered by patents. However, trade secrets can be difficult to protect and some courts inside and outside the United States are less willing or unwilling to protect trade secrets. We seek to protect our proprietary technology and processes, in part, by entering into confidentiality agreements with our employees, consultants, scientific advisors, contractors and other parties who have access to such technology and processes. However, we may not be able to prevent the unauthorized disclosure or use of our technical know-how or other trade secrets by the parties to these agreements. Monitoring unauthorized uses and disclosures is difficult, and we do not know whether the steps we have taken to protect our proprietary technologies will be effective. If any of the collaborators, scientific advisors, employees and consultants who are parties to these agreements breach or violate the terms of any of these agreements, we may not have adequate remedies for any such breach or violation. AsIn asuch result, we could lose our trade secrets andcircumstances, third parties could potentially use our trade secrets to compete with any product candidates we may develop and our technology. Additionally, we cannot guarantee that we have entered into such agreements with each party that may have or has had access to our trade secrets or proprietary technology and processes.

In addition, while it is our policy to require our employees and contractors who may be involved in the conception or development of intellectual property to execute agreements assigning such intellectual property to us, we may be unsuccessful in executing such an agreement with each party who, in fact, conceives or develops intellectual property that we regard as our own. Moreover, even when we obtain agreements assigning intellectual property to us, the assignment of intellectual property rights may not be self-executing or the assignment agreements may be breached, and we may be forced to bring claims against third parties, or defend claims that they may bring against us, to determine the ownership of what we regard as our intellectual property. Furthermore, individuals executing agreements with us may have pre-existing or competing obligations to a third party, such as an academic institution, and thus an agreement with us may be ineffective in perfecting ownership of inventions developed by that individual. Disputes about the ownership of intellectual property that we own may have a material adverse effect on our business, financial condition, results of operations and prospects.

Further, under the Pediatric Research Equity Act, or PREA, a new drug application, or NDA, a BLA or supplement to an NDA or BLA for certain drugs and biological products must contain data to assess the safety and effectiveness of the drug or biological product in all relevant pediatric subpopulations and to support dosing and administration for each pediatric subpopulation for which the product is safe and effective, unless the sponsor receives a deferral or waiver from the FDA. A deferral may be granted for several reasons, including a finding that the product or therapeutic candidate is ready for approval for use in adults before pediatric trials are complete or that additional safety or effectiveness data needs to be collected before the pediatric trials begin. The applicable legislation in the EUEuropean Union also requires sponsors to either conduct clinical trials in a pediatric population in accordance with a Pediatric Investigation Plan approved by the Pediatric Committee of the EMA, or to obtain a waiver or deferral from the conduct of these studies by the Pediatric Committee of the EMA. For any of our product candidates for which we seek regulatory approval in the United States or the EU,European Union, we cannot guarantee that we will be able to obtain a waiver or alternatively complete any required studies and other requirements in a timely manner, or at all, which could result in associated reputational harm and subject us to enforcement action.

In addition, our ability to develop and market new drug products may be impacted by litigation challenging the FDA’s approval of mifepristone. In April 2023, the U.S. District Court for the Northern District of Texas invalidated the approval by the FDA of mifepristone, a drug product which was originally approved in 2000 and whose distribution is governed by various measures adopted under a Risk Evaluation and Mitigation Strategy. On appeal, the U.S. Court of Appeals for the Fifth Circuit declined to order the removal of mifepristone from the market, finding that a challenge to the FDA’s initial approval in 2000 is barred by the statute of limitations. But the U.S. Court of Appeals for the Fifth Circuit did holdheld that plaintiffs were likely to prevail in their claim that changes allowing for expanded access of mifepristone that FDA authorized in 2016 and 2021 were arbitrary and capricious and in violation of federal law. In June 2024, the U.S. Supreme Court reversed and remanded that decision after unanimously finding that the plaintiffs did not have standing to bring this legal action against the FDA. On October 11, 2024,Thereafter, the Attorneys General of three states filed an amended complaint in the district court in Texas challenging the FDA's actions. On September 30, 2025, the district court declined to dismiss the case and, instead, transferred it to the federal district court in the Eastern District of Missouri. Depending on the outcome of this litigation, if it continues, our ability to develop new drug product candidates and to maintain approval of any then-existing drug products could be at risk and could be delayed, undermined or subject to protracted litigation.

In March 2023, the FDA issued draft guidance that outlines its current thinking and approach to accelerated approval. The FDA indicated that the accelerated approval pathway is commonly used for approval of oncology drugs due to the serious and life-threatening nature of cancer. Although single-arm trials have been commonly used to support accelerated approval, a randomized controlled trial is the preferred approach as it provides a more robust efficacy and safety assessment and allows for direct comparisons to an available therapy. To that end, the FDA outlined considerations for designing, conducting, and analyzing data for trials intended to support accelerated approvals of oncology therapeutics. Subsequently, in December 2024,2024 and January 2025, the FDA issued additional draft guidanceguidances relating to accelerated approval. While thisthese guidanceguidances isare currently only in draft form and will ultimately not be legally binding even when finalized, we will need to observe the FDA’s guidanceguidances closely to ensure that our products qualify for accelerated approval.

In addition, foreign regulatory authorities may change their approval policies and new regulations may be enacted. For instance, the EU pharmaceutical legislation is currently undergoing a complete review process, in the context of the Pharmaceutical Strategy for Europe initiative, launched by the European Commission in November 2020. The European Commission’s proposal for revision of several legislative instruments related to medicinal products, which may reduce the duration of regulatory data protection and exclusivity periods for orphan drugs, and revise the eligibility for expedited pathways in addition to other changes,products was published in April 20232023. andOn June 4, 2025, after almost two years of negotiations among the EU Member States, the Council of the European ParliamentUnion hasadopted requestedits severalposition amendments.on Thethe proposed revisionsoverhaul remainof tothe beEU agreedgeneral andpharmaceutical adoptedlegislative byframework, which is known as the new Pharma Package. Thereafter, on December 11, 2025, the European Parliament and European Council andreached a provisional political agreement on the proposals may therefore be substantially revised before adoption,legislation which is notexpected anticipatedto beforebe earlyadopted 2026.by mid-2026. The revisions may however have a significant impact on the pharmaceutical industry and our businessbusiness. They would, among other things, set a baseline period of 8 years of data exclusivity and one year of market exclusivity with possible extensions for new indications up to a maximum of 11 years total. There will likely be a transition period, with the changes taking effect in the long term.mid-2028.

If any product candidate we may develop is intended for the treatment of a serious or life-threatening condition and the product candidate demonstrates the potential to address unmet medical need for this condition, we may apply for FDA Fast Track designation. In October 2022, the FDA granted Fast Track designation for DYNE-251,z-rostudirsen, and in January 2025, the FDA granted Fast Track designation for DYNE-101.z-basivarsen. However, a Fast Track designation does not ensure that the product candidate will receive marketing approval or that approval will be granted within any particular timeframe. As a result, while we may seek and receive Fast Track designation for any product candidates we may develop, we may not experience a faster development process, review or approval compared to conventional FDA procedures. In addition, the FDA may withdraw Fast Track designation if it believes that the designation is no longer supported by data from our clinical development program. Fast Track designation alone does not guarantee qualification for the FDA’s priority review procedures.

If any product candidate we may develop is intended, either alone or in combination with one or more other products, to treat a serious or life-threatening disease or condition and preliminary clinical evidence indicates that the product may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints, such as substantial treatment effects observed early in clinical development, the sponsor may apply for FDA breakthrough designation or a regenerative medicine advanced therapy, or RMAT, designation. In June 2025, the FDA granted Breakthrough Therapy Designation to z-basivarsen for the treatment of DM1. Additionally, in August 2025, the FDA granted Breakthrough Therapy Designation to z-rostudirsen for the treatment of DMD, amenable to exon 51 skipping. However, neither a breakthrough designation nor an RMAT designation ensures that the product candidate will receive marketing approval or that approval will be granted within any particular timeframe. As a result, while we may seek and receive breakthrough or RMAT designation for any product candidates we may develop, we may not experience a faster development process, review or approval compared to conventional FDA procedures. In addition, the FDA may withdraw breakthrough or RMAT designation if it believes that the designation is no longer supported by data from our clinical development program. Neither breakthrough nor RMAT designation alone guarantees qualification for the FDA’s priority review procedures.

