Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations.

You should read the following discussion and analysis of our financial condition and consolidated results of operations together with our consolidated financial statements and related notes appearing elsewhere in this Annual Report on Form 10-K. Some of the information contained in this discussion and analysis or set forth elsewhere in this Annual Report on Form 10-K, including information with respect to our plans and strategy for our business and related financing, includes forward-looking statements that involve risks and uncertainties. You should carefully read the sections entitled “Risk Factors” and “Special Note Regarding Forward-Looking Statements” to gain an understanding of the important factors that could cause actual results to differ materially from our forward-looking statements.

Overview

We are a late-stage clinical company dedicated to addressing the underlying causes of severe diseases by upregulating protein expression with RNA-based medicines. Using our proprietary TANGO (Targeted Augmentation of Nuclear Gene Output) approach, we are developing antisense oligonucleotides (“ASOs”) to selectively restore protein levels.

Our first investigational new medicine in development, zorevunersen (STK-001), is a potential disease modifying medicine that is in late-stage clinical testing for the treatment of Dravet syndrome. Dravet syndrome is characterized by frequent, prolonged and refractory seizures beginning within the first year of life. The disease is classified as a developmental and epileptic encephalopathy (DEE) due to the developmental delays and cognitive impairment associated with it. Dravet syndrome is one of many diseases caused by a haploinsufficiency, in which a loss of approximately 50% of normal protein levels leads to disease.

Following discussions with the U.S. Food and Drug Administration (“FDA”), European Medicines Agency (“EMA”), and Japan’s Pharmaceuticals and Medical Devices Agency (“PMDA”), a global Phase 3 study, EMPEROR, was initiated in May 2025, with the first patient dosed in August 2025. This trial follows the completion of two open-label Phase 1/2a studies, MONARCH in the United States and ADMIRAL in the United Kingdom, and further evaluates the efficacy and safety of zorevunersen in children and adolescents ages 2 to up to 18 with Dravet syndrome.

In addition to the MONARCH and ADMIRAL studies, we continue to run open-label extension (“OLE”) studies in patients who completed the Phase 1/2a studies and met study entry criteria. The four studies have shown substantial and durable reductions in convulsive seizure frequency when administered on top of standard of care anti-seizure medicines. In the Phase 1/2a studies, 85% of patients were taking at least three and 54% were taking at least four medicines to control seizures. Half the patients in the studies were taking concomitant fenfluramine. Ongoing treatment has led to continuous improvements in cognition and behavior through three years. Additional improvements were indicated within the first nine months of treatment among patients in the Phase 1/2a study. These improvements were observed across multiple domains of the Vineland-3 (Vineland Adaptive Behavior Scale, Third Edition), a standardized assessment of behavioral outcomes that is a key secondary endpoint for the Phase 3 study. Zorevunersen has been generally well tolerated across the studies.

In addition to our Dravet program, we are also pursuing treatment for a second haploinsufficient disease, autosomal dominant optic atrophy (“ADOA”), the most common inherited optic nerve disorder for which there are currently no approved treatments. STK-002 is our clinical candidate for the treatment of ADOA. STK-002 is designed to upregulate OPA1 protein expression by leveraging the non-mutant (wild-type) copy of the OPA1 gene to restore OPA1 protein expression with the aim to stop or slow vision loss in patients with ADOA. In a non-human primate (NHP) model of ADOA conducted in collaboration with UC Davis, treatment with STK-002 was well tolerated and helped protect, and possibly improve, eye health. The data suggest that STK-002 may help preserve the function of important vision-related nerve cells, which could potentially improve or maintain vision. We received authorization in the UK to proceed with a Phase 1 open-label study (OSPREY) of children and adults ages 6 to 55 who have an established diagnosis of ADOA and have evidence of a genetic mutation in the OPA1 gene. In February 2026, we dosed the first patient with STK-002 in the OSPREY Phase 1 study for the treatment of ADOA.

In terms of our liquidity and capital resources, in May 2022, we filed a universal Shelf Registration statement on Form S-3 (the “2022 Registration Statement”) with the SEC. The 2022 Registration Statement was declared effective by the SEC on May 31, 2022, and contained two prospectuses: a base prospectus, which covered the offering, issuance and sale by us of up to a maximum aggregate offering price of $400.0 million of our common stock, preferred stock, debt securities, warrants to purchase common stock, preferred stock or debt securities, subscription rights to purchase common stock, preferred stock or debt securities and/or units consisting of some or all of these securities; and a sales agreement prospectus covering the offering, issuance and sale by us of up to a maximum aggregate offering price of $150.0 million of common stock that may be issued and sold under a Controlled Equity Offering Sales Agreement (the “Sales Agreement”).

On April 2, 2024, we completed an underwritten public offering, pursuant to the 2022 Registration Statement, of 5,555,557 shares of common stock at a public offering price of $13.50 per share and issued pre-funded warrants to purchase

3,703,730 shares of common stock at a public offering price of $13.499 per share subject to an exercise price equal to $0.0001. The common stock and pre-funded warrants sold resulted in net proceeds of approximately $119.9 million after deducting underwriting discounts, commissions and offering costs. No pre-funded warrants have been exercised as of December 31, 2025.

In October 2024, we filed an automatic universal Shelf Registration statement on Form S-3 (the “2024 Registration Statement”) with the SEC. Following the filing of our Annual Report on Form 10-K for the year ended December 31, 2024 in March 2025, the 2024 Registration Statement became ineffective.

In July 2025, we filed a universal Shelf Registration Statement on Form S-3 (the “2025 Registration Statement”) with the SEC. The 2025 Registration Statement was declared effective by the SEC on July 11, 2025, and contains two prospectuses: a base prospectus, which covers the offering, issuance and sale by us of up to a maximum aggregate offering price of $400.0 million of our common stock, preferred stock, debt securities, warrants to purchase common stock, preferred stock or debt securities, subscription rights to purchase common stock, preferred stock or debt securities and/or units consisting of some or all of these securities; and a sales agreement prospectus covering the offering, issuance and sale by us of up to a maximum aggregate offering price of $150.0 million of common stock that may be issued and sold under the Sales Agreement. The specific terms of any securities to be offered pursuant to the base prospectus will be specified in a prospectus supplement to the base prospectus.

As of December 31, 2025, we had issued approximately 7.0 million shares of common stock pursuant to the Sales Agreement for net proceeds of $61.0 million pursuant to the 2022 Registration Statement. As of December 31, 2025, we had issued approximately 3.2 million shares of common stock pursuant to the 2025 Registration Statement for net proceeds of $87.8 million. We may terminate this at-the-market program under the Sales Agreement at any time, pursuant to its terms.

As of December 31, 2025 and December 31, 2024 we had $390.9 million and $246.7 million, respectively, in cash, cash equivalents and marketable securities.

Since inception, we have had operating losses, the majority of which are attributable to research and development activities. Our net losses were $6.9 million and $89.0 million for the years ended December 31, 2025 and 2024, respectively. As of December 31, 2025, we had an accumulated deficit of $497.7 million.

Our primary use of cash is to fund operating expenses, which consist primarily of research and development activities, including medical affairs, as well as sales, general and administrative expenses, including commercial operations. Cash used to fund operating expenses is impacted by the timing of when we pay these expenses, as reflected in the change in our outstanding accounts payable and accrued expenses. We expect to continue to incur net losses for the foreseeable future, and we expect our research and development expenses, sales, general and administrative expenses will continue to increase. In particular, we expect our expenses and losses to increase as we continue our development of, and seek regulatory approvals for, our product candidates, and begin to commercialize any approved products. Our net losses may fluctuate significantly from quarter-to-quarter and year-to-year, depending on the timing of our clinical trials and our expenditures on other research and development activities.

Based upon our current operating plan, we believe that our cash, cash equivalents, and marketable securities of approximately $390.9 million as of December 31, 2025, will fund operations into 2028. To date, we have not had any products approved for sale and have not generated any product sales. We do not expect to generate any revenues from product sales unless and until we successfully complete development and obtain regulatory approval for one or more of our product candidates. If we obtain regulatory approval for any of our product candidates, we expect to incur significant commercialization expenses related to product sales, marketing, manufacturing and distribution. As a result, until such time, if ever, as we can generate substantial product revenue, we expect to finance our cash needs through equity offerings, debt financings or other capital sources, including potentially collaborations, licenses and other similar arrangements. However, we may be unable to raise additional funds or enter into such other arrangements when needed on favorable terms or at all. Any failure to raise capital as and when needed could have a negative impact on our financial condition and on our ability to pursue our business plans and strategies. If we are unable to raise capital, we will need to delay, reduce or terminate planned activities to reduce costs.

Financial Operations Overview

Revenue

We are comprised of one reportable segment and as of December 31, 2025 and 2024, have not generated any product revenue since inception, as we do not yet have approved products for sale. If we are able to successfully develop, receive regulatory approval for and commercialize any of our current or future product candidates alone or in collaboration with third parties, we may generate revenue from the sales of these product candidates.

In January 2022, we entered into a License and Collaboration Agreement (the “Acadia Agreement”) with Acadia Pharmaceuticals Inc. (“Acadia”) for the discovery, development and commercialization of novel RNA-based medicines for the treatment of severe and rare genetic neurodevelopmental diseases of the central nervous system. The Acadia Agreement focused on the targets SYNGAP1, MECP2 (Rett syndrome), and an undisclosed neurodevelopmental target of mutual interest. In connection with each target, we agreed to collaborate with Acadia to identify potential treatments for further development and commercialization as licensed products. With respect to SYNGAP1, we agreed with Acadia to co-develop and co-commercialize licensed products for such target globally, and in connection therewith we granted to Acadia worldwide, co-exclusive (with us) licenses for such licensed products. With respect to SYNGAP1, we agreed with Acadia to co-develop and co-commercialize licensed products for such target globally, and in connection therewith we granted to Acadia worldwide, co-exclusive (with us) licenses for such licensed products. With respect to MECP2 and the neurodevelopmental target, we granted Acadia worldwide, exclusive licenses to develop and commercialize licensed products for such targets. Effective as of September 3, 2025, Acadia terminated the MECP2 and the undisclosed neurodevelopmental programs under the Acadia Agreement (the “Discontinued Acadia Programs”) and rights to these targets returned to us. The collaboration with Acadia with respect to SYNGAP1 remains ongoing.

Pursuant to the terms of the Acadia Agreement, we received an upfront payment of $60.0 million from Acadia. Acadia agreed to fund the research for the Discontinued Acadia Programs, and we will equally fund with Acadia the research to identify potential licensed products for SYNGAP1. We are eligible to receive up to $245.0 million in potential total milestone payments based upon the achievement of certain development, regulatory, first commercial sales and sales milestone events for the SYNGAP1 program, assuming each milestone were achieved at least once. For SYNGAP1 licensed products that we are co-developing and co-commercializing, we will be responsible for 50% of the development and commercialization costs and will receive 50% of the profits from global commercialization. We are provided a co-development and co-commercialization opt out option relating to the SYNGAP1 target indication at our discretion. Such opt-out would reduce development and commercialization milestones but would provide us with royalties on an escalating basis attributable to net sales milestones. As a result of the termination of the Discontinued Acadia Programs, we are no longer eligible to receive the milestones for those programs of up to $662.5 million or any royalties related thereto.

For the year ended, December 31, 2025, we recognized revenue related to the Acadia collaboration of $16.1 million and for the year ended, December 31, 2024, we recognized revenue related to the Acadia collaboration of $36.6 million.

On February 14, 2025, we entered into a License and Collaboration Agreement (the “Biogen Agreement”) with Biogen International GmbH (“Biogen”) for the joint development and commercialization of zorevunersen and other compounds targeting the SCN1A gene (the “Licensed Product”). Under the terms of the Biogen Agreement, we granted Biogen an exclusive, royalty-bearing license to develop, manufacture, and export licensed products in all territories outside the U.S., Canada, and Mexico (the “Biogen Territory”). In addition, Biogen has the option to exercise an exclusive, royalty-bearing, sublicensable and transferable license for certain future follow-on ASOs directed to SCN1A controlled by us. Under the Biogen Agreement, the parties are jointly developing zorevunersen, and we are leading global development. We and Biogen share global development costs based on an agreed budget. We are responsible for 70% of these development costs and Biogen is responsible for the remaining 30% of these development costs.