We are a clinical-stage neuromuscular disease company focused on discoveringdelivering andfunctional advancing innovative life-transforming therapeuticsimprovement for people living with genetically driven neuromuscular diseases. LeveragingOur the modularity of ourproprietary FORCE platform,platform we are developing targeted therapeutics that areis designed to overcomeleverage limitationsthe intransferrin deliveryreceptor 1, or TfR1, to deliver targeted therapeutics to muscle tissue and the central nervous system, or CNS. Our proprietaryThe FORCE platform therapeuticsutilizes consistan ofantigen-binding fragment antibody, or Fab, targeting TfR1 conjugated to a payload that we rationally design to target the genetic basis of the disease we are seeking to treat, a linker and an antigen-binding fragment, or Fab, that we attach to the payload using the linker.treat. With our FORCE platform, we have the flexibility to deploy different classes of payloads (such as oligonucleotides and enzymes) with specific mechanisms of action that modify target functions. We currently leverage this modularity to focus on neuromuscular diseases with high unmet need, with etiologic targets and with clear translational potential from preclinical disease models to well-defined clinical development and regulatory pathways.

Using our FORCE platform, we are assembling a broad portfolio of product candidates, including product candidates being developed for Duchenne muscular dystrophy, or DMD, myotonic dystrophy type 1, or DM1, Duchenne muscular dystrophy, or DMD, facioscapulohumeral dystrophy, or FSHD, and Pompe disease. In addition, we plan to expand our portfolio through development efforts focused on diseases involving the CNS, rare skeletal muscle diseases, as well asand cardiac and metabolic muscle diseases, including some with larger patient populations, and diseases involving the CNS.populations. We have identified product candidates for each of our DMD, DM1, DMD, FSHD and Pompe programs that are in varying stages of preclinical and clinical development.

We were incorporated and commenced operations in 2017. Since our incorporation, we have devoted substantially all of our financial resources and efforts to organizing and staffing our company, business planning, raising capital, conducting research and development activities and filing and prosecuting patent applications. We do not have any products for sale and have not generated any revenue from product sales or otherwise. To date, we have principally raised capital through sales of equity securities.securities and our borrowing under our Loan and Security Agreement, or the Loan Agreement, with Hercules Capital, Inc., or Hercules.

Since our inception, we have incurred significant operating losses. Our ability to generate any product revenue or product revenue sufficient to achieve profitability will depend on the successful development and eventual commercialization of one or more product candidates. For the years ended December 31, 2024,2025, 20232024 and 2022,2023, we reported net losses of $317.4$446.2 million, $235.9$317.4 million and $168.1$235.9 million, respectively. As of December 31, 2024,2025, we had an accumulated deficit of $949.9$1.4 million.billion.

advance our product candidates for DMD, DM1, DMD, FSHD and Pompe and conduct research programs in additional indications;

As a result, we will need substantial additional funding to support our continuing operations and pursue our growth strategy. Until such time as we can generate significant revenue from product sales, if ever, we expect to finance our operations through a combination of equity offerings, debt financings, collaborations, strategic alliances and licensing arrangements.arrangements, and terms loans under our Loan Agreement with Hercules. We may be unable to raise additional funds or enter into such other agreements or arrangements when needed, on favorable terms, or at all. If we fail to raise capital or enter into such agreements or arrangements as and when needed, we may have to significantly delay, reduce or eliminate the development or future commercialization of one or more product candidates we may develop.

We believe that our existing cash, cash equivalents and marketable securities, including the net proceeds from sales of common stock under our at-the-market offering program during the first quarter of 2025, will enable us to fund our operating expenses and capital expenditure requirements into the second half of 2026. We have based our estimatesestimate as to how long we expect we will be able to fund our operationsoperations, debt service obligations and capital expenditure requirements on assumptions that may prove to be wrong. We could use our available capital resources sooner than we currently expect, in which case we would be required to obtain additional financing, which may not be available to us on acceptable terms, or at all. Our failure to raise capital as and when needed would have a negative impact on our financial condition and our ability to pursue our business strategy. See “—Liquidity and capital resources” below. These estimates do not give effect to any additional funding tranches we may obtain access to under our Loan Agreement with Hercules, subject to the achievement of specified clinical, regulatory and commercial milestones, and do not give effect to any revenue we may generate on commercial sales of any products for which we obtain regulatory approval.

We have not generated any revenue since our inception and do not expect to generate any revenue from the sale of products foruntil at least a couple of years,2027, if at all. If our development efforts are successful and we commercialize products, or if we enter into collaboration or license agreements with third parties, we may generate revenue in the future from product sales, as well as upfront, milestone and royalty payments from such collaboration or license agreements, or a combination thereof.

Product candidates in later stages of clinical development generally have higher development costs than those in earlier stages of clinical development, primarily due to the increased size and duration of later-stage clinical trials. Accordingly, we expect that our research and development expenses will increase substantially as we advance DYNE-101z-rostudirsen and DYNE-251z-basivarsen through clinical trials, in connection with our preclinical and clinical development activities of DYNE-302, our FSHD product candidate, and DYNE-401, our Pompe disease product candidate, and if and as we advance any other product candidates through preclinical studies and clinical trials. At this time, we cannot accurately estimate or know the nature, timing and costs of the efforts that will be necessary to complete the preclinical and clinical development of any product candidates we may develop. The successful development of any product candidate is highly uncertain. This is due to the numerous risks and uncertainties associated with product development, including the following:

General and administrative expenses consist primarily of employee-related expenses, including salaries, related benefits and stock-based compensation for employees in executive, finance, corporate and business developmentdevelopment, commercial and administrative functions. General and administrative expenses also include legal fees relating to patent and corporate matters; professional fees for accounting, auditing, tax and administrative consulting services; insurance costs; administrative travel expenses; commercial readiness activities; and facility-related expenses, which include allocated expenses for rent, depreciation and maintenance of facilities and other operating costs.

Since our inception, we have not recorded any U.S. federal or state income tax benefits for the net losses we have incurred in any year or for our earned research and development tax credits, due to our uncertainty of realizing a benefit from those items. As of December 31, 2024,2025, we had federal and state net operating loss carryforwards of $315.7$981.6 million and $332.2$1.0 million,billion, respectively. The federal net operating loss carryforwards are indefinite lived and the state net operating loss carryforwards begin to expire in 2038. As of December 31, 2024,2025, we also had federal and state research and development tax credit carryforwards of $31.2$49.0 million and $4.7$6.2 million which begin to expire in 2039 and 2033, respectively.

Discussion and analysis of the results of operations for the year ended December 31, 20232024 as compared to the results of operations for the year ended December 31, 20222023 is included under the heading “Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations” in our Annual Report on Form 10-K for the year ended December 31, 20232024, as filed with the SEC on MarchFebruary 5,27, 2024.2025.

Since our inception, we have incurred significant operating losses. We expect to incur significant expenses and operating losses for the foreseeable future as we support our continued research activities and development of our product candidates and platform. We have not yet commercialized any product candidates, and we do not expect to generate revenue from sales of any product candidates foruntil at least a couple of years,2027, if at all. To date, we have funded our operations primarily with proceeds from sales of equity securities.securities and our borrowing under the Loan Agreement with Hercules. As of December 31, 2024,2025, we had cash, cash equivalents and marketable securities of $642.3$1.1 million.billion.