In connection with the closing of this transaction in February 2025, we received an upfront payment of $165.0 million and are eligible to receive development and commercial milestone payments that could total up to approximately $50.0 million and $335.0 million, respectively, if all the specified milestones set forth in this collaboration are achieved. In addition, we are eligible to receive tiered, double-digit royalties ranging from the low double-digit to high teen percentages of future net sales on the licensed products. As of December 31, 2025, no milestones have been met. Royalties payable under the Biogen Agreement are subject to standard royalty reductions.

For the year ended, December 31, 2025, we recognized revenue related to the Biogen collaboration of $168.3 million; there was no revenue prior to 2025 related to the Biogen collaboration.

See Note 8—License and Collaboration Agreements of the notes to our consolidated financial statements included elsewhere in this Annual Report on Form 10-K.

Research and development

Research and development expenses consist primarily of costs incurred for the development of our discovery work and preclinical programs, which include:

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personnel costs, which include salaries, benefits and stock-based compensation expense;

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expenses incurred under agreements with consultants, third-party contract organizations that conduct research and development activities on our behalf, costs related to production of preclinical material and laboratory and vendor expenses related to the execution of preclinical studies;

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scientific consulting, collaboration and licensing fees;

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laboratory equipment and supplies; and

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facilities costs, depreciation and other expenses related to internal research and development activities.

We use our personnel and infrastructure resources across multiple research and development programs directed toward identifying and developing product candidates. Our direct research and development expenses are tracked on a program-by-program basis from the point a program becomes a clinical candidate for us and consists primarily of external costs, such as fees paid to consultants, central laboratories and contractors in connection with our preclinical activities. We do not allocate employee costs, costs associated with our technology or facility expenses, including depreciation or other indirect costs, to specific programs because these costs are currently deployed across multiple product development programs and, as such, are not separately classified. We use internal resources to manage our development activities and our employees work across multiple development programs and, therefore, we do not track their costs by program.

The table below summarizes our research and development expenses incurred by development program (in thousands):

Year ended December 31,

Total research and development expenses $ 137,922 $ 89,133

We expense all research and development costs in the periods in which they are incurred. Costs for certain development activities are recognized based on an evaluation of the progress to completion of specific tasks using information and data provided to us by our vendors and third-party service providers.

We expect that our expenses will increase substantially in connection with our planned discovery work, preclinical and clinical development activities in the near term and our planned clinical trials in the future. At this time, we cannot reasonably estimate the costs for completing the preclinical and clinical development of any of our other product candidates. We expect our research and development expenses to increase substantially for the foreseeable future as we continue to invest in research and development activities related to developing our product candidates, including investments in manufacturing, as our programs advance into later stages of development and we conduct clinical trials. The process of conducting the necessary clinical research to obtain regulatory approval is costly and time-consuming, and the successful development of our product candidates is highly uncertain. As a result, we are unable to determine the duration and completion costs of our research and development projects or when and to what extent we will generate revenue from the commercialization and sale of any of our product candidates.

Because of the numerous risks and uncertainties associated with product development, we cannot determine with certainty the duration and completion costs of the current or future preclinical studies and clinical trials or if, when, or to what extent we will generate revenues from the commercialization and sale of our product candidates. We may never succeed in achieving regulatory approval for our product candidates. The duration, costs and timing of preclinical studies and clinical trials and development of our product candidates will depend on a variety of factors, including:

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successful completion of preclinical studies and investigational new drug-enabling studies;

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successful enrollment in, and completion of, clinical trials;

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receipt of regulatory approvals from applicable regulatory authorities;

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furthering our commercial manufacturing capabilities and arrangements with third-party manufacturers;

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obtaining and maintaining patent and trade secret protection and non-patent exclusivity;

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launching commercial sales of our product candidates, if and when approved, whether alone or in collaboration with others;

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acceptance of our product candidates, if and when approved, by patients, the medical community and third-party payors;

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effectively competing with other therapies and treatment options;

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a continued acceptable safety profile following approval;

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enforcing and defending intellectual property and proprietary rights and claims; and

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achieving desirable medicinal properties for the intended indications.

A change in the outcome of any of these factors could mean a significant change in the costs and timing associated with the development of our current and future preclinical and clinical product candidates. For example, if the FDA, or another regulatory authority were to require us to conduct clinical trials beyond those that we currently anticipate will be required for the completion of clinical development, or if we experience significant delays in execution of or enrollment in any of our preclinical studies or clinical trials, we could be required to expend significant additional financial resources and time on the completion of preclinical and clinical development. We expect our research and development expenses to increase for the foreseeable future as we continue the development of product candidates.

Sales, general and administrative expenses

Sales, general and administrative expenses consist primarily of personnel costs, costs related to maintenance and filing of intellectual property, expenses for outside professional services, including legal, human resources, information technology, audit and accounting services, and facilities and other expenses. Personnel costs consist of salaries, benefits and stock-based compensation expense. We expect our sales, general and administrative expenses to increase over the next several years to support our continued research and development activities, manufacturing activities, increased costs of operating as a public company and the potential commercialization of our product candidates. These increases are anticipated to include increased costs related to the hiring of additional personnel, developing commercial infrastructure, fees to outside consultants, lawyers and accountants, and costs associated with being a public company such as expenses related to services associated with maintaining compliance with Nasdaq listing rules and SEC requirements, insurance and investor relations costs.

Other income (expense)

Our other income (expense), net includes (i) interest income earned on cash reserves in our operating money market fund, investment accounts and on our marketable securities investments and (ii) other items of income (expense), net.

Results of Operations for the Years Ended December 31, 2025 and 2024

The following table sets forth our results of operations (in thousands):

Year ended December 31,

Consolidated statements of operations

Operating expenses:

Other income (expense):

Other income (expense), net (51 ) (247 )

Revenue

Revenue for the year ended December 31, 2025 was $184.4 million compared to $36.6 million for the year ended December 31, 2024, an increase of $147.8 million. Revenue is generated from satisfying contractual obligations of the collaboration and licensing agreements with Acadia and Biogen. The increase of $147.8 million is primarily driven by revenue of $150.8 million related to the IP license performance obligation and $17.5 million for global development activities as part of the Biogen Agreement offset by a decrease in revenue related to the Acadia Agreement.

Research and development expenses

Research and development expenses were $137.9 million for the year ended December 31, 2025 as compared to $89.1 million for the year ended December 31, 2024, an increase of $48.8 million. The table below summarizes our research and development expenses (in thousands):

Year Ended December 31,

Facilities and other research and development expenses 11,132 12,070

Total research and development expenses $ 137,922 $ 89,133

The increase in research and development expenses was driven primarily by a $33.8 million increase in expenses related to our zorevunersen program, which consisted of third‐party services and scientific consulting fees, $13.8 million increase in personnel‐related costs, a $1.8 million increase in external third‐party expenses related to non–program-specific expenses and $1.1 million in expenses related to SYNGAP1 and MECP2, both of which consisted of third‐party services and scientific consulting fees. These increases were partially offset by a $0.7 million decrease in expenses related to our ADOA program and a $1.0 million decrease in facilities and other non–program-related expenses.

Sales, general and administrative expenses

Sales, general and administrative expenses were $67.1 million for the year ended December 31, 2025 as compared to $48.8 million for the year ended December 31, 2024, an increase of $18.3 million.

The increases in sales, general and administrative expenses was primarily attributable to an increase of $7.4 million in personnel‐related costs, including increases in stock-based compensation expense, from increases in headcount and options awarded and an increase of $10.9 million in third-party services to support our in-house personnel in various aspects of developing and supporting the business including commercialization efforts, human resources, information technology, audit, tax, public relations, communications and other sales, general and administrative activities.

Other income (expense)

Our other income (expense), net includes (i) interest income earned on cash reserves in our operating, money market fund, investment accounts and on our marketable securities investments and (ii) other items of income (expense), net.

Liquidity and Capital Resources

Since our inception through December 31, 2025, our operations have been financed by net proceeds of $926.6 million from the sale of convertible notes payable and our convertible preferred stock, our initial public offering, follow-on offering, proceeds from the controlled equity offering sales agreements and the upfront payments from Acadia and Biogen. As of December 31, 2025, we had $390.9 million in cash, cash equivalents and marketable securities. Cash in excess of immediate requirements is invested in accordance with our investment policy, primarily with a view to liquidity and capital preservation.

We have incurred losses since our inception in June 2014 and, as of December 31, 2025 and 2024, we had accumulated deficits of $497.7 million and $490.8 million, respectively.

Our product candidates may never achieve commercialization and we anticipate that we will continue to incur losses for the foreseeable future. We expect that our research and development expenses, sales, general and administrative expenses, and capital expenditures will continue to increase. As a result, until such time, if ever, as we can generate substantial product revenue, we expect to finance our cash needs through a combination of equity offerings, debt financings and other capital sources, including potentially collaborations, licenses and other similar arrangements. Our primary uses of capital are, and we expect will continue to be, compensation and related expenses, third-party clinical research and development services, costs relating to the build-out of our headquarters and manufacturing facility, license payments or milestone obligations that may arise, laboratory and related supplies, clinical costs, manufacturing costs, legal and other regulatory expenses and general overhead costs.

Based upon our current operating plan, we believe that our cash, cash equivalents, and marketable securities of approximately $390.9 million as of December 31, 2025, will fund operations into 2028. We have based this estimate on assumptions that may prove to be wrong, and we could utilize our available capital resources sooner than we currently expect. We will continue to require additional financing to advance our current product candidates through clinical development, to develop, acquire or in-license other potential product candidates and to fund operations for the foreseeable future. We will continue to seek funds through equity offerings, debt financings or other capital sources, including potentially collaborations, licenses and other similar arrangements. However, we may be unable to raise additional funds or enter into such other arrangements when needed on favorable terms or at all. Our ability to raise additional funds may be adversely impacted by potential worsening global macroeconomic conditions, including inflation, changing interest rates and instability in the global banking system, tariffs, and disruptions to and volatility in the credit and financial markets in the United States and worldwide. If we do raise additional capital through public or private equity offerings, the ownership interest of our existing stockholders will be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect our stockholders’ rights. If we raise additional capital through debt financing, we may be subject to covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends. Any failure to raise capital as and when needed could have a negative impact on our financial condition and on our ability to pursue our business plans and strategies. If we are unable to raise capital, we will need to delay, reduce or terminate planned activities to reduce costs.

Because of the numerous risks and uncertainties associated with research, development and commercialization of pharmaceutical products, we are unable to estimate the exact amount of our operating capital requirements. Our future funding requirements will depend on many factors, including, but not limited to:

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the scope, progress, results and costs of researching and developing our lead product candidates or any future product candidates, and conducting nonclinical studies and clinical trials;

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the timing of, and the costs involved in, obtaining regulatory approvals or clearances for our lead product candidates or any future product candidates;

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the number and characteristics of any additional product candidates we develop or acquire;

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the timing of any cash milestone payments if we successfully achieve certain predetermined milestones;

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the cost of manufacturing our lead product candidates or any future product candidates and any products we successfully commercialize, including costs associated with building-out our manufacturing capabilities;

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our ability to establish and maintain strategic collaborations, licensing or other arrangements and the financial terms of any such agreements that we may enter into;

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the expenses needed to attract and retain skilled personnel;

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the costs associated with being a public company; and

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the timing, receipt and amount of sales of any future approved or cleared products, if any.

Further, our operating plans may change, and we may need additional funds to meet operational needs and capital requirements for clinical trials and other research and development activities. We currently have no credit facility or committed sources of capital. Because of the numerous risks and uncertainties associated with the development and commercialization of our product candidates, we are unable to estimate the amounts of increased capital outlays and operating expenditures associated with our current and anticipated product development programs.