In November 2021, we entered into an Open Market Sale AgreementSM, or the Sales Agreement, with Jefferies LLC, or Jefferies. On March 5, 2024, we filed a universal shelf registration statement on Form S-3, or the 2024 Shelf Registration Statement, and included a prospectus relatingpursuant to the Sales Agreement. Under the 2024 Shelf Registration Statement,which we may offer and sell debt securities, common stock, preferred stock, units and/or warrants from time to time at an indeterminate aggregate offering price in one or more offerings. In November 2024, we filed a prospectus supplement relating to the Sales Agreement, pursuant to which, in accordance with the Sales Agreement, we may offer and sell shares of our common stock having an aggregate offering price of up to $300.0 millionmillion, inwhich we refer to as our at-the-market offering program. Sales of common stock under the Sales Agreement through Jefferies may be made by any method that is deemed an “at-the-market” offering as defined in Rule 415(a)(4) under the Securities Act.

In MayJuly 2024,2025, we completed a follow-on public offering, which we refer to as the May 2024 offering, pursuant to which we issued and sold 12,075,00027,878,788 shares of our common stock. We received net proceeds from the offering of $351.3$215.8 million, after deducting underwriting discounts and commissions and offering expenses payablepaid by us.

In the first quarter ofDecember 2025, we completed a follow-on public offering, pursuant to which we issued and sold 10,660,15921,827,549 shares of our common stock through our at-the-market offering program pursuant to the Sales Agreement.stock. We received net proceeds from the offering of $140.6$377.7 million, after deducting underwriting discounts and commissions and offering expenses payablepaid by us.

During the year ended December 31, 2025, operating activities used $403.2 million of cash, due to our net loss of $446.2 million and changes in our operating assets and liabilities of $3.4 million, partially offset by non-cash charges of $46.4 million. Net cash used in changes in our operating assets and liabilities primarily consisted of a $12.6 million increase in non-current assets, partially offset by an $8.3 million increase in accounts payable and other liabilities and a $1.0 million decrease in prepaid expenses and other current assets. During the year ended December 31, 2024, operating activities used $292.4 million of cash, due to our net loss of $317.4 million and changes in our operating assets and liabilities of $19.5 million, partially offset by non-cash charges of $44.5 million. Net cash used in changes in our operating assets and liabilities primarily consisted of a $9.0 million decrease in accounts payable and other liabilities and a $10.5 million increase in prepaid expenses and other current assets. During the year ended December 31, 2023, operating activities used $188.2 million of cash, due to our net loss of $235.9 million partially offset by changes in our operating assets and liabilities of $26.3 million and non-cash charges of $21.4 million. Net cash used by changes in our operating assets and liabilities primarily consisted of a $23.0 million increase in accounts payable and other liabilities and a $3.3 million decrease in prepaid expenses and other current assets. Changes in our operating assets and liabilities during these periods were generally due to the growth of our business, increased clinical trial activity, increased manufacturing activities, advancement of our product candidates, the timing of vendor invoices and payments and annual bonus payments.

Since inception, we have incurred significant operating losses. Our net losses were $120.9$299.4 million and $115.4$226.2 million for the threesix months ended MarchJune 31,30, 2026 and 2025, respectively, and $446.2 million for the year ended December 31, 2025. As of MarchJune 31,30, 2026, we had an accumulated deficit of $1.5$1.7 billion. To date, we have financed our operations with the proceeds raised from the sale of equity securities and our initial borrowingborrowings under the Loan Agreement with Hercules. We have devoted substantially all of our financial resources and efforts to research and development. Our product candidates are in varying stages of preclinical and clinical development and we have not completed clinical development of any product candidate. We expect to continue to incur significant expenses and operating losses for the foreseeable future. Our operating expenses and net losses may fluctuate significantly from quarter to quarter and year to year. We anticipate that our expenses will increase substantially if and as we:

We are only in the preliminary stages of most of these activities. We may never succeed in these activities and, even if we do, may never generate revenues that are significant enough to achieve profitability. Our product candidates are in varying stages of preclinical and clinical development, and we have not completed clinical development of any product candidate. Because of the numerous risks and uncertainties associated with product development, we are unable to accurately estimate or know the nature, timing or costs of the efforts that will be necessary to complete the preclinical and clinical development and commercialization of any product candidate we may develop or when, or if, we will be able to generate revenues or achieve profitability.

We expect our expenses to increase substantially in connection with our ongoing activities, particularly as we seek regulatory approval of and prepare for the potential commercial launch of z-rostudirsen, advance the clinical development of z-rostudirsen and z-basivarsen, and the preclinical and clinical development of DYNE-302, our FSHD product candidate, DYNE-401, our Pompe disease product candidate, and DYNE-253, DYNE-245, DYNE-244 and DYNE-255, our product candidates for DMD amenable to skipping exons 53, 45, 44 and 55, respectively, and any additional product candidates we may develop, and arrange for the manufacturing of, and potentially seek marketing approval for any product candidates we may develop. In addition, if we obtain marketing approval for any product candidates we may develop, we expect to incur significant commercialization expenses related to product manufacturing, marketing, sales and distribution. Accordingly, we will need to obtain substantial additional funding in connection with our continuing operations. If we are unable to raise capital when needed, on attractive terms or at all, we may be forced to delay, reduce or eliminate our research and development programs or future commercialization efforts.

We believe that our existing cash, cash equivalents and marketable securities as of June 30, 2026, as well as the approximately $405.0 in net proceeds from the July 2026 offering, will enable us to fund our operating expenses, debt service obligations and capital expenditure requirements into the firstsecond quarter of 2028. However, we have based these estimates on assumptions that may prove to be wrong, and our operating plan may change as a result of many factors currently unknown to us. As a result, we could deplete our capital resources sooner than we currently expect and could be forced to seek additional funding sooner than planned.

Until such time, if ever, as we can generate substantial product revenues, we expect to finance our cash needs through a combination of equity offerings, debt financings, collaborations, strategic alliances and/or licensing arrangements, and terms loans under our Loan Agreement with Hercules. For example, in June 2025, we entered into the Loan Agreement with Hercules and the other lenders party thereto, which we refer to as the Lenders, and in December 2025, we entered into the First Amendment to the Loan Agreement, or the First Amendment, and in June 2026, we entered into the Second Amendment to the Loan Agreement, or the Second Amendment. The Loan Agreement, as amended by the First Amendment and the Second Amendment, provides for term loans in an aggregate principal amount of up to $275.0$400.0 million under multiple tranches, available as follows: (i) an initial term loan tranche funded on the closing date of the Loan Agreement in aggregate principal amount of $100.0 million; (ii) subject to the achievement of specified clinical, regulatory and commercial milestones, and after the borrowing of the second term loan tranche of $50.0 million in December 2025,2025 twoand the third term loan tranche of $50.0 million in June 2026, three additional term loan tranches totaling up to $75.0$125.0 million; and (iii) subject to approval by the Lenders’ investment committee in their discretion, a final term loan tranche of up to $50.0$75.0 million. However, if we do not satisfy the specified clinical, regulatory and commercial milestones or the Lenders do not otherwise approve the discretionary tranche, we may not have access to the remaining amounts under the term loans. Other than the Loan Agreement with Hercules, we do not have any committed external source of funds. To the extent that we raise additional capital through the sale of equity or convertible debt securities, our stockholders’ ownership interests will be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect the rights of common stockholders. Any debt financing or preferred equity financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, selling or licensing our assets, making capital expenditures, declaring dividends or encumbering our assets to secure future indebtedness.

On June 27, 2025, we entered into the Loan Agreement with Hercules and the Lenders, and in December 2025, we entered into the First Amendment and in June 2026 we entered into the Second Amendment. Following entry into the FirstSecond Amendment and the borrowing of the initialinitial, second and secondthird term loan tranches, we have twothree additional term loan tranches we may borrow pursuant to the Loan Agreement, totaling up to $75.0$125.0 million, which are available subject to the achievement of specified clinical, regulatory and commercial milestones, and a final term loan tranche of up to $50.0$75.0 million, which is available subject to approval by the Lenders’ investment committee in their discretion. Our obligations under the Loan Agreement are secured by a first-priority security interest in substantially all of our property, inclusive of intellectual property, subject to customary permitted liens and other exceptions set forth in the Loan Agreement.