Cash flows

The following table summarizes our cash flows (in thousands):

Year ended December 31,

Net cash provided by (used in):

Operating activities

During the year ended December 31, 2025, cash provided by operating activities was $45.6 million. This was primarily attributable to non-cash charges of $36.1 million for stock-based compensation, depreciation, amortization and accretion of marketable securities, and reduction in the carrying amount of right of use assets, a net change of $16.3 million in our net operating assets and liabilities which includes monies received related to the Biogen collaboration, offset by a net loss of $6.9 million.

During the year ended December 31, 2024, cash used in operating activities was $86.9 million. This was primarily attributable to a net loss of $89.0 million and by a net change of $28.1 million in our net operating assets and liabilities, offset by non-cash charges of $30.3 million for stock-based compensation, depreciation, amortization and accretion of marketable securities, and reduction in the carrying amount of right of use assets.

Investing activities

Our investing activities during the year ended December 31, 2025 consisted primarily of $322.7 million of purchases of marketable securities and $0.7 million of purchases of property plant and equipment offset by $136.6 million from the sales of marketable securities.

Our investing activities during the year ended December 31, 2024 consisted primarily of $167.3 million of purchases of marketable securities offset by $60.0 million from the sales of marketable securities.

Financing activities

Our financing activities during year ended December 31, 2025 consisted of $8.6 million from the exercise of stock options, $1.0 million in proceeds from our Employee Stock Purchase Plan and $87.8 million of net proceeds from the Sales Agreement.

Our financing activities during year ended December 31, 2024 consisted of $119.9 million of net proceeds from the follow-on offering, $1.7 million from the exercise of stock options, $0.5 million in proceeds from our Employee Stock Purchase Plan and $9.0 million of net proceeds from the Sales Agreement.

Contractual Obligations and Commitments

The following table summarizes our contractual obligations as of December 31, 2025 and the effects that such obligations are expected to have on our liquidity and cash flows in future periods (in thousands):

Payments Due by Period

Total Less Than1 Year 1 to 3Years 4 to 5Years More than5 Years

In August 2018, we entered into an agreement to lease approximately 23,000 square feet of space for a term of three years. Lease terms are triple net lease commencing at $0.9 million per year, then with 3% annual base rent increases plus operating expenses, real estate taxes, utilities and janitorial fees. The lease commencement date was December 10, 2018.

In September 2021, we entered into an agreement to extend the initial term of the 23,000 square foot lease for a period of three years. In addition, this agreement provides for the lease of an additional 15,000 square feet of rentable space beginning on April 1, 2022. Initial monthly lease payments are approximately $0.1 million with respect to the 23,000 square feet space, and $0.1 million with respect to the 15,000 square feet space, and in each case subject to annual rent escalations.

In December 2023, we entered into an agreement to extend the term of the 38,000 square foot lease for a period of two years commencing on January 1, 2025 and ending on December 31, 2026. In December 2023, we recognized a right-of-use asset and operating lease liability of $4.1 million.

In December 2018, we entered into an agreement to lease 2,485 square feet of space for a term of three years. The lease includes one renewal option for an additional two years. Lease terms commence at $0.2 million per year, with 2.5% annual base rent increases plus operating expenses, real estate taxes, utilities and janitorial fees. We occupied this space in May 2019.

In June 2021, we amended the agreement to extend the initial term of the 2,485 square foot lease for a period of three years ending April 30, 2025. In addition, the amendment provided for the lease of an additional 2,357 square feet of rentable space beginning on July 6, 2021 and ending on April 30, 2025. The amended lease provides us with the option to extend the term of the lease for an additional two years with a base annual rent increase of 3%. In March 2025, we further amended this lease to extend the term from April 30, 2025 to June 30, 2025.

In January 2025, we entered into an agreement to lease 7,581 square feet of space for an initial term of three years and three months. The lease includes two renewal options for an additional three years each. Lease terms commence at $0.7 million per annum, with 2% annual base rent increases plus operating expenses, real estate taxes, and utilities. The lease commencement date was July 8, 2025. In July 2025, we recognized a right-of-use asset and operating lease liability of $1.8 million. In September 2025, we entered into a sublease agreement for the 7,581 square feet of space for a term equal to the initial term of the original lease. Sublease terms commence at $0.4 million per annum with 2% annual rent increases. As a result of this sublease, we recognized a right-of-use asset impairment of $0.7 million.

In January 21, 2026, we entered into a new lease for our corporate headquarters and laboratory space with NWALP PHOP Property Owner LLC, located at 245 Fifth Avenue, Waltham, Massachusetts (the “Lease Agreement”), in order to expand our office and laboratory space. The Lease Agreement premises include approximately 98,500 square feet. The Lease Agreement will expire on March 31, 2038, and includes two options to further extend the Lease for an additional five years at the then-prevailing market rate. The aggregate estimated base rent payments due over the term of the Lease Agreement is approximately $85.5 million. We paid a security deposit of $3.0 million in the form of an irrevocable standby letter of credit, which may be reduced over time in accordance with the terms of the Lease Agreement. See “Note 14—Subsequent Events."

Commitments

Our commitments primarily consist of obligations under our agreement with the University of Southampton. As of December 31, 2025, we were unable to estimate the timing or likelihood of achieving the milestones or making future product sales. For additional information regarding our agreements, see “Business—License and research agreements.”

Additionally, we have entered into agreements with third-party contract manufacturers for the manufacture and processing of certain of our product candidates for preclinical testing purposes, and we have entered and will enter into other contracts in the normal course of business with contract research organizations for clinical trials and other vendors for other services and products for operating purposes. These agreements generally provide for termination or cancellation, other than for costs already incurred.

Off-Balance Sheet Arrangements

During the periods presented, we did not have, nor do we currently have, any off-balance sheet arrangements as defined under SEC rules.

Critical Accounting Policies and Significant Judgments and Estimates

Our management’s discussion and analysis of our financial condition and results of operations is based on our consolidated financial statements, which have been prepared in accordance with generally accepted accounting principles (“GAAP”). The preparation of these consolidated financial statements requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the

consolidated financial statements, as well as the reported expenses incurred during the reporting periods. Our estimates are based on our historical experience and on various other factors that we believe are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying value of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions. We believe that the accounting policies discussed below are critical to understanding our historical and future performance, as these policies relate to the more significant areas involving management’s judgments and estimates.

While our significant accounting policies are more fully described in Note 2 to our consolidated financial statements appearing elsewhere in this Annual Report on Form 10-K, we believe that the following accounting policies are the most critical in order to fully understand and evaluate our financial condition and results of operations.

Revenue Recognition

For revenue arrangements accounted for under ASC 606, we recognize revenue when a customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine the appropriate amount of revenue to be recognized for arrangements determined to be within the scope of ASC 606, we perform the following five steps: (i) identification of the contract; (ii) determination of whether the promised goods or services are performance obligations; (iii) measurement of the transaction price, including evaluating the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations; and (v) recognition of revenue when (or as) we satisfy each performance obligation. We apply the five-step model to all contracts, including transactions with collaborators or partners, if they are a transaction with a customer.

Performance obligations are promises to transfer distinct goods or services to the customer. Promised goods or services are considered distinct when (i) the customer can benefit from the good or service on its own or together with other readily available resources and (ii) the promised good or service is separately identifiable from other promises in the contract. In assessing whether promised goods or services are distinct, we consider factors such as the stage of development of the underlying intellectual property, the capabilities of the customer to develop the intellectual property on their own, or whether the required expertise is readily available.

We estimate the transaction price based on the amount expected to be received for transferring the promised goods or services in the contract. The consideration may include both fixed consideration and variable consideration. At the inception of an arrangement that includes variable consideration and at each reporting period, we evaluate the amount of potential payment and the likelihood that the payments will be received. We utilize either the most likely amount method or expected amount method to estimate the amount to be received based on which method better predicts the amount expected to be received. If it is probable that a significant reversal of cumulative revenue would not occur, the variable consideration is included in the transaction price. We will assess our revenue generating arrangements in order to determine whether a significant financing component exists and conclude that a significant financing component does not exist in any of its arrangements if: (a) the promised consideration approximates the cash selling price of the promised goods and services or any significant difference is due to factors other than financing; and (b) timing of payment approximates the transfer of goods and services and performance is over a relatively short period of time within the context of the entire term of the contract.

Contracts may include pre-commercial milestone payments. At contract inception and at each reporting period, we assess whether achievement of the milestone was most likely and whether it is probable that a significant reversal in the amount of cumulative revenue recognized would not occur. If it is probable that a significant reversal of cumulative revenue would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within our control or the customer’s control are constrained and not included in the transaction price. At the end of each subsequent reporting period, we re-evaluate the probability of achievement of such milestones and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenues and earnings in the period of adjustment.

For arrangements that may include sales-based royalties, including milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties relate, we recognize revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). To date, we have not recognized any royalty revenue resulting from any of the Company’s collaboration arrangements.

We allocate the transaction price based on the estimated standalone selling price of the underlying performance obligations or in the case of certain variable consideration to one or more performance obligations. We must develop assumptions that require judgment to determine the stand-alone selling price for each performance obligation identified in the contract. We utilize a range of key assumptions to determine the stand-alone selling price, which may include prices observed in comparable market transactions, pricing considered in negotiating the transaction, the estimated costs, plus a reasonable margin, forecasted revenue, development timelines, reimbursement rates for personnel costs, discount rates and probabilities of success in achieving various pre-commercial and commercial milestones, to complete the respective performance obligation. Certain variable consideration is allocated specifically to one or more performance obligations in a contract when

the terms of the variable consideration relate to the satisfaction of the performance obligation and the resulting amounts allocated to each performance obligation are consistent with the amounts we would expect to receive for each performance obligation.

For performance obligations consisting of licenses, research and development activities, and other promises, we utilize judgment to assess the nature of the performance obligation to determine whether the performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. We evaluate the measure of progress each reporting period and, if necessary, adjust the measure of performance and related revenue recognition. If the license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, we will recognize revenue when the license is transferred to the customer and the customer is able to use and benefit from the license. Upfront payments and fees are recorded as deferred revenue upon receipt or when due until we perform our obligations under these arrangements. Amounts are recorded as accounts receivable when the right to consideration is unconditional, including unbilled amounts.

Payment terms and conditions vary by contract type, although terms typically require payment within 30 to 60 days. In instances where the timing of revenue recognition differs from that of invoicing, we have determined that our contracts generally do not include a significant financing component. The primary purpose of invoicing terms is to provide customers with simplified and predictable ways of purchasing the Company’s products and services, not to facilitate financing arrangements.

Accrued research and development expenses

As part of the process of preparing financial statements, we are required to estimate and accrue research and development expenses. This process involves the following:

•

communicating with our applicable personnel to identify services that have been performed on our behalf and estimating the level of service performed and the associated cost incurred for the service when we have not yet been invoiced or otherwise notified of actual cost;

•

estimating and accruing expenses in our consolidated financial statements as of each balance sheet date based on facts and circumstances known to us at the time; and

•

periodically confirming the accuracy of our estimates with selected service providers and making adjustments, if necessary.

Examples of estimated research and development expenses that we accrue include:

•

fees paid to investigative sites in connection with clinical studies;

•

fees paid to contract manufacturing organizations in connection with non-clinical development, preclinical research, and the production of clinical study materials; and

•

professional service fees for consulting and related services.

We base our expense accruals related to non-clinical development, preclinical studies, and clinical trials on our estimates of the services received and efforts expended pursuant to contracts with organizations/consultants that conduct and manage clinical studies on our behalf. The financial terms of these agreements vary from contract to contract and may result in uneven payment flows. Payments under some of these contracts may depend on many factors, such as the successful enrollment of patients, site initiation, and the completion of clinical study milestones.

Our service providers invoice us monthly in arrears for services performed. In accruing service fees, we estimate the time period over which services will be performed and the level of effort to be expended in each period. If we do not identify costs that we have begun to incur, or if we underestimate or overestimate the level of services performed or the costs of these services, our actual expenses could differ from our estimates. To date, we have not experienced significant changes in our estimates of accrued research and development expenses after a reporting period. However, due to the nature of estimates, we cannot assure you that we will not make changes to our estimates in the future as we become aware of additional information about the status or conduct of our clinical trials and other research activities.

Stock-Based Compensation

Stock options

We recognize compensation costs related to awards granted to employees and directors, based on the estimated fair value of the awards on the date of grant. For stock options, we estimate the grant date fair value, and the resulting

stock-based compensation, using the Black-Scholes option-pricing model. The grant date fair value of the stock-based awards is recognized on a straight-line basis over the requisite service period, which is generally the vesting period of the respective awards.

The Black-Scholes option-pricing model requires the use of subjective assumptions to determine the fair value of stock options. These key subjective assumptions include:

•

Expected term—The expected term represents the period that stock options are expected to be outstanding. The expected term is determined using the simplified method. The simplified method deems the expected term to be the midpoint between the vesting date and the contractual life of the stock options.

•

Expected volatility— We estimate our expected share price volatility based on a blend of our historical volatility and the historical volatility of publicly traded peer companies and expect to continue to do so until such time as we have adequate historical data regarding the volatility of our own traded share price. The comparable companies were chosen based on their similar size, stage in the life cycle or area of specialty.

The following table presents the weighted-average assumptions used to estimate the fair value of share-based awards granted:

Year ended December 31,

Expected dividend yield 0% 0%

Expected volatility 80-81% 79 %

We will continue to use judgment in evaluating the assumptions utilized for the grant-date fair value of our stock options on a prospective basis.

Other Information

Net operating loss carryforwards

The reconciliation tax bill, commonly known as the “One Big Beautiful Bill Act” (OBBBA) into law July 4, 2025, which is considered the enactment date under U.S. generally accepted accounting principal (GAAP). Based on the OBBBA, we will make a method change to accelerate unamortized domestic R&D amounts ratably over the 2025 and 2026 taxable years. Our deferred tax assets as of December 31, 2025 reflect the change in tax treatment for these expenditures.

In accordance with ASC 740, Accounting for Income Taxes, management of the Company has evaluated the positive and negative evidence bearing upon the realizability of its deferred tax assets and has determined that it is more likely than not that we will not recognize the net benefits of federal and state deferred tax assets. A full valuation allowance of $161.1 million and $165.6 million was established at December 31, 2025 and 2024, respectively. The change in the valuation allowance was a decrease of $4.5 million and an increase of $32.3 million in 2025 and 2024, respectively.

As of December 31, 2025, and 2024, we had federal NOL carryforwards of $301.7 million and $242.1 million, respectively, which may be available to reduce future taxable income. Our Federal NOLs were generated after December 31, 2018 and carryforward indefinitely. As of December 31, 2025, and 2024, we had state NOLs of $329.2 million and $261.5 million, respectively, which may be available to reduce future taxable income. The state NOLs expire at various dates beginning in 2035.

As of December 31, 2025 and 2024, we had federal research and development tax credit (“R&D Credit”) carryforwards of $21.3 million and $15.3 million, respectively, and state R&D Credit carryforwards of $10.5 million and $8.4 million, respectively. Both federal and state R&D Credit carryforwards may be available to reduce future tax liabilities and expire at various dates beginning in 2034.

The Internal Revenue Code of 1986, as amended (“IRC”), provides for a limitation of the annual use of NOLs, R&D Credits, and other tax attributes following certain ownership changes that could limit our ability to utilize NOL and R&D Credit carryforwards. Under IRC Sections 382 and 383 an ownership change is generally defined as a greater than 50% change (by value) in its equity ownership over a three-year period. We have experienced ownership changes in the past and based on the existing Section 382 limitations, $0.9 million and $0.02 million of existing Federal NOLs and R&D credits, respectively, will not be utilizable. We may experience additional ownership changes in the future because of subsequent shifts in our stock ownership. As a result, our ability to use our pre-change NOLs to offset taxable income, if any, is subject to limitations, which could potentially result in increased future tax liability. In addition, at the state level, there may be periods during which the use of NOLs is suspended or otherwise limited, which could accelerate or permanently increase state taxes owed.

We apply ASC 740 related to accounting for uncertainty in income taxes. Our reserves related to income taxes are based on a determination of whether, and how much of, a tax benefit taken by us in our tax filings or positions is more likely than not to be realized following resolution of any potential contingencies present related to the tax benefit. At December 31, 2025, and 2024 we had no unrecognized tax benefits. Interest and penalty charges, if any, related to unrecognized tax benefits would be classified as income tax expense in the accompanying consolidated statements of operations and comprehensive loss.

We file U.S. federal and state income tax returns with varying statute of limitations. As of the year ended December 31, 2025, there is no examination by U.S. tax authorities. Due to our net operating loss carryforwards, federal income tax returns from incorporation are still subject to examination. We file in several state tax jurisdictions and are subject to examination in years ranging from incorporation to 2025. To the extent that we have tax attribute carryforwards, the tax years in which the attribute was generated may still be adjusted upon examination by the IRS and the state tax authorities to the extent utilized in a future period.

For year ended December 31, 2025, we had $0.6 million of Federal income taxes paid.

Smaller Reporting Company Status

We are a “smaller reporting company,” meaning that our annual revenue is less than $100.0 million during the last completed fiscal year or the market value of our stock held by non-affiliates was less than $700.0 million as of the end of that fiscal year’s second fiscal quarter. We will continue to be a smaller reporting company until the first quarter of 2027. As a smaller reporting company we may choose to present only the two most recent fiscal years of audited financial statements in our Annual Report on Form 10-K and smaller reporting companies have reduced disclosure obligations regarding executive compensation.

Recently Issued Accounting Pronouncements

In December 2023, the Financial Accounting Standards Board (the "FASB") issued ASU 2023-09, “Income Taxes (Topic 740): Improvements to Income Tax Disclosures” (“ASU 2023-09”). ASU 2023-09 requires that an entity disclose specific categories in the effective tax rate reconciliation as well as provide additional information for reconciling items that meet a quantitative threshold and certain disclosures of state versus federal income tax expenses and taxes paid. ASC 2023-09 is effective for fiscal years beginning after December 15, 2024. We adopted the standard effective January 1, 2025 and there was no material impact to our consolidated financial statements.

In November 2024, the FASB issued ASU 2024-03 “Income Statement— Reporting Comprehensive Income—Expense Disaggregation Disclosures” (“ASU 2024-03”). ASU 2024-03 requires disaggregated disclosure of income statement expenses for public business entities. The ASU does not change the expense captions an entity presents on the face of the income statement; rather, it requires disaggregation of certain expense captions into specified categories in disclosures within the footnotes to the financial statements. ASU 2024-03 is effective for fiscal years beginning after December 15, 2026. We are still evaluating the impact of ASU 2024-03 and have not yet determined whether its adoption will have a material effect on our consolidated financial statements.

Item 7A. Quantitative and Qualitative Disclosures About Market Risk.

Interest rate risk

We are exposed to market risks in the ordinary course, primarily including interest sensitivities. As of December 31, 2025, we had cash, cash equivalents and marketable securities of $390.9 million and $246.7 million as of December 31, 2024. Our primary exposure to market risk is interest rate sensitivity, which is affected by changes in the general level of U.S. interest rates. Because of the short-term maturities of our cash and cash equivalents, we do not believe that an immediate 10% increase in interest rates would have any significant impact on the realized value of our investments. Accordingly, we do not believe we are exposed to material market risk with respect to our cash and cash equivalents.

Inflation risk

Inflation generally affects us by increasing our clinical trial costs. We do not believe that inflation has had a material effect on our business, financial condition or results of operations during the years ended December 31, 2025 and 2024.

Item 8. Financial Statements and Supplementary Data.

The financial statements required to be filed pursuant to this Item 8 are appended to this report. An index of those financial statements is found in Item 15 of Part IV of this Annual Report on Form 10-K.

Item 9. Changes in and Disagreements With Accountants on Accounting and Financial Disclosure.

None.

Item 9A. Controls and Procedures.

Management’s Evaluation of Disclosure Controls and Procedures

Under the supervision and with the participation of our management, including our Chief Financial Officer (our principal accounting officer) and Chief Executive Officer (our principal executive officer), we evaluated the effectiveness of the design and operation of our disclosure controls and procedures (as defined in Rules 13a-15(e) and 15d-15(e) under the Securities Exchange Act of 1934, as amended (Exchange Act)) as of December 31, 2025. The term “disclosure controls and procedures,” as defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act, means controls and other procedures of a company that are designed to ensure that information required to be disclosed by a company in the reports that it files or submits under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in the SEC’s rules and forms. Disclosure controls and procedures include, without limitation, controls and procedures designed to ensure that information required to be disclosed by a company in the reports that it files or submits under the Exchange Act is accumulated and communicated to the company’s management, including its principal executive and principal financial officers, as appropriate, to allow timely decisions regarding required disclosure. Management recognizes that any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving their

objectives and management necessarily applies its judgment in evaluating the cost-benefit relationship of possible controls and procedures. Based on our management’s evaluation (with the participation of our Chief Executive Officer and our Chief Financial Officer), as of the end of the period covered by this report, our Chief Executive Officer and our Chief Financial Officer have concluded that our disclosure controls and procedures were effective at the reasonable assurance level.

Management’s Annual Report on Internal Control over Financial Reporting

Our management is responsible for establishing and maintaining adequate internal control over financial reporting as defined in Rule 13a-15(f) of the Exchange Act. Management assessed the effectiveness of our internal control over financial reporting as of December 31, 2025. In making this assessment, management used the criteria set forth by the Committee of Sponsoring Organizations of the Treadway Commission (COSO) in Internal Control—Integrated Framework issued in 2013. Based upon the assessments, management has concluded that as of December 31, 2025 our internal control over financial reporting was effective to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements in accordance with GAAP.

This Annual Report on Form 10-K does not include an attestation report from our independent registered public accounting firm because, for so long as we remain a “smaller reporting company,” our independent registered public accounting firm is not required to attest to the effectiveness of our internal control over financial reporting.

Changes in Internal Control over Financial Reporting

There has been no change in our internal control over financial reporting (as defined in Rules 13a-15(f) and 15d-15(f) of the Exchange Act) during three months ended December 31, 2025 that has materially affected, or is reasonably likely to materially affect, our internal control over financial reporting.

Inherent Limitations on Effectiveness of Controls

Internal control over financial reporting may not prevent or detect all errors and all fraud. Any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving the desired control objective and management necessarily applies its judgment in evaluating the cost-benefit relationship of possible controls and procedures.

Item 9B. Other Information.

Trading Arrangements

During the three months ended December 31, 2025, none of our directors or officers, as defined in Rule 16a-1(f), informed us of the adoption, modification or termination of a “Rule 10b5-1 trading arrangement” or “non-Rule 10b5-1 trading arrangement,” as those terms are defined in Regulation S-K, Item 408, except as described in the table below:

*Intended to satisfy the affirmative defense of Rule 10b5-1(c) of the Act.

**Not intended to satisfy the affirmative defense of Rule 10b5-1(c) of the Act.

(1)

Except as indicated by footnote, each trading arrangement permitted or permits transactions through and including the earlier of (a) the completion of all purchases or sales or (b) the date listed in the table.

(2)

of common stock available for sale includes 8,695 shares, which reflects the aggregate maximum number of shares underlying such awards and available for sale under the Rule 10b5-1 Plan without excluding the shares that will be sold to satisfy the tax withholding obligations.

(3)

The aggregate number of shares of common stock that will be available for sale under the Rule 10b5-1 Plan is not yet determinable because the shares available will be net of shares sold under Mr. Krainer’s prior Rule 10b5-1 Plan dated August 15, 2025. As such, for purposes of this disclosure, the aggregate number of shares of common stock available for sale includes 121,416 shares, which reflects the aggregate maximum number of shares available for sale under the Rule 10b5-1 Plan without excluding shares that may be sold under such prior Rule 10b5-1 Plan.