The Loan Agreement contains customary representations and warranties, events of default and affirmative and negative covenants, including a minimum cash covenant, which we refer to as the Minimum Cash Covenant, requiring that we maintain specified levels of cash in accounts subject to a control agreement in favor of Hercules, or the Qualified Cash, during the period commencing on JanuaryJuly 1, 2027. The Minimum Cash Covenant will initially beis set at 60%40% of the then outstanding obligations under the Loan Agreement,Agreement and is subject to adjustment and will notonly be tested at any time whenif our market capitalization is greaterless than $1.65 billion. We are also required to maintain minimum net product revenue from the sale of z-rostudirsen and z-basivarsen starting nine months after FDA approval of z-rostudirsen or z-basivarsen, which we refer to as the Minimum Revenue Covenant, if the outstanding obligations under the Loan Agreement exceed $100.0 million. The Minimum Revenue Covenant will not be tested for any month to the extent that for each day during such month either (i) Qualified Cash is at least 100% of our outstanding obligations under the Loan Agreement or (ii) our market capitalization is greater than $1.65 billion and Qualified Cash is at least 50% of our outstanding obligations under the Loan Agreement. Certain negative covenants under the Loan Agreement limit our ability, among other things, to incur future debt, grant liens, make investments, make acquisitions, distribute dividends, enter into transactions with affiliates, make payments on other indebtedness and sell assets, subject in each case to certain exceptions. Our business may be adversely affected by these restrictions on our ability to operate our business. If we raise any additional debt financing, as permitted by the Loan Agreement, the terms of such additional indebtedness could further restrict our operating and financial flexibility.

We do not own or operate manufacturing facilities and have no current plans to develop our own clinical or commercial-scale manufacturing capabilities. In the future, we may seek to establish our own manufacturing facility for the long-term commercial supply of any product candidates we may develop and which receive regulatory approval. We rely on a small number of third-party suppliers for the manufacture of our Fab, linkers and payloads. We expect to continue to depend on third-party suppliers for the manufacture of any product candidates that we evaluate in preclinical studies and clinical trials, as well as for commercial manufacture if those product candidates receive marketing approval. The facilities used by third-party manufacturers to manufacture our product candidates must be approved by the FDA and any comparable foreign regulatory authority pursuant to inspections that will be conducted after we submit a biologics license application, or BLA, to the FDA or any comparable filing to a foreign regulatory authority. We do not control the manufacturing process of, and are completely dependent on, third-party manufacturers for compliance with cGMPcurrent good manufacturing practice, or cGMP, requirements for manufacture of products. If these third-party manufacturers cannot successfully manufacture material that conforms to our specifications and the strict regulatory requirements of the FDA or any comparable foreign regulatory authority, they will not be able to secure and/or maintain regulatory approval for their manufacturing facilities.

We may compete with third parties for access to manufacturing facilities. There are a limited number of manufacturers that operate under cGMP regulations and that might be capable of manufacturing for us. Further, government action or new legislation could place limitations on our ability to rely on certain counterparties, or make it more expensive.

We do not currently have arrangements in place for redundant supply or a second source for all required raw materials.materials and manufacturing services. If our existing or future third-party manufacturers cannot perform as agreed, we may be required to replace such manufacturers and we may be unable to replace them on a timely basis or at all.

Currently, patients with DMD are treated with corticosteroids to manage the inflammatory component of the disease. EMFLAZA (deflazacort) is an FDA-approved corticosteroid marketed by PTC Therapeutics, Inc..Inc. A novel steroid, AGAMREE (vamorolone) has also been approved by the FDA for treatment of DMD in patients 2 years of age and older and is marketed by Catalyst Pharmaceuticals, Inc. Givinostat, ana HDAChistone deacetylase inhibitor, received FDA approval for treatment of DMD in patients 6 years of age and older and is marketed in the United States by ITF Therapeutics, LLC. In addition, there are four FDA-approved exon skipping drugs: EXONDYS 51 (eteplirsen), VYONDYS 53 (golodirsen) and AMONDYS 45 (casimersen), which are naked PMOsphosphorodiamidate morpholino oligomers, or PMOs, approved for the treatment of DMD patients amenable to exon 51, exon 53 and exon 45 skipping, respectively, and are marketed by Sarepta Therapeutics, Inc., or Sarepta, and VILTEPSO (vitolarsenviltolarsen), a naked PMO approved for the treatment of DMD patients amenable to exon 53 skipping, which is marketed by Nippon Shinyaku Co. Ltd. Additionally, there is one FDA-approved gene therapy for patients with a confirmed mutation in the dystrophin gene, ELEVIDYS (delandistrogene moxeparvovec-rokl), which is marketed by Sarepta.Sarepta, and now restricted for use in ambulatory patients only. Companies focused on developing treatments for DMD that target dystrophin mechanisms, as does our DMD program, include Wave Life Sciences Ltd. with WVE-N531, a stereopure oligonucleotide being evaluated in a Phase 2 clinical trial for patients amenable to exon 53 skipping; Entrada Therapeutics, Inc. with ENTR-601-44,ENTR-601-44 and -45, an endosomal escape vehicle technology for the treatment of DMD patients amenable to exon 44 and exon 45 skipping, respectively, currently being evaluated in Phase 1/2 clinical trials (and candidates for exon 50 and 51 planned for clinical trials); BioMarin Pharmaceuticals, Inc. with BMN-351, an ASOantisense oligonucleotide, or ASO, for patients amenable to exon 51 skipping which is being evaluated in a Phase 1/2 clinical trial; SQY Therapeutics SASU with SQY-51, a PMO for patients amenable to exon 51 skipping, which is also being evaluated in a Phase 1/2 clinical trial; and NS Pharma, Inc. with NS-050/NCNP-03 and NS-089/NCNP-02, which are PMOs in Phase 1/2 and Phase 2 clinical trials for exon-50 and exon 44 skipping amenable DMD respectively; andrespectively. Avidity Biosciences, Inc., or Avidity (acquired by Novartis in February 2026), filed a BLA with the FDA in June 2026 for accelerated approval of delpacibart zotadirsen (formerly known as AOC-1044), an antibody oligonucleotide conjugate for patients amenable to exon 44 skipping being evaluated in a Phase 1/2 clinical trial, which recently reported positive topline data and intent to file for accelerated approval with the FDA in 2026.skipping. In addition, gene therapies to treat DMD are in clinical development, including Solid Biosciences Inc. (SGT-003), and REGENXBIO Inc. (RGX-202), which have both recently reported positive data from their clinical trials as well as an intent to file for approval with the FDA in 2027. Genethon (GNT-0004), and Insmed Inc. (INS1201). are gene therapy programs in Phase 1 development. Capricor Therapeutics’ BLA application for its cell therapy deramiocel is currently under FDA review and an FDA Advisory Committee meeting is scheduled for July 29, 2026 prior to the PDUFA date of August 22, 2026. Precision Biosciences has initiated a Phase 1/2 trial for its PBGENE-DMD gene editing therapy for patients whose mutations are contained between exons 45-55. Gene editing treatments that are in preclinical development are also being pursued by Vertex and Sarepta. We are also aware of several companies targeting non-dystrophin mechanisms for the treatment of DMD.DMD (Satellos with its oral AAK1 inhibitor SAT-3247 in Phase 2 and Edgewise with its oral myosin inhibitor sevasemten currently being developed for Becker, which could also be developed in DMD).