(4)

The aggregate number of shares of common stock that will be available for sale under the Rule 10b5-1 Plan is not yet determinable because the shares available will be net of shares sold to satisfy tax withholding obligations that arise in connection with the vesting and settlement of certain restricted stock unit and performance stock unit awards subject to the Rule 10b5-1 Plan. As such, for purposes of this disclosure, the aggregate number of shares of common stock available for sale includes 52,286 shares, which reflects the aggregate maximum number of shares underlying such awards and available for sale under the Rule 10b5-1 Plan without excluding the shares that will be sold to satisfy the tax withholding obligations.

Each new Rule 10b5-1 Plan that was adopted in the above table includes a representation from the director or officer, respectively, to the broker administering the plan that he was not in possession of any material nonpublic information regarding the Company or the securities subject to the Rule 10b5-1 Plan at the time the Rule 10b5-1 Plan was entered into. A similar representation was made to us in connection with the adoption of the Rule 10b5-1 Plan under our insider trading policy. Those representations were made as of the Adoption Date set forth above, and speak only as of that date. In making those representations, there is no assurance with respect to any material nonpublic information of which the directors and officers was unaware, or with respect to any material nonpublic information acquired by the above directors and officers or passage after the date of the representation.

Once executed, transactions under a Rule 10b5-1 Plan adopted during the period described above will be disclosed publicly through Form 4 and/or Form 144 filings with the SEC in accordance with applicable securities laws, rules, and regulations. Except as may be required by law, we do not undertake any obligation to update or report any modification, termination, or other activity under current or future Rule 10b5-1 plans that may be adopted by officers or directors of the Company.

Item 9C. Disclosure Regarding Foreign Jurisdictions That Prevent Inspections.

None.

PART III

Item 10. Directors, Executive Officers and Corporate Governance.

The information required by this Item 10 will be included in our Definitive Proxy Statement to be filed with the Securities and Exchange Commission (the “SEC”) with respect to our 2026 Annual Meeting of Stockholders and is incorporated herein by reference.

We have adopted a Code of Conduct that applies to all of our officers, directors, and employees, including our principal executive officer, principal financial officer, principal accounting officer, and controller, or persons performing similar functions, which is posted on our website. Our Code of Conduct is a “code of ethics,” as defined in Item 406(b) of Regulation S-K. We will make any legally required disclosures regarding amendments to, or waivers of, provisions of our Code of Conduct on our website. The information contained on, or accessible from, our website is not part of this Annual Report on Form 10-K by reference or otherwise.

Item 11. Executive Compensation.

The information required by this Item 11 will be included in our Definitive Proxy Statement to be filed with the SEC with respect to our 2026 Annual Meeting of Stockholders and is incorporated herein by reference.

Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters.

The information required by this Item 12 will be included in our Definitive Proxy Statement to be filed with the SEC with respect to our 2026 Annual Meeting of Stockholders and is incorporated herein by reference.

Item 13. Certain Relationships and Related Transactions, and Director Independence.

The information required by this Item 13 will be included in our Definitive Proxy Statement to be filed with the SEC with respect to our 2026 Annual Meeting of Stockholders and is incorporated herein by reference.

Item 14. Principal Accountant Fees and Services.

The information required by this Item 14 will be included in our Definitive Proxy Statement to be filed with the SEC with respect to our 2026 Annual Meeting of Stockholders and is incorporated herein by reference.

PART IV

Item 15. Exhibits, Financial Statement Schedules.

(a) The following documents are filed as a part of this Form 10-K:

Financial Statements

Our consolidated financial statements are listed in the “Index to Consolidated Financial Statements” under Part II, Item 8 of this Form 10-K.

Financial Statement Schedules

Financial statement schedules not listed have been omitted because they are not applicable, or the required information is shown in the consolidated financial statements or notes thereto.

Exhibits

10.15 Non-Employee Director Compensation Policy, as amended X

19.1 Insider Trading Policy X

23.1 Consent of independent registered public accounting firm. X

101.INS Inline XBRL Instance Document. X

101.SCH Inline XBRL Taxonomy Extension Schema Document. X

† Registrant has omitted certain portions of the exhibit pursuant to Item 601(b)(10) of Regulation S-K.

* Indicates a management contract or compensatory plan or arrangement in which directors or executive officers are eligible to participate.

** The certifications furnished in Exhibits 32.1 and 32.2 hereto are deemed to accompany this Form 10-K and are not deemed “filed” for purposes of Section 18 of the Exchange Act, or otherwise subject to the liability of that section, nor shall they be deemed incorporated by reference into any filing under the Securities Act or the Exchange Act.

# Registrant has omitted schedules and exhibits pursuant to Item 601(a)(5) of Regulation S-K. The Registrant agrees to furnish supplementally a copy of the omitted schedules and exhibits to the SEC upon request.

Item 16. Form 10-K Summary

None.

SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, as amended, the Registrant has duly caused this Annual Report on Form 10-K to be signed on its behalf by the undersigned, thereunto duly authorized.

STOKE THERAPEUTICS, INC.

Date: March 16, 2026 By: /s/ Ian F. Smith

Ian F. Smith

Chief Executive Officer

(Principal Executive Officer)

POWER OF ATTORNEY

Each person whose individual signature appears below hereby authorizes and appoints Ian F. Smith and Thomas E. Leggett, and each of them, with full power of substitution and re-substitution and full power to act without the other, as his or her true and lawful attorney-in-fact and agent to act in his or her name, place and stead and to execute in the name and on behalf of each person, individually and in each capacity stated below, and to file any and all amendments to this Annual Report on Form 10-K and to file the same, with all exhibits thereto, and other documents in connection therewith, with the Securities and Exchange Commission, granting unto said attorneys-in-fact and agents, and each of them, full power and authority to do and perform each and every act and thing, ratifying and confirming all that said attorneys-in-fact and agents or any of them or their or his substitute or substitutes may lawfully do or cause to be done by virtue thereof.

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, this Annual Report on Form 10-K has been signed below by the following persons on behalf of the Registrant in the capacities and on the dates indicated.

Name Title Date

/s/ Ian F. Smith Chief Executive Officer and Director March 16, 2026

Ian F. Smith (Principal Executive Officer)

/s/ Thomas E. Leggett Chief Financial Officer March 16, 2026

Thomas E. Leggett (Principal Financial and Accounting Officer)

/s/ Julie A. Smith Director March 16, 2026

Julie A. Smith

/s/ Seth L. Harrison Director March 16, 2026

Seth L. Harrison, M.D.

/s/ Adrian R. Krainer Director March 16, 2026

Adrian R. Krainer, Ph.D.

/s/ Arthur A. Levin Director March 16, 2026

Arthur A. Levin, Ph.D.

/s/ Edward M. Kaye M.D. Director March 16, 2026

Edward M. Kaye M.D

/s/ Jennifer C. Burstein Director March 16, 2026

Jennifer C. Burstein

/s/ Garry E. Menzel Director March 16, 2026

Garry E. Menzel

/s/ Arthur O. Tzianabos Chairman of the Board of Directors March 16, 2026

Arthur O. Tzianabos, Ph.D.

STOKE THERAPEUTICS, INC.

INDEX TO CONSOLIDATED FINANCIAL STATEMENTS

Page

Report of Independent Registered Public Accounting Firm 97

Consolidated balance sheets 99

Consolidated statements of operations and comprehensive loss 100

Consolidated statements of stockholders’ equity 101

Consolidated statements of cash flows 102

Notes to consolidated financial statements 103

Report of Independent Registered Public Accounting Firm

To the Stockholders and the Board of Directors

Stoke Therapeutics, Inc.:

Opinion on the Consolidated Financial Statements

We have audited the accompanying consolidated balance sheets of Stoke Therapeutics, Inc. and subsidiary (the Company) as of December 31, 2025 and 2024, the related consolidated statements of operations and comprehensive loss, stockholders’ equity, and cash flows for the years then ended, and the related notes (collectively, the consolidated financial statements). In our opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2025 and 2024, and the results of its operations and its cash flows for the years then ended, in conformity with U.S. generally accepted accounting principles.

Basis for Opinion

These consolidated financial statements are the responsibility of the Company’s management. Our responsibility is to express an opinion on these consolidated financial statements based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (PCAOB) and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the consolidated financial statements are free of material misstatement, whether due to error or fraud. The Company is not required to have, nor were we engaged to perform, an audit of its internal control over financial reporting. As part of our audits, we are required to obtain an understanding of internal control over financial reporting but not for the purpose of expressing an opinion on the effectiveness of the Company’s internal control over financial reporting. Accordingly, we express no such opinion.

Our audits included performing procedures to assess the risks of material misstatement of the consolidated financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the consolidated financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the consolidated financial statements. We believe that our audits provide a reasonable basis for our opinion.

Critical Audit Matter

The critical audit matter communicated below is a matter arising from the current period audit of the consolidated financial statements that was communicated or required to be communicated to the audit committee and that: (1) relates to accounts or disclosures that are material to the consolidated financial statements and (2) involved our especially challenging, subjective, or complex judgments. The communication of a critical audit matter does not alter in any way our opinion on the consolidated financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing a separate opinion on the critical audit matter or on the accounts or disclosures to which it relates.

Evaluation of distinct performance obligations related to the license and collaboration agreement with Biogen International GmbH

As discussed in Note 8 to the consolidated financial statements, the Company entered into an Exclusive License and Collaboration Agreement with Biogen International GmbH (Biogen). At contract inception, the Company assesses whether the goods or services promised within the contract are distinct and, therefore, represent a separate performance obligation, or whether they are not distinct and are combined with other goods and services until a distinct bundle is identified. The Company allocates the transaction price based on the estimated standalone selling price of the underlying performance obligations or in the case of certain variable consideration to one or more performance obligations. The Company identified two performance obligations under the license and collaboration agreement with Biogen. Fixed consideration of $165.0 million and estimated variable consideration of $78.4 million were allocated to the performance obligations based on their relative standalone selling price.

We identified the evaluation of distinct performance obligations, including understanding the nature and significance of the contractual obligations and their standalone selling prices, related to the license and collaboration agreement with Biogen as a critical audit matter. Subjective and complex auditor judgment was required to assess the Company’s identification of distinct performance obligations, including evaluating the rights and obligations described in the agreement, their benefit to the customer and the level of modification or customization among the performance obligations. In addition, subjective auditor judgment was required to evaluate certain significant assumptions in the discounted cash flow model used by management to determine the standalone selling price of the IP License, including the discount rates and certain underlying assumptions to the forecasted net sales such as prevalent population, diagnosis and treatment rates, and price. The audit effort associated with assessing the discount rate assumptions required specialized skills and knowledge.

The following are the primary procedures we performed to address this critical audit matter. We evaluated management’s identification of distinct performance obligations and the significance of the contractual obligations by obtaining and reading the license and collaboration agreement to gain an understanding of the contractual terms and conditions and the commitments being made in the agreement. We conducted inquiries with personnel responsible for clinical development to understand the nature of the research and development activities specific to the clinical development and commercialization stage programs to evaluate the nature of the commitments made to the customer. We evaluated management’s accounting analysis and assessed the reasonableness of management’s judgments and assumptions in the determination of distinct performance obligations and the significance of the contractual obligations by comparing them to underlying documentation. We evaluated the Company’s forecasted net sales used in the fair value analysis by obtaining an understanding of the significant assumptions noted above underlying the forecasted net sales and comparing such assumptions to underlying documentation, including external population data, published medical data, and comparable drug information. We involved valuation professionals with specialized skills and knowledge, who assisted in the evaluation of the discount rates by comparing them to an independently developed discount rate range.

/s/ KPMG LLP

We have served as the Company’s auditor since 2019.

Boston, Massachusetts

March 16, 2026

Stoke Therapeutics, Inc. and subsidiary

Consolidated balance sheets

(in thousands, except share and per share amounts)

As of December 31,

Assets

Current assets:

Restricted cash - short term 494 75

Restricted cash - long term 227 721

Operating lease right-of-use assets 3,101 4,345

Liabilities and stockholders’ equity

Current liabilities:

Accrued and other current liabilities 41,035 18,567

Deferred revenue - net of current portion 6,961 —

Total long term liabilities $ 8,102 $ 2,478

Commitments and contingencies (Note 7)

Stockholders’ equity

Accumulated other comprehensive income (loss) 543 (151 )

Total liabilities and stockholders’ equity $ 418,434 $ 271,555

The accompanying notes are an integral part of these consolidated financial statements.

Stoke Therapeutics, Inc. and subsidiary

Consolidated statements of operations and comprehensive loss

(in thousands, except share and per share amounts)

Year EndedDecember 31,

Operating expenses:

Other income (expense):

Other income (expense), net (51 ) (247 )

Net loss per share—basic and diluted $ (0.12 ) $ (1.65 )

Comprehensive loss:

Other comprehensive loss:

Unrealized gain (loss) on marketable securities 694 (127 )

Total other comprehensive gain (loss) $ 694 $ (127 )

The accompanying notes are an integral part of these consolidated financial statements.

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Stoke Therapeutics, Inc. and subsidiary

Consolidated statements of stockholders’ equity

(in thousands, except share and per share amounts)

Shares Amount

Unrealized loss on marketable securities — — — (127 ) — (127 )

Unrealized gain on marketable securities — — — 694 — 694

The accompanying notes are an integral part of these consolidated financial statements.

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Stoke Therapeutics, Inc. and subsidiary

Consolidated statements of cash flows

(in thousands)

Year Ended December 31,

Cash flows from operating activities:

Adjustments to reconcile net loss to net cash used in operating activities:

Amortization and accretion of marketable securities (1,133 ) (1,642 )

Impairment of right of use asset 696 —

Loss on disposal of property and equipment 145 —

Reduction in the carrying amount of right of use assets 2,408 2,265

Changes in assets and liabilities:

Accounts receivable (4,268 ) (50 )

Prepaid expenses and other current assets (545 ) (1,786 )

Accounts payable, accrued liabilities, and operating leases 21,289 3,088

Net cash provided by (used in) operating activities 45,585 (86,851 )

Cash flows from investing activities:

Purchases of property and equipment (670 ) (203 )

Cash flows from financing activities:

Proceeds from employee stock purchase plan 1,002 532

Net cash provided by financing activities 97,389 131,094

Net decrease in cash, cash equivalents and restricted cash (43,838 ) (63,232 )

Cash, cash equivalents and restricted cash—beginning of year 128,779 192,011

Cash, cash equivalents and restricted cash—end of year $ 84,941 $ 128,779

Supplemental Disclosure of Non-Cash Investing and Financing Activities:

Right-of-use assets recognized in exchange for operating leases $ 1,776 $ —

The accompanying notes are an integral part of these consolidated financial statements.

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Stoke Therapeutics, Inc. and subsidiary

Notes to consolidated financial statements

(in thousands, except share and per share amounts)

1. Nature of the business and basis of presentation

Organization

Stoke Therapeutics, Inc. (the Company) was founded in June 2014 and was incorporated under the laws of the State of Delaware. The Company is a late-stage clinical company dedicated to addressing the underlying causes of severe diseases by upregulating protein expression with RNA-based medicines.

Shelf Registration

In May 2022, the Company filed a universal Shelf Registration statement on Form S-3 (the “2022 Registration Statement”) with the Securities and Exchange Commission (the “SEC”). The 2022 Registration Statement was declared effective by the SEC on May 31, 2022, and contained two prospectuses: a base prospectus, which covers the offering, issuance and sale by the Company of up to a maximum aggregate offering price of $400.0 million of its common stock, preferred stock, debt securities, warrants to purchase common stock, preferred stock or debt securities, subscription rights to purchase common stock, preferred stock or debt securities and/or units consisting of some or all of these securities; and a sales agreement prospectus covering the offering, issuance and sale by the Company of up to a maximum aggregate offering price of $150.0 million of its common stock that may be issued and sold under a Controlled Equity Offering Sales Agreement (the “Sales Agreement”). As of December 31, 2025, the Company had issued approximately 7.0 million shares of common stock pursuant to the Sales Agreement and the 2022 Registration Statement for net proceeds of $61.0 million.

In April 2024, the Company completed an underwritten public offering of its common stock and issued and sold 5,555,557 shares of common stock at a public offering price of $13.50 per share and issued pre-funded warrants to purchase 3,703,730 shares of common stock at a public offering price of $13.499 per share subject to an exercise price equal to $0.0001 pursuant to the 2022 Registration Statement. The common stock and pre-funded warrants sold resulted in net proceeds of approximately $119.9 million after deducting underwriting discounts, commissions and offering costs.

In October 2024, the Company filed an automatic universal Shelf Registration statement on Form S-3 (the “2024 Registration Statement”) with the SEC. Following the filing of the Company’s Annual Report on Form 10-K for the year ended December 31, 2024 in March 2025, the 2024 Registration Statement became ineffective.

In July 2025, the Company filed a universal Shelf Registration statement on Form S-3 (the “2025 Registration Statement”) with the SEC. The 2025 Registration Statement was declared effective by the SEC on July 11, 2025, and contains two prospectuses: a base prospectus, which covers the offering, issuance and sale by the Company of up to a maximum aggregate offering price of $400.0 million of the Company’s common stock, preferred stock, debt securities, warrants to purchase common stock, preferred stock or debt securities, subscription rights to purchase common stock, preferred stock or debt securities and/or units consisting of some or all of these securities; and a sales agreement prospectus covering the offering, issuance and sale by the Company of up to a maximum aggregate offering price of $150.0 million of common stock that may be issued and sold under the Sales Agreement. The specific terms of any securities to be offered pursuant to the base prospectus will be specified in a prospectus supplement to the base prospectus. As of December 31, 2025, the Company had issued approximately 3.2 million shares of common stock pursuant to the Sales Agreement and the 2025 Registration Statement for net proceeds of $87.8 million.

Uncertainties

The Company is subject to risks and uncertainties common to early-stage companies in the biotechnology industry including, but not limited to, development by competitors of new technological innovations, dependence on key personnel, protection of proprietary technology, compliance with government regulations and ability to secure additional capital to fund operations. Product candidates currently under development will require significant additional research and development efforts, including extensive preclinical and clinical testing and regulatory approval prior to commercialization. These efforts require significant amounts of additional capital, adequate personnel and infrastructure and extensive compliance-reporting capabilities. Even if the Company’s product development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales.

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Liquidity

The Company expects that its operating losses and negative cash flows will continue for the foreseeable future. As of the issuance date of these consolidated financial statements, the Company expects that its cash, cash equivalents, marketable securities and restricted cash will be sufficient to fund its operating expenses and capital expenditure requirements through at least twelve months from the issuance date of these consolidated financial statements.

2. Summary of significant accounting policies and recent accounting pronouncements

Basis of presentation and consolidation

The accompanying consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (GAAP), and include the accounts of Stoke Therapeutics, Inc. and its wholly-owned subsidiary. Any reference in these notes to applicable guidance is meant to refer to GAAP as found in the Accounting Standards Codification (“ASC”) and Accounting Standards Update (“ASU”) of the Financial Accounting Standards Board (“FASB”). All intercompany transactions between and among the Company and its consolidated subsidiary have been eliminated.

Reclassification

The Company reclassified $1.7 million of Other current assets as of December 31, 2024 to Accounts receivable in its Consolidated balance sheets to conform to the current year presentation.

Use of estimates

The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, equity, revenue, expenses and disclosure of contingent assets and liabilities. Estimates are periodically reviewed in light of changes in circumstances, facts and experience. Actual results could differ from those estimates.

Cash and cash equivalents

The Company considers all highly liquid investments with an original maturity of three months or less at the date of purchase to be cash equivalents. The Company deposits its cash in checking, sweep and money market accounts.

Restricted cash

At December 31, 2025, restricted cash consisted of money market accounts collateralizing letters of credit issued as security deposits in connection with the Company’s leases of its corporate facilities.

The following table reconciles cash and cash equivalents and restricted cash per the consolidated balance sheets to the statements of cash flows:

As of December 31,

Marketable Securities

Marketable securities consist of government securities and obligations, corporate bonds and commercial paper with original maturities of more than 90 days at the purchase date. Investments are classified as available-for-sale and are recorded on the balance sheet at fair value with unrealized gains or losses reported as a separate component of other comprehensive income (loss). Management determines the appropriate classification of its investments at the time of purchase and reevaluates such determination at each balance sheet date. Marketable securities are classified as current assets or non-current assets based on each security’s time to maturity as of the balance sheet date.

Concentration of credit risk

Financial instruments that potentially expose the Company to concentrations of credit risk primarily consist of cash, cash equivalents and marketable securities. The Company maintains its cash, cash equivalents and marketable securities at

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accredited financial institutions in amounts that exceed federally insured limits. The Company does not believe that it is subject to unusual credit risk beyond the normal credit risk associated with commercial banking relationships.

Fair value of financial instruments

ASC Topic 820, Fair Value Measurement (ASC 820), establishes a fair value hierarchy for instruments measured at fair value that distinguishes between assumptions based on market data (observable inputs) and the Company’s own assumptions (unobservable inputs). Observable inputs are those that market participants would use in pricing the asset or liability based on market data obtained from sources independent of the Company. Unobservable inputs are inputs that reflect the Company’s assumptions about the inputs that market participants would use in pricing the asset or liability and are developed based on the best information available in the circumstances. ASC 820 identifies fair value as the exchange price, or exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As a basis for considering market participant assumptions in fair value measurements, ASC 820 establishes a three-tier value hierarchy that distinguishes between the following:

Level 1—Quoted market prices in active markets for identical assets or liabilities.

Level 2—Inputs other than Level 1 inputs that are either directly or indirectly observable, such as quoted market prices, interest rates and yield curves.

Level 3—Unobservable inputs developed using estimates of assumptions developed by the Company, which reflect those that a market participant would use.

To the extent the valuation is based on models or inputs that are less observable or unobservable in the market, the determination of fair values requires more judgment. Accordingly, the degree of judgment exercised by the Company in determining fair value is greatest for instruments categorized as Level 3. A financial instrument’s level within the fair value hierarchy is based on the lowest level of any input that is significant to the fair value measurement.

Revenue Recognition under ASC 606

For revenue arrangements accounted for under ASC 606, the Company recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services. To determine the appropriate amount of revenue to be recognized for arrangements determined to be within the scope of ASC 606, the Company performs the following five steps: (i) identification of the contract; (ii) determination of whether the promised goods or services are performance obligations; (iii) measurement of the transaction price, including evaluating the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations; and (v) recognition of revenue when (or as) the Company satisfies each performance obligation. The Company applies the five-step model to all contracts, including transactions with collaborators or partners, if they are a transaction with a customer.

Performance obligations are promises to transfer distinct goods or services to the customer. Promised goods or services are considered distinct when (i) the customer can benefit from the good or service on its own or together with other readily available resources and (ii) the promised good or service is separately identifiable from other promises in the contract. In assessing whether promised goods or services are distinct, the Company considers factors such as the stage of development of the underlying intellectual property, the capabilities of the customer to develop the intellectual property on their own, or whether the required expertise is readily available.

The Company estimates the transaction price based on the amount expected to be received for transferring the promised goods or services in the contract. The consideration may include both fixed consideration and variable consideration. At the inception of an arrangement that includes variable consideration and at each reporting period, the Company evaluates the amount of potential payment and the likelihood that the payments will be received. The Company utilizes either the most likely amount method or expected amount method to estimate the amount to be received based on which method better predicts the amount expected to be received. If it is probable that a significant reversal of cumulative revenue would not occur, the variable consideration is included in the transaction price. The Company will assess its revenue generating arrangements in order to determine whether a significant financing component exists and conclude that a significant financing component does not exist in any of its arrangements if: (a) the promised consideration approximates the cash selling price of the promised goods and services or any significant difference is due to factors other than financing; and (b) timing of payment approximates the transfer of goods and services and performance is over a relatively short period of time within the context of the entire term of the contract.