There are currently no approved therapies to treat the underlying cause of DM1. Product candidates currently in clinical development to treat DM1 include: tideglusib, a GSK3-ß inhibitor in late-stage clinical development byfrom AMO Pharma Ltd.that foris childrenset andto adultsstart witha Phase 3 trial in congenital DM1; pitolisant, a selective histamine 3 receptor antagonist / inverse agonist being evaluated in a Phase 2 clinical trial for non-muscular symptoms of DM1 by Harmony Biosciences Holdings, Inc.; delpacibart etedesiran (formerly AOC-1001), an antibody-linked siRNA being evaluated in athe Phase 3 HARBOR clinical trial by Avidity (recently acquired by Novartis); PGN-EDODM1, a peptide-linked PMO, currently being evaluated in a Phase 1 clinical trial by Pepgen, Inc.; ARO-DM1, a peptide-linked siRNA being evaluated in a Phase 1/2a clinical trial in Australia and New Zealand by Arrowhead Pharmaceuticals, Inc.; ATX-01, a lipophilic peptide conjugated anti-miR designed to target microRNA 23b currently being evaluated in a Phase 1/2 clinical trial by ARTHEx Biotech S.L.; VX-670, an endosomal escape vehicle technology with a CUG steric blocker oligonucleotide by Entrada Therapeutics, Inc. in collaboration with Vertex being evaluated in a Phase 1/2 clinical trial in Canada, the United Kingdom, the European Union and Australia; SAR446268, an AAV-medicatedadeno-associated virus, or AAV, -mediated gene therapy currently being evaluated in a Phase 1/2 clinical trial by Sanofi S.A., or Sanofi, in the United States and Argentina; and JUV-161, an AKT-signaling activator currently in a Phase 1 single-ascending dose clinical trial in healthy volunteers by Juvena in Australia. Design Therapeutics also initiated a Phase 1 study of DT-818, a DMPK-targeting small molecule, in January 2026.

There are currently no therapies approved to treat FSHD. Products currently in development for FSHD include: ARO-DUX4, an siRNA therapy being evaluated in a Phase 31/2 clinical trial and licensed by Arrowhead Pharmaceuticals, Inc. to Sarepta; delpacibart braxlosiran (formerly AOC-1020), an antibody oligonucleotide conjugate being evaluated in a Phase 1/23 clinical trial by Avidity and(acquired by Novartis in February 2026). RO7204239, an anti-latent myostatin antibody by Roche PharmaceuticalsPharmaceuticals, thatwas isdiscontinued in March 2026 after the drug failed to demonstrate a statistically significant benefit over placebo in its Phase 2 clinical trial. Satralizumab, an anti-IL-6 antibody, is being evaluated in a Phase 2 clinical trial by the University Hospital of Nice. EpiCrispr Bio is developing an AAV-delivered CRISPR epigenome modification therapy targeting DUX4 that is currently in Phase 1/2 clinical trials. Scholar Rock Holding Corporation clearedplans to initiate its INDPhase application2 FORGE study for apitegromab (a mAb targeting latent myostatin) in FSHD with Phase 2 study initiation and patient dosing expectedin mid-2026. Several other companies have therapies targeting DUX4 in preclinical development (e.g., Facio Biotherapies Pty Ltd, Kate Therapeutics Inc. (acquired by Novartis), Souffle Therapeutics, Inc., or Souffle, Satellos Bioscience Inc., Altay Therapeutics Inc., and Ionis Pharmaceuticals, Inc., or Ionis). Souffle in particular has announced plans to initiate its first-in-human trial for SFL-0821 (muscle-targeted siRNA) before the end of 2026. In addition, there are other modalities in development, such as Restem-L, a cell therapy in Phase 1/2a looking to target immune cell infiltration and inflammation in the skeletal muscle.

There are three currently approved medicines for Pompe disease, all of which are enzyme replacement therapies: Myozyme/Lumizyme (alglucosidase alfa) and, Nexviazyme/Nexviadyme (avalglucosidase alfa) by Sanofi, and Pombiliti + Opfolda (cipaglucosidase alfa-atga in combination with miglustat) by Amicus Therapeutics, Inc. Beyond these marketed products, the Pompe clinical pipeline consists of several clinical-stage product candidates that aim to address Pompe disease via alternative strategies. ACTUS-101, a gene therapy delivered to the liver for continuous, endogenous production of GAAGAA, is currently being evaluated in a Phase 1/2 clinical trial by AskBio.AskBio Inc., or AskBio, which is wholly owned by Bayer AG, and which also has its AB-1009a gene therapy program called AB-1009 that is in a Phase 1/2 clinical trial in the United States for late onset Pompe disease, or LOPD. AT-845 is a muscle-targeted gene therapy currently being evaluated in a Phase 1/2 clinical trial by Astellas Pharma US, Inc. for LOPD. Shionogi announced the first patient was enrolled in its global Phase 2 ESPRIT trial of S-606001 (previously known as MZE-001 from Maze Therapeutics, Inc.), a substrate-reduction therapy, in adults with LOPD, in March 2026. In addition, ABX-1100 by ARO Biotherapeutics Co.Co., andis MZE-001 by Maze Therapeutics, Inc. area substrate reduction therapiestherapy in Phase 1 clinical trials. Denali Therapeutics, Inc. also announced plans to initiateinitiated a Phase 1 trial for its enzyme replacement therapy in JanuaryMay 2026. Lastly, GeneCradle Inc. has an ongoing Phase 1/2 trial for its gene therapy in China that is expected to conclude by the end of 2026.

In the future, we may build a sales and marketing infrastructure to market some of the product candidates we develop or may develop if and when they are approved. There are risks involved with establishing our own sales, marketing and distribution capabilities. For example, recruiting and training a sales force is expensive and time-consuming and could delay any product launch. If the commercial launch of a product candidate for which we recruit a sales force and establish marketing capabilities is delayed or does not occur for any reason, we would have prematurely or unnecessarily incurred these commercialization expenses. These efforts may be costly, and our investment would be lost if we cannot retain or reposition our sales and marketing personnel.

Even if we eventually complete clinical testing and receive approval of a BLA or foreign marketing application for any product candidates, the FDA or the comparable foreign regulatory authority may grant approval or other marketing authorization contingent on the performance of costly additional clinical trials, including post-market clinical trials. The FDA or the comparable foreign regulatory authority also may approve or authorize for marketing a product candidate for a more limited indication or patient population thatthan we originally request, and the FDA or comparable foreign regulatory authority may not approve or authorize the labeling that we believe is necessary or desirable for the successful commercialization of a product candidate. Any of these restrictions or commitments could render an approved product not commercially viable, which would materially adversely impact our business and prospects.

Additionally, we could face heightened risks with respect to obtaining marketing authorization in the United Kingdom as a result of the withdrawal of the United Kingdom from the European Union, commonly referred to as Brexit. The United Kingdom is no longer part of the European Single Market and EU Customs Union. As of January 1, 2025, the MHRAMedicines and Healthcare products Regulatory Agency, or the MHRA, is responsible for approving all medicinal products destined for the United Kingdom market (i.e., Great Britain and Northern Ireland). On April 28, 2025, the U.K. Parliament adopted amendments to improve and strengthen the U.K.’s clinical trials regulatory regime; they will take effect on April 28, 2026. These changes were needed since the current U.K. requirements are based upon the now-repealed EU Clinical Trials Directive (2001/20/EC), which has been replaced by the European Clinical Trials Regulation (Regulation EU No 536/2014). Since the United Kingdom left the European Union prior to the date on which the EU CTR took effect, the UK legal framework did not benefit from the same revisions as occurred at EU level.

If the FDA determines that a product candidate we may develop offers major advances in treatment or provides a treatment where no adequate therapy exists, the FDA may designate the product candidate for priority review. A priority review designation means that the goal for the FDA to review an application is six months, rather than the standard review period of ten months. We may request priority review for any product candidates we may develop,develop. Our expectations regarding the timeline for the potential commercial launch of z-rostudirsen reflect that z-rostudirsen was granted priority review by the FDA, and our expectations regarding the timelinestimeline for the potential commercial launcheslaunch of z-rostudirsen and z-basivarsen contemplate theirits receipt of priority review by the FDA. However, the FDA has broad discretion with respect to whether or not to grant priority review status to a product candidate, so even if we believe a particular product candidate we may develop is eligible for such designation or status, the FDA may decide not to grant it. Moreover, a priority review designation does not necessarily mean a faster regulatory review process or necessarily confer any advantage with respect to approval compared to conventional FDA procedures. Receiving priority review from the FDA does not guarantee approval within the six-month review cycle or thereafter.

On June 17, 2025, the FDA announced the creation of a new voucher program to expedite the development and approval of new drug products. Vouchers issued under the new program, which is known as the Commissioner’s National Priority Voucher, or CNPV, Program, may reportedly be redeemed by sponsors to shorten the review time of a BLA from approximately 10 to 12 months to 1 to 2 months. The FDA has indicated that the new CNPV process will convene experts from the FDA’s offices for a team-based review rather than using the standard review system of a drug application being sent to numerous FDA offices. Clinical information will be reviewed by a multidisciplinary team of physicians and scientists who will pre-review the submitted information and convene for a 1-day meeting. Vouchers under this program will reportedly be given to companies aligned with U.S. national priorities. As of AprilMay 1,8, 2026, the FDA has issued 1821 vouchers and approved 57 products under this program.

On December 23, 2025, CMS, through its Center for Medicare and Medicaid Innovation, proposed two five-year pilot programs to implement a “reference pricing” regime for drugs paid for under Medicare for 25% of covered beneficiaries. The programs are referred to as the Global Benchmark for Efficient Drug Pricing Model for Medicare Part B drugs and the Guarding U.S. Medicare Against Rising Drug Costs for Medicare Part D drugs. Under the proposed pilot programs, a manufacturer would owe rebates to Medicare if prices for their drugs exceeded the prices paid by other economically comparable reference countries, defined in the proposed regulations as the Organization for Economic Co-operation and Development countries with a gross domestic product, or GDP, of $400 billion and a per capita GDP that is at least 60% of the U.S. per capita GDP (an initial list of 19 reference countries is included in the proposed rule). The pilot programs are proposed to go into effect beginning October 1, 2026.

Laws and regulations governing any international operations we may have may preclude us from developing, manufacturing and selling certain product candidates outside of the United States or adversely impact our ability to operate our business outside the United States. In addition, changes in and uncertainty surrounding U.S. trade policy could have a material adverse impact on our business, financial condition and results of operations.

The Trump administration, in 2025, initiated a series of tariff-related actions against U.S. trading partners. In February 2026, the U.S. Supreme Court held that the International Emergency Economic Powers Act of 1977 does not authorize the president to impose tariffs, invalidating both the “reciprocal” tariffs and certain country-specific tariffs previously imposed by executive orders. President Trump subsequently invoked Section 122 of the Trade Act of 1974, or Section 122, to impose a 10% tariff, which could be raised to 15%, on nearly all foreign imports. The tariffs imposed under Section 122 are temporary and valid for 150 days without congressional approval. On May 7, 2026, the U.S. Court of International Trade ruled that these tariffs were unlawful and issued a permanent injunction for certain named private party plaintiffs and the State of Washington;Washington. theThe U.S. government is expected to appealappealed to the U.S. Court of Appeals of the Federal Circuit, andand, additionalon litigationJune regarding11, 2026, the SectionFederal 122Circuit tariffsstayed isenforcement expected.of the lower court's permanent injunction pending further appeals. In addition, the U.S. Trade Representative is currently conducting two investigations under Section 301 of the Trade Act of 1974, which may also result in additional tariffs. In June 2026, in one such investigation, it proposed additional tariffs of 10% to 12.5% on products of 60 economies determined to have failed to impose and effectively enforce a prohibition on the importation of goods produced with forced labor, which were enacted by the U.S. Trade Representative in July 2026 at President Trump's direction. The second investigation into structural excess capacity and production in manufacturing sectors remains ongoing.

On April 2, 2026, President Trump issued a Proclamation invoking Section 232 of the Trade Expansion Act of 1962 to impose tariffs on imports of patented pharmaceuticals, biologics, and associated ingredients into the United States. Specifically, the Proclamation imposes a 100% tariff on pharmaceutical articles classified in certain 10-digit harmonized tariff schedule, or HTS, codes that are subject to a valid, unexpired U.S. patent and are listed in the FDA’s Approved Drug Products with Therapeutic Equivalence Evaluations, or the Orange Book, or are listed in the FDA’s Lists of Licensed Biological Products, or the Purple Book, unless a relevant exemption applies. The 100% tariff also applies to active pharmaceutical ingredients, or APIs, and key starting materials for such articles. For companies like ours that are not listed in the Annexes to the Proclamation (i.e., those that have not concluded qualifying onshoring plans and MFN pharmaceutical pricing agreements with the U.S. Government), these tariffs will be effective on September 29, 2026. Preferential tariff rates are provided for imports of covered pharmaceuticals from Japan, the EU, Korea, Switzerland, LichtensteinLiechtenstein and the UK. Certain categories of products are exempt from these tariffs, including, but not limited to, generic pharmaceuticals and biosimilars, specified U.S.-origin pharmaceutical products, and products classified under certain HTS codes listed in Annex IV of the Proclamation. Also likely to be exempt from the Section 232 tariffs are drugs and associated ingredients for all approved indications that are designated as orphan pursuant to the Orphan Drug Act; drugs for certain specific uses, including nuclear medicines; plasma-derived therapies; fertility treatments; cell and gene therapies; antibody drug conjugates; medical countermeasures related to chemical, biological, radiological, and nuclear threats; animal health; and other specialty pharmaceutical products to be later identified by the Secretary of Commerce.

There is also substantial uncertainty as to how regulatory reform measures being implemented by the Trump administration across the government will impact the FDA and other federal agencies with jurisdiction over our activities. For example, since taking office, President Trump has issued a number of executive orders that could have a significant impact on the manner in which the FDA conducts its operations and engages in regulatory and oversight activities. These include executive order 14192, “Unleashing Prosperity Through Deregulation,” January 31, 2025; executive order 14212, “Establishing the President’s Make America Healthy Again Commission,” February 13, 2025; and executive order 14219, “Ensuring Lawful Governance and Implementing the President’s ‘Department of Government Efficiency' Deregulatory Initiative,” February 21, 2025. If these or other orders or executive actions impose constraints on the FDA’s ability to engage in oversight and implementation activities in the normal course, our business may be negatively impacted.

As of MarchJune 31,30, 2026, we had 263289 full-time employees. As our development progresses, we expect to experience significant growth in the number of our employees and the scope of our operations, particularly in the areas of drug development, clinical, regulatory affairs and, if any product candidate we may develop receives marketing approval, sales, marketing, distribution and coverage and reimbursement capabilities. To manage our anticipated future growth, we must continue to implement and improve our managerial, operational and financial systems, expand our facilities and continue to recruit and train additional qualified personnel. Due to our limited financial resources and the limited experience of our management team in managing a company with such anticipated growth, we may not be able to effectively manage the expansion of our operations or recruit and train additional qualified personnel. The expansion of our operations may lead to significant costs and may divert our management and business development resources. Any inability to manage growth could delay the execution of our business plans or disrupt our operations.

Our executive officers and directors and their affiliates, in the aggregate, beneficially owned shares representing approximately 9.4%6.6% of our common stock as of MarchJune 31,30, 2026. As a result, if these stockholders were to choose to act together, they would be able to significantly influence all matters submitted to our stockholders for approval, as well as our management and affairs, even though some of these persons or entities may have interests different than yours. For example, these stockholders, if they choose to act together, could significantly influence the election of directors and approval of any merger, consolidation or sale of all or substantially all of our assets.