Contracts may include pre-commercial milestone payments. At contract inception and at each reporting period, the Company assesses whether achievement of the milestone was most likely and whether it is probable that a significant reversal in the amount of cumulative revenue recognized would not occur. If it is probable that a significant reversal of cumulative revenue would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company’s control or the customer’s control are constrained and not included in the transaction price. At the end

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of each subsequent reporting period, the Company re-evaluates the probability of achievement of such milestones and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch-up basis, which would affect revenues and earnings in the period of adjustment.

For arrangements that may include sales-based royalties, including milestone payments based on the level of sales, and the license is deemed to be the predominant item to which the royalties relate, the Company recognizes revenue at the later of (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). To date, the Company has not recognized any royalty revenue resulting from any of the Company’s collaboration arrangements.

The Company allocates the transaction price based on the estimated standalone selling price of the underlying performance obligations or in the case of certain variable consideration to one or more performance obligations. The Company must develop assumptions that require judgment to determine the stand-alone selling price for each performance obligation identified in the contract. The Company utilizes a range of key assumptions to determine the stand-alone selling price, which may include prices observed in comparable market transactions, pricing considered in negotiating the transaction, the estimated costs, plus a reasonable margin, forecasted revenue, development timelines, reimbursement rates for personnel costs, discount rates and probabilities of success in achieving various pre-commercial and commercial milestones, to complete the respective performance obligation. Certain variable consideration is allocated specifically to one or more performance obligations in a contract when the terms of the variable consideration relate to the satisfaction of the performance obligation and the resulting amounts allocated to each performance obligation are consistent with the amounts the Company would expect to receive for each performance obligation.

For performance obligations consisting of licenses, research and development activities, and other promises, the Company utilizes judgment to assess the nature of the performance obligation to determine whether the performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. If the license to the Company’s intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, the Company will recognize revenue when the license is transferred to the customer and the customer is able to use and benefit from the license. Upfront payments and fees are recorded as deferred revenue upon receipt or when due until the Company performs its obligations under these arrangements. Amounts are recorded as accounts receivable when the right to consideration is unconditional, including unbilled amounts.

Payment terms and conditions vary by contract type, although terms typically require payment within 30 to 60 days. In instances where the timing of revenue recognition differs from that of invoicing, the Company has determined that its contracts generally do not include a significant financing component. The primary purpose of invoicing terms is to provide customers with simplified and predictable ways of purchasing the Company’s products and services, not to facilitate financing arrangements.

Deferred offering costs

The Company capitalizes certain legal, professional accounting and other third-party fees that are directly associated with in-process equity financings as deferred offering costs until such financings are consummated. After consummation of the equity financing, these costs are recorded in the consolidated statement of stockholders’ equity as a reduction of additional paid-in capital.

Property and equipment

Property and equipment are recorded at cost less accumulated depreciation. Cost includes the acquisition costs and all costs necessary to bring the asset to the location and working condition necessary for its intended use. Depreciation expense is recognized using the straight-line method over the estimated useful life of each asset. Upon retirement or sale, the cost of assets disposed of and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is included in the accompanying consolidated statements of operations and comprehensive loss. Expenditures for normal, recurring or periodic repairs and maintenance related to property and equipment are charged to expense as incurred. The cost for planned major maintenance activities, including the related acquisition or construction of assets, is capitalized if it will result in future economic benefits.

Estimated useful lives for property and equipment are as follows:

Property and equipment Estimated useful life

Computer and office equipment 3-5 years

Laboratory equipment and Furniture and fixtures 5-7 years

Leasehold improvements Lesser of estimated useful life or remaining lease term

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Impairment of long-lived assets

The Company reviews the recoverability of its long-lived assets when events or changes in circumstances occur that indicate that the carrying value of the assets may not be recoverable. The assessment of possible impairment is based on the ability to recover the carrying value of the assets from the expected future cash flows (undiscounted) of the related operations. If these cash flows are less than the carrying value of such assets, an impairment loss for the difference between the estimated fair value and carrying value is recorded. There were no impairment losses recognized during the years ended December 31, 2025 and 2024.

Research and development costs

Research and development costs are expensed as incurred. Research and development expenses are comprised of costs incurred in performing research and development activities, including salaries and benefits, facilities costs, depreciation, third-party license fees, and costs related to third parties engaged to conduct clinical trial and preclinical research development activities.

The Company has entered into various research and development contracts with research institutions and other companies to conduct research on its behalf. These agreements are generally cancellable. The Company records accruals for estimated ongoing research costs. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the studies, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates may be required in determining the accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates. The Company’s historical accrual estimates have not been materially different from the actual costs.

Stock-based compensation

The Company measures its stock-based awards granted based on the estimated fair values of the awards and recognizes the compensation expense for employees and non-employees over the requisite service period.

Stock options

The Company uses the Black-Scholes option-pricing model to estimate the fair value of its stock options.

The Company has elected the practical expedient to use the midpoint between vesting date and the contractual term as the expected term for certain awards with service or performance conditions. Stock-based compensation is recognized using the straight-line method. Forfeitures of unvested stock-based awards are accounted for when they occur.

Restricted stock units (“RSUs”)

For RSUs issued to employees, the Company recognizes the grant date fair value of the RSUs on a straight-line basis over the requisite service period, which is generally the vesting period of the respective awards. RSUs granted typically vest annually over a four-year period but may be granted with different vesting terms.

Performance stock units (“PSUs”)

For PSUs issued to employees, the Company recognizes the grant date fair value of the PSUs on a straight-line basis over the requisite service period, which is generally the vesting period of the respective awards. PSUs granted typically vest annually over a two-year period but may be granted with different vesting terms. The performance conditions required for achievement are predefined by the Company's Compensation Committee at the time of the grant. The awards only vest, and compensation expense is only recognized, if the performance condition is probable of achievement.

Patent costs

All patent-related costs incurred in connection with filing and prosecuting patent applications are expensed as incurred due to the uncertainty about the recovery of the expenditure. Amounts incurred are classified as sales, general and administrative expenses in the accompanying consolidated statements of operations and comprehensive loss.

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Incometaxes

The Company accounts for income taxes using the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the estimated future tax consequences attributable to temporary differences between the consolidated financial statement carrying amounts of existing assets and liabilities and their respective tax base. Deferred tax assets and liabilities are determined on the basis of the differences between the consolidated financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the temporary differences are expected to be settled or recovered. Changes in deferred tax assets and liabilities are recorded in the provision for income taxes. The Company assesses the likelihood that its deferred tax assets will be recovered from future taxable income and, to the extent it believes, based upon the weight of available evidence that it is more likely than not that all or a portion of the deferred tax assets will not be realized, a valuation allowance is established through a charge to income tax expense. Potential for recovery of deferred tax assets is evaluated by estimating the future taxable profits expected and considering prudent and feasible tax planning strategies. At December 31, 2025 and 2024, the Company has recorded a full valuation allowance.

Reserves are provided for tax benefits for which realization is uncertain. Such benefits are only recognized when the underlying tax position is considered more-likely-than-not to be sustained on examination by a taxing authority, assuming they possess full knowledge of the position and facts. Interest and penalties related to uncertain tax positions are recognized in the provision of income taxes; however, the Company currently has no interest or penalties related to uncertain income tax benefits.

Segment and geographic information

Operating segments are defined as components of an entity about which separate discrete information is available for evaluation by the chief operating decision maker, or decision-making group, in deciding how to allocate resources and in assessing performance.

The Company comprises of one reportable segment, Stoke. As of December 31, 2025, this segment has not generated any product revenue since inception, as it does not yet have approved products for sale.

The Company primarily generates revenue in North America, with its long-lived assets also concentrated in this region, and manages its business activities on a consolidated basis. Decisions concerning the allocation of the Company’s resources are made by the Company’s Chief Operating Decision Maker (“CODM”), which is the Company’s Chief Executive Officer (“CEO”). The CODM views the Company’s operations as a single operating segment which is the business of discovering and developing RNA-based medicines, using the TANGO approach and developing ASOs to selectively restore protein levels.

The CODM assesses performance for the Stoke operations segment and decides how to allocate resources based on net income or loss that is also reported on the income statement as consolidated net income or loss and the measure of segment assets as reported on the balance sheet as total consolidated assets. Net income or loss is used to monitor budget vs actual results as well as assess the general performance of the segment in a given period.

Smaller reporting company status

The Company is a “smaller reporting company,” meaning that its annual revenue was less than $100.0 million during the last completed fiscal year or the market value of the Company's stock held by non-affiliates was less than $700.0 million as of the end of that fiscal year’s second fiscal quarter. The Company expects to continue to be a smaller reporting company until the first quarter of 2027. As a smaller reporting company, the Company may choose to present only the two most recent fiscal years of audited financial statements in its Annual Report on Form 10-K and smaller reporting companies have reduced disclosure obligations regarding executive compensation.

Recently issued accounting pronouncements

In December 2023, the FASB issued ASU 2023-09, “Income Taxes (Topic 740): Improvements to Income Tax Disclosures” (“ASU 2023-09”). ASU 2023-09 requires that an entity disclose specific categories in the effective tax rate reconciliation as well as provide additional information for reconciling items that meet a quantitative threshold and certain disclosures of state versus federal income tax expenses and taxes paid. ASC 2023-09 is effective for fiscal years beginning after December 15, 2024. The Company adopted the standard effective January 1, 2025 and there was no material impact to its consolidated financial statements.

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expenses for public business entities. The ASU does not change the expense captions an entity presents on the face of the income statement; rather, it requires disaggregation of certain expense captions into specified categories in disclosures within the footnotes to the financial statements. ASU 2024-03 is effective for fiscal years beginning after December 15, 2026. The Company is still evaluating the impact of ASU 2024-03 and has not yet determined whether its adoption will have a material effect on its consolidated financial statements.

3. Fair value measurements

The following tables present information about the Company’s financial assets measured at fair value on a recurring basis and indicate the level of the fair value hierarchy utilized to determine such fair values:

Fair value measurements as ofDecember 31, 2025

Level 1 Level 2 Level 3 Total

Cash equivalents:

Marketable Securities:

US Government and US Government agency debt securities — 197,999 — 197,999

Fair value measurements as ofDecember 31, 2024

Level 1 Level 2 Level 3 Total

Cash equivalents:

Marketable Securities:

The Company’s cash equivalents and marketable securities are carried at fair value, determined according to the fair value hierarchy described above and in Note 2. The carrying value of the Company’s accounts payable and accrued expenses approximate their fair values due to the short-term nature of these liabilities.

The Company’s assets with fair value categorized as Level 1 within the fair value hierarchy include money market funds. Money market funds are publicly traded mutual funds and are presented as cash equivalents on the consolidated balance sheets as of December 31, 2025 and 2024.

The Company measures its marketable securities at fair value on a recurring basis and classifies those instruments within Level 2 of the fair value hierarchy.Marketable securities are valued using models or other valuation methodologies that use Level 2 inputs. These models are primarily industry-standard models that consider various assumptions, including time value, yield curve, volatility factors, default rates, current market and contractual prices for the underlying financial instruments, as well as other economic measures. Substantially all of these assumptions are observable in the marketplace, can be derived from observable data or are supported by observable levels at which transactions are executed in the marketplace.

There were no transfers to Level 3 in the periods presented.

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4. Marketable Securities

The following table summarizes the Company’s marketable securities as of December 31, 2025:

Amortized Cost Unrealized Gains Unrealized Loss Fair Value

Marketable Securities:

The following table summarizes the Company’s marketable securities as of December 31, 2024:

Amortized Cost Unrealized Gains Unrealized Loss Fair Value

Marketable securities:

The weighted average maturity of the Company’s marketable securities as of December 31, 2025 is approximately 0.81 years.

The Company did not record an allowance for credit losses as of December 31, 2025 related to our marketable securities. Further, given the lack of significant change in the credit risk of these investments, the Company did not recognize any other-than-temporary impairment losses.