Sales of a substantial number of shares of our common stock in the public market, or the perception in the market that the holders of a large number of shares intend to sell shares, could reduce the market price of our common stock or impair our ability to raise capital through the sale of equity securities in the future. As of MayJuly 8,24, 2026, we had 165,313,796186,746,431 shares of common stock outstanding.

Z-basivarsenIn isJune being2026, evaluatedwe in the ACHIEVE trial, a global Phase 1/2 clinical trial designed to be registrational, and the HARMONIA trial, a global Phase 3 clinical trial designed to be confirmatory, which was initiated in March 2026. We have aligned with the FDA on the HARMONIA trial design and protocol. We have also reached ourcompleted enrollment target of 6071 participants in the registrational expansion cohort, or REC, of the ACHIEVE trial. We plan to allow any participants currently in screening to enroll if they meet all eligibility criteria. As a result, we expect to complete enrollment of more than 60 participants in the second quarter of 2026. We plan to announce data from the REC in the first quarter of 2027 to support a potential BLA submission to the FDA for U.S. Accelerated Approval early in the third quarter of 2027. We anticipate a potential U.S. launch of z-basivarsen in the first quarterhalf of 2028, assuming we receive favorable data from the REC, priority review is granted, and FDA approval is received on the anticipated timeline. We continue to pursue approval pathways outside of the United States for z-basivarsen.

We continue to explore additional applications for our proprietary FORCE platform, along with further iterations. To that end, we have identified two compounds, which we refer to as Conjugate 1 and Conjugate 2, utilizing a Fab conjugated to microtubule associated protein tautau, (MAPT)or MAPT, siRNA designed to downregulate expression of all MAPT isoforms. Conjugate 1 utilizes our FORCE platform with the same Fab as our other programs. Conjugate 2 utilizes a modified form of the FORCE TfR1-binding Fab that has been further optimized for enhanced central nervous system delivery and potential use in neurological indications. In preclinical studies, both conjugates achieved robust MAPT RNA knockdown (approximately 75% for Conjugate 2) in both mice and nonhuman primates, with widespread and consistent delivery across brain regions, including the deep brain. Subcutaneous administration in mice achieved an equivalent reduction in MAPT RNA as compared to intravenous administration in mice.

Since our inception, we have incurred significant operating losses. Our ability to generate any product revenue or product revenue sufficient to achieve profitability will depend on the successful development and eventual commercialization of one or more product candidates. For the threesix months ended MarchJune 31,30, 2026 and 2025, we reported net losses of $120.9$299.4 million and $115.4$226.2 million, respectively. As of MarchJune 31,30, 2026, we had an accumulated deficit of $1.5$1.7 billion.

We believe that our existing cash, cash equivalents and marketable securities as of June 30, 2026, as well as the approximately $405.0 in net proceeds from the July 2026 offering, will enable us to fund our operating expenses, debt service obligations and capital expenditure requirements into the firstsecond quarter of 2028.

The U.S. administration has announced or imposed multiple series of tariffs on U.S. trading partners, and there is uncertainty as to whether, when, or to what extent they may apply to our supply chain.partners. In response, several countries have threatened or imposed retaliatory measures, and multiple states have challenged these tariffs in court. While we have not experienced, and do not currently expect to experience, any significant direct impact from these tariffs or retaliatory measures, we could experience a negative impact on our costs of materials and production processes and supply chain disruptions, and the uncertainty surrounding the future of U.S. trade policy may itself negatively impact our supply chain operations and the costs of materials and production processes. Supply chain disruptions may impact the development, testing and clinical trials of our product candidates, and regulatory approval or commercial launch of any resulting product may be delayed or not obtained, which could significantly harm our business. The full extent of the future impact of these and other threatened measures remains uncertain. We continue to monitor these tariffs, retaliatory measures, and related litigation, and their possible effects on our business. See Part II, Item 1A. “Risk Factors—Risks related to regulatory approval and other regulatory and legal compliance matters” in this Quarterly Report for additional risks associated with current U.S. trade policy.

Comparison of the three months ended MarchJune 31,30, 2026 and 2025

The following table summarizes our results of operations for the three months ended MarchJune 31,30, 2026 and 2025:

The following table summarizes our research and development expenses for the three months ended MarchJune 31,30, 2026 and 2025:

Expenses related to z-rostudirsen increased in the three months ended MarchJune 31,30, 2026 compared to the three months ended MarchJune 31,30, 2025. This was attributable to higherincreased manufacturing activity in the firstsecond quarter of 2026 forof drug substance conjugationcomponents primarily for clinical supply for the long-term extension of the DELIVER trial and the anticipated commencement of the global confirmatory Phase 3 clinical trial of z-rostudirsenz-rostudirsen, FORZETTO, that commenced in the second quarter of 2026. Additionally, higher clinical costs were incurred in the firstsecond quarter of 2026 due to z-rostudirsenthe Phasecommencement 3of start-upthe costs.FORZETTO trial. Expenses related to z-basivarsen decreasedincreased in the three months ended MarchJune 31,30, 2026 compared to the three months ended MarchJune 31,30, 2025. This was primarily attributable to higherincreased manufacturing activity in the second quarter of 2026 of drug substance and components primarily for clinical supply for the registrational expansion cohort of the ACHIEVE trial and the global confirmatory Phase 3 clinical trial of z-basivarsen, HARMONIA, that commenced in the first quarter of 20252026. for process performance qualification batches of oligonucleotide payload and the timing of drug substance conjugation activities, partially offset byAdditionally, higher clinical trialcosts costswere incurred in the second quarter of 2026 due to the ongoingcompletion of enrollment of the registrational expansion cohort of the ACHIEVE trial andin the commencementsecond quarter of 2026 and increased enrollment in the HARMONIA trial in March 2026.trial.

The increase in platform and external research and development expenses in the three months ended MarchJune 31,30, 2026 compared to the three months ended MarchJune 31,30, 2025 was due to increased external research activity associated with our preclinical programs and product candidates, primarily DYNE-302 and DYNE-401.candidates. The increase in personnel-related expenses was primarily due to increasedthe headcountincrease of 39 employees in our research and development function of 37 employeesheadcount and higher stock-based compensation expense for awards granted to new hires and existing employees. The increase in facility-related and other expenses was primarily due to the increased costs of supporting a larger number of research and development personnel.

The following table summarizes our general and administrative expenses for the three months ended MarchJune 31,30, 2026 and 2025:

The increase in personnel-related and stock-based compensation expenses in the three months ended MarchJune 31,30, 2026 compared to the three months ended MarchJune 31,30, 2025 was due to increasedthe headcountincrease of 44 employees in our general and administrative function of 34 employees.headcount. Professional and consulting fees increased due to the higher consulting costs for the preparation activities for the potential launch of z-rostudirsen and the overall growth of the organization in the three months ended MarchJune 31,30, 2026. Facility-related and other expenses increased due to higher costs of supporting a larger number of general and administrative personnel in the three months ended MarchJune 31,30, 2026.

Interest income for the three months ended MarchJune 31,30, 2026 and 2025 was $8.8$7.8 million and $7.1$6.6 million, respectively, due to interest earned on invested cash balances. The increase in interest income was due to increased cash, cash equivalents and marketable securities balances in the three months ended MarchJune 31,30, 2026 compared to the three months ended MarchJune 31,30, 2025.

Interest expense for the three months ended MarchJune 31,30, 2026 was $4.2$4.6 million due to our entry into the Loan Agreement with Hercules in June 2025. Noand interest owed on our vendor financing arrangement. Interest expense was incurred infor the three months ended MarchJune 31,30, 2025.2025 was less than $0.1 million due to our Loan Agreement with Hercules.

Other incomeexpense, net, for the three months ended MarchJune 31,30, 2026 and 2025 was $0.1 million and $1.6 million, respectively, in each quarter due to realized foreign currency gains.losses.

Since our inception, we have incurred significant operating losses. We expect to incur significant expenses and operating losses for the foreseeable future as we support our continued research activities and development of our product candidates and platform. We have not yet commercialized any product candidates, and we do not expect to generate revenue from sales of any product candidates at least until 2027, if at all. To date, we have funded our operations primarily with proceeds from sales of equity securities and our borrowing under the Loan Agreement with Hercules. As of MarchJune 31,30, 2026 we had cash, cash equivalents and marketable securities of $972.2$898.5 million.

In November 2021, we entered into an Open Market Sale AgreementSM, or the Sales Agreement, with Jefferies LLC, or Jefferies. On March 5, 2024, we filed a universal shelf registration statement on Form S-3, or the 2024 Shelf Registration Statement, and included a prospectus relating to the Sales Agreement. Under the 2024 Shelf Registration Statement, we may offer and sell debt securities, common stock, preferred stock, units and/or warrants from time to time at an indeterminate aggregate offering price in one or more offerings. In November 2024, we filed a prospectus supplement relating to the Sales Agreement, pursuant to which, in accordance with the Sales Agreement, we may offer and sell shares of our common stock having an aggregate offering price of up to $300.0 million, which we refer to as our at-the-market offering program. Sales of common stock under the Sales Agreement through Jefferies may be made by any method that is deemed an “at-the-market” offering as defined in Rule 415(a)(4) under the Securities Act. During the threesix months ended MarchJune 31,30, 2026, we did not issue or sell any shares of common stock pursuant to the Sales Agreement.

In June 2025, we entered into the Loan Agreement with Hercules, in its capacity as administrative agent and collateral agent and as a lender, and certain other financial institutions that from time to time become parties to the Loan Agreement as lenders, which we refer to collectively as the Lenders. In December 2025, we entered into the First Amendment to the Loan Agreement with Hercules. In June 2026, we entered into the Second Amendment to the Loan Agreement with Hercules. The Loan Agreement, as amended by the First and the Second Amendment, provides for term loans in an aggregate principal amount of up to $275.0$400.0 million under multiple tranches, available as follows: (i) an initial term loan tranche funded on the closing date of the Loan Agreement in aggregate principal amount of $100.0 million; (ii) subject to the achievement of specified clinical, regulatory and commercial milestones, and after the borrowing of the second term loan tranche of $50.0 million in December 2025,2025 twoand third term loan tranche of $50.0 million in June 2026, three additional term loan tranches totaling up to $75.0$125.0 million; and (iii) subject to approval by the Lenders’ investment committee in their discretion, a final term loan tranche of up to $50.0$75.0 million. At MarchJune 31,30, 2026, the principal term loan balance was $150.0$200.0 million. Refer to Note 7, “Debt” in the accompanying notes to the condensed consolidated financial statements for a discussion of the Loan Agreement with Hercules.

During the threesix months ended MarchJune 31,30, 2026, operating activities used $144.9$275.2 million of cash, due to our net loss of $120.9$299.4 million and net cash used by changes in our operating assets and liabilities of $37.6$4.8 million, partially offset by non-cash charges of $13.6$29.0 million. Net cash used in changes in our operating assets and liabilities primarily consisted of a $32.8$23.4 million increase in prepaid expenses and other current assetsassets, andpartially offset by a $4.8$14.2 million decreaseincrease in accounts payable and other liabilities.liabilities and a $4.4 million decrease in other non-current assets. During the threesix months ended MarchJune 31,30, 2025, operating activities used $105.9$200.6 million of cash, due to our net loss of $115.4$226.2 million, partially offset by non-cash charges of $23.6 million and net cash usedprovided by changes in our operating assets and liabilities of $3.6 million, partially offset by non-cash charges of $13.1$2.0 million. Net cash usedprovided by changes in our operating assets and liabilities primarily consisted of a $8.6 million decrease in accounts payable and other liabilities and a $5.0$2.8 million decrease in prepaid expenses and other current assets.assets, partially offset by a $0.8 million decrease in accounts payable and other liabilities. Changes in our operating assets and liabilities during these periods were generally due to the growth of our business, increased clinical trial activity, increased manufacturing activities, advancement of our product candidates,candidates and the timing of vendor invoices and payments and annual bonus payments.

During the threesix months ended MarchJune 31,30, 2026, net cash used in investing activities was $2.4$7.2 million due to purchases of marketable securities of $64.3$107.1 million and purchases of property and equipment of $0.2$1.7 million, partially offset by maturities of marketable securities of $33.5$58.2 million and sales of marketable securities of $28.6$43.4 million. During the threesix months ended MarchJune 31,30, 2025, net cash provided by investing activities was $1.5$8.2 million due to maturities of marketable securities of $65.4$107.7 million and sales of marketable securities of $3.0$8.5 million, partially offset by purchases of marketable securities of $66.0$106.9 million and purchases of property and equipment of $1.0 million.

During the threesix months ended MarchJune 31,30, 2026, net cash provided by financing activities was $7.1$65.2 million, including $6.8$49.5 million in net proceeds from the third term loan tranche under our Loan Agreement with Hercules, $18.0 million in proceeds from our vendor financing arrangement that we entered into during the quarter and $1.3$2.0 million in proceeds received from stock option exercises. These cash inflows were partially offset by $0.6$3.9 million in repayments related to our vendor financing arrangement and the payment of $0.4 million of issuance costs from the follow-on public offering we completed in December 2025, pursuant to which we issued and sold 21,827,549 shares of our common stock and from which we received net proceeds of $377.7 million, after deducting underwriting discounts and commissions and offering expenses paid by us. During the threesix months ended MarchJune 31,30, 2025, net cash provided by financing activities was $141.2$242.0 million, consisting of $140.6 million in aggregate net proceeds from sales of our common stock under our at-the-market offering programprogram, $98.8 million in net proceeds from the initial term loan tranche under the Loan Agreement with Hercules and $0.6$2.6 million in net proceeds received from stock option exercises.

We believe that our existing cash, cash equivalents and marketable securities as of June 30, 2026, as well as the approximately $405.0 in net proceeds from the July 2026 offering, will enable us to fund our operating expenses, debt service obligations, and capital expenditure requirements into the firstsecond quarter of 2028. We have based this estimate on assumptions that may prove to be wrong, and we could exhaust our available capital resources sooner than we expect.

On January 15, 2025, we entered into a master manufacturing services agreement with a CMO which secures capacity at the CMO's manufacturing facilities for certain of our product candidates and components thereof. As of MarchJune 31,30, 2026, we have paid $27.7 million towards current assets and $31.2$26.9 million towards non-current assets under this agreement and pursuant to a mutually agreed rolling forecast we have committed to pay an additional $107.6$99.7 million in fees through MarchJune 2028. In specified termination circumstances, the agreement requires us to pay the CMO for services completed, the cost of the CMO's raw materials that cannot be repurposed and specified cancellation fees. This agreement formalizes and supersedes a letter agreement that we entered into with the CMO on July 18, 2024.

On October 31, 2025, we entered into another master manufacturing services agreement with a CMO which also secures capacity at the CMO's manufacturing facilities for certain of our product candidate components. The agreement obligates us to compensate the CMO for producing certain of our product candidate components pursuant to a mutually agreed rolling forecast, pursuant to which, as of MarchJune 31,30, 2026, we have committed to pay an additional $52.7$59.8 million in fees through SeptemberDecember 2027. In specified termination circumstances, the agreement requires us to pay the CMO for services completed, the cost of the CMO's raw materials that cannot be repurposed, capital equipment and certain manufacturing activities previously committed to.

Refer to Note 2, "Summary of Significant Accounting Policies" in the accompanying notes to the condensed consolidated financial statements for a discussion of significant accounting policies. There are no recently issued accounting pronouncements that have not yet been adopted that are expected to have a material impact on the Company’s financial statements as of MarchJune 31,30, 2026.