5. Property and equipment, net

Property and equipment, net consisted of the following:

As of December 31,

Construction in progress 615 120

Less accumulated depreciation (10,146 ) (8,848 )

Depreciation expense was $1.8 million and $2.2 million for the years ended December 31, 2025 and 2024, respectively.

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6. Accrued and other current liabilities

Accrued and other current liabilities consisted of the following:

As of December 31,

Accrued employee compensation costs $ 13,975 $ 7,686

Accrued professional costs 965 1,108

Accrued research and development costs 22,028 6,698

Current portion of operating lease liabilities 3,007 2,322

7.Commitments and contingencies

Operating leases

The Company determines whether an arrangement is a lease at inception. The Company accounts for a lease when it has the right to control the leased asset for a period of time while obtaining substantially all of the assets’ economic benefits. Operating lease right-of-use assets and operating lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term at the lease commencement date. The discount rate used to determine the present value of the lease payments is the Company’s incremental borrowing rate based on the information available at lease inception, as the Company did not have information to determine the rate implicit in the leases. Lease expense for operating leases is recognized on a straight-line basis over the reasonably assured lease term based on the total lease payments (which include initial direct costs and lease incentives). Lease expense is included in operating expenses in the consolidated statements of operations and comprehensive loss. The Company’s lease agreements also contain variable payments, primarily maintenance-related costs, which are expensed as incurred and not included in the measurement of the right-of-use assets and lease liabilities.

In August 2018, the Company entered into an agreement to lease approximately 23,000 square feet of space for a term of three years. Lease terms are triple net lease commencing at $0.9 million per year, then with 3% annual base rent increases plus operating expenses, real estate taxes, utilities and janitorial fees. The lease commencement date was December 10, 2018.

In September 2021, the Company entered into an agreement to extend the initial term of the 23,000 square foot lease for a period of three years commencing on December 15, 2021 and ending December 31, 2024. In addition, this lease provides for the lease of an additional 15,000 square feet of rentable space beginning on April 1, 2022 and ending on December 31, 2024. In December 2021, the Company recognized a right-of-use asset and operating lease liability of $3.5 million for the 23,000 square feet. On April 1, 2022, the Company recognized a right-of-use asset and operating lease liability of $1.8 million for the 15,000 square feet. This lease expired on June 30, 2025.

In December 2023, the Company entered into an agreement to extend the term of the 38,000 square foot lease for a period of two years commencing on January 1, 2025 and ending on December 31, 2026. In December 2023, the Company recognized a right-of-use asset and operating lease liability of $4.1 million.

In December 2018, the Company entered into an agreement to lease 2,485 square feet of space for an initial term of three years. The lease includes one renewal option for an additional two years, however, any time after the initial term the landlord may relocate the Company from the premises to a space reasonably comparable in size and utility. As the Company does not have the right to control the use of the identified asset after the initial term, the renewal option was excluded from the lease liability calculation. Lease terms commence at $0.2 million per annum, with 2.5% annual base rent increases plus operating expenses, real estate taxes, utilities and janitorial fees. The lease commencement date was May 1, 2019.

In June 2021, the Company amended the agreement to extend the initial term of the 2,485 square foot lease for a period of three years commencing May 1, 2022 and ending April 30, 2025. In addition, the amendment provided for the lease of an additional 2,357 square feet of rentable space beginning on July 6, 2021 and ending on April 30, 2025. In March 2025, the Company further amended this lease to extend the term from April 30, 2025 to June 30, 2025. The amended lease provides the Company with the option to extend the term of the lease for an additional two years. In 2021, the Company recognized a right-of-use asset and operating lease liabilities of $0.7 million for the extension of the lease to April 30, 2025 and a right-of-use asset and operating lease liabilities of $0.8 million for the additional 2,357 square feet of rentable space.

In January 2025, the Company entered into an agreement to lease 7,581 square feet of space for an initial term of three years and three months. The lease includes two renewal options for an additional three years each. Lease terms commence at

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$0.7 million per annum, with 2% annual base rent increases plus operating expenses, real estate taxes, and utilities. The lease commencement date was July 8, 2025. In July 2025, the Company recognized a right-of-use asset and operating lease liability of $1.8 million. In September 2025, the Company entered into a sublease agreement for the 7,581 square feet of space for a term equal to the initial term of the original lease. Sublease terms commence at $0.4 million per annum with 2% annual rent increases. As a result of this sublease, the Company recognized a right of use asset impairment of $0.7 million.

Future minimum lease payments under non-cancellable leases as of December 31, 2025, were as follows:

Total lease payments 4,481

Less imputed interest (333 )

Present value of lease liabilities $ 4,148

Lease balances as of December 31, 2025 and December 31, 2024 were as follows:

As of December 31,

Operating right-of-use assets $ 3,101 $ 4,345

Current portion of operating lease liabilities $ 3,007 $ 2,322

Non-current portion of operating lease liabilities 1,141 2,452

Total operating lease liabilities $ 4,148 $ 4,774

The weighted average remaining lease term and weighted average discount rate of the Company's operating leases as of December 31, 2025 were as follows:

Weighted average remaining lease term in years 1.8

Weighted average discount rate 10.12 %

In accordance with Topic 842, lease expense incurred under operating leases was $2.8 million for the year ended December 31, 2025, and $2.8 million for the year ended December 31, 2024.

License and research agreements

In April 2016, the Company entered into an exclusive, worldwide license agreement with the University of Southampton (the “Southampton Agreement”), whereby the Company acquired rights to foundational technologies related to the Company’s TANGO technology. Under the Southampton Agreement, the Company receives an exclusive, worldwide license under certain licensed patents and applications relating to TANGO. Under the Southampton Agreement, the Company may be obligated to make additional payments that are contingent upon certain milestones being achieved, as well as royalties on future product sales. These royalty obligations survive until the latest of (i) the expiration of the last valid claim of a licensed patent covering a subject product or (ii) the expiration of any regulatory exclusivity for the subject product in a country. In addition, if the Company sublicenses its rights under the Southampton Agreement, the Company is required to pay a mid-single digit percentage of the sublicense revenue to the University of Southampton. As of December 31, 2025, the Company had paid $0.7 million under the Southampton Agreement as a result of entering into the Acadia Pharmaceuticals Inc. license and collaboration agreement in January 2022 and recorded a liability of $8.2 million for a sublicense fee expense, due to the Biogen license and collaboration agreement (see Note 8). Additionally, certain licenses under the Southampton Agreement require the Company to reimburse the University of Southampton for certain past and ongoing patent related expenses. For the year ended December 31, 2025 these expenses were $0.1 million compared to $0.1 million for the year ended December 31, 2024.

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Litigation

The Company may periodically become subject to legal proceedings and claims arising in connection with ongoing business activities, including claims or disputes related to patents that have been issued or that are pending in the field of research on which it is focused. As of December 31, 2025, the Company had no legal proceedings to which it was a party or to which its property was subject that, in the opinion of management, would have a material adverse effect on its business.

8. License and collaboration agreements

Acadia Pharmaceuticals Inc.

In January 2022, the Company entered into a License and Collaboration Agreement (the “Acadia Agreement”) with Acadia Pharmaceuticals Inc. (“Acadia”) for the discovery, development and commercialization of novel RNA-based medicines for the treatment of severe and rare genetic neurodevelopmental diseases of the central nervous system. The Acadia Agreement focused on the targets SYNGAP1, MECP2 (Rett syndrome), and an undisclosed neurodevelopmental target of mutual interest. In connection with each target, the Company agreed to collaborate with Acadia to identify potential treatments for further development and commercialization as licensed products. With respect to SYNGAP1, the Company agreed with Acadia to co-develop and co-commercialize licensed products for such target globally, and in connection therewith the Company granted to Acadia worldwide, co-exclusive (with the Company) licenses for such licensed products. With respect to MECP2 and the neurodevelopmental target, the Company granted Acadia worldwide, exclusive licenses to develop and commercialize licensed products for such targets. Effective as of September 3, 2025, Acadia terminated the MECP2 and the undisclosed neurodevelopmental programs under the Acadia Agreement (the “Discontinued Acadia Programs”) and rights to these targets returned to the Company. The collaboration with Acadia with respect to SYNGAP1 remains ongoing.

Pursuant to the terms of the Acadia Agreement, the Company received an upfront payment of $60.0 million from Acadia. Acadia agreed to fund the research for the Discontinued Acadia Programs, and the Company will equally fund with Acadia the research to identify potential licensed products for SYNGAP1. The Company is eligible to receive up to $245.0 million in potential total milestone payments based upon the achievement of certain development, regulatory, first commercial sales and sales milestone events for the SYNGAP1 program, assuming each milestone were achieved at least once. For SYNGAP1 licensed products that the Company is co-developing and co-commercializing, the Company will be responsible for 50% of the development and commercialization costs and will receive 50% of the profits from global commercialization. The Company is provided with a co-development and co-commercialization opt out option relating to the SYNGAP1 target indication at the Company’s discretion. Such opt-out would reduce development and commercialization milestones but would provide the Company with royalties on an escalating basis attributable to net sales milestones. As a result of the termination of the Discontinued Acadia Programs, the Company is no longer eligible to receive the milestones for those programs of up to $662.5 million or any royalties related thereto.

Acadia Agreement accounting

At the commencement of the Acadia Agreement, the Company identified three performance obligations consisting of pre-clinical research activities for each of the three targets, SYNGAP1, MECP2, and the undisclosed neurodevelopmental target. The exclusive or co-exclusive licenses granted to Acadia to conduct pre-clinical research activities on each of the three targets, and participation on each of the respective joint research committees were identified as promised services. However, the licenses granted to Acadia and the research activities were determined to be not distinct from each other, and therefore are considered a combined performance obligation for each of the three targets. Participation on each of the joint research committees was determined to be quantitatively and quantitatively immaterial in the context of the arrangement with Acadia.

The Company is recognizing the transaction price for the pre-clinical research activities for each of the three targets over time as the research services are provided. The transfer of control to Acadia occurs over this time period, and in management’s judgment, is the best measure of progress towards satisfying the performance obligation. An input method is used that measures the cost incurred to date in satisfying each of the three research activities in relation to the estimated total projected cost of each of the research activities to fulfill the respective obligations. The cumulative effect of revisions to estimated costs and/or the transaction price to complete the research performance obligations will be recorded in the period in which changes are identified and amounts can be reasonably estimated.

STOK US Equity

STOK · 10-K · period ended 2025-12-31

Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations.

Item 7A. Quantitative and Qualitative Disclosures About Market Risk.

Item 8. Financial Statements and Supplementary Data.

Item 9. Changes in and Disagreements With Accountants on Accounting and Financial Disclosure.

Item 9A. Controls and Procedures.

Item 9B. Other Information.

Item 9C. Disclosure Regarding Foreign Jurisdictions That Prevent Inspections.

Item 10. Directors, Executive Officers and Corporate Governance.

Item 11. Executive Compensation.

Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters.

Item 13. Certain Relationships and Related Transactions, and Director Independence.

Item 14. Principal Accountant Fees and Services.

Item 15. Exhibits, Financial Statement Schedules.

Item 16. Form 10-K Summary

STOK US Equity☆

STOK · 10-K · period ended 2025-12-31

Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations.

Item 7A. Quantitative and Qualitative Disclosures About Market Risk.

Item 8. Financial Statements and Supplementary Data.

Item 9. Changes in and Disagreements With Accountants on Accounting and Financial Disclosure.

Item 9A. Controls and Procedures.

Item 9B. Other Information.

Item 9C. Disclosure Regarding Foreign Jurisdictions That Prevent Inspections.

Item 10. Directors, Executive Officers and Corporate Governance.

Item 11. Executive Compensation.

Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters.

Item 13. Certain Relationships and Related Transactions, and Director Independence.

Item 14. Principal Accountant Fees and Services.

Item 15. Exhibits, Financial Statement Schedules.

Item 16. Form 10-K Summary

STOK US Equity