Stoke Therapeutics, Inc.

Previous wording

You should read the following discussion and analysis of our financial condition and consolidated results of operations together with the section entitled “Risk Factors” and our interim consolidated financial statements and related notes appearing elsewhere in this Quarterly Report. Some of the information contained in this discussion and analysis or set forth elsewhere in this Quarterly Report, 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 “Special Note Regarding Forward-Looking Statements” and “Risk Factors” to gain an understanding of the important factors that could cause actual results to differ materially from our forward-looking statements.

Current wording

You should read the following discussion and analysis of our financial condition and consolidated results of operations together with the section entitled “Risk Factors” and our interim unaudited condensed consolidated financial statements and related notes appearing elsewhere in this Quarterly Report. Some of the information contained in this discussion and analysis or set forth elsewhere in this Quarterly Report, 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 “Forward-Looking Statements” and “Risk Factors” to gain an understanding of the important factors that could cause actual results to differ materially from our forward-looking statements.

Previous wording

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.

Current wording

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 protein upregulation platform, we are developing antisense oligonucleotides (“ASOs”) to selectively restore protein levels.

Previous wording

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 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.

Current wording

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.

Previous wording

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. The trial initiated in August, and we plan to enroll our first patient in the Phase 1 study in the second half of 2025.

Current wording

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.

Previous wording

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”).

Current wording

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 a Controlled Equity Offering Sales Agreement (the “Sales Agreement”). We do not intend to make any further offers or sales of our common stock pursuant to the Sales Agreement under the 2025 Registration Statement.

Previous wording

In October 2024, we filed an automatic universal Shelf Registration statement on Form S-3 (the “2024 Registration Statement”) with the SEC. The 2024 Registration Statement contains two prospectuses: a base prospectus, which covers the offering, issuance and sale by us 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. Following the filing of our Annual Report on Form 10-K for the year ended December 31, 2024 in March 2025, the 2024 Registrations Statement is no longer effective.

Current wording

In March 2026, we filed an automatic universal Shelf Registration Statement on Form S-3 (the “2026 Registration Statement”) with the SEC. The 2026 Registration Statement contains two prospectuses: a base prospectus, which covers the offering, issuance and sale by us 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 our 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. We intend to use the 2026 Registration Statement for any future issuances and sales of common stock.

Previous wording

As of September 30, 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 September 30, 2025, we had not issued or sold any shares pursuant to the 2024 Registration Statement or 2025 Registration Statement. Since September 30, 2025, through the date of the issuance of these consolidated financial statements, we sold approximately 1.8 million shares of our common stock and received $48.7 million, net of commissions, pursuant to the 2025 Registration Statement. We may terminate this at-the-market program at any time, pursuant to its terms.

Current wording

As of March 31, 2026, we had issued approximately 3.2 million shares of common stock pursuant to the 2025 Registration Statement for net proceeds of $87.8 million. In addition, as of March 31, 2026, we had issued approximately 2.6 million shares of common stock pursuant to the Sales Agreement and the 2026 Registration Statement for net proceeds of $80.7 million. We may terminate this at-the-market program under the Sales Agreement at any time, pursuant to its terms.

Previous wording

As of September 30, 2025 and December 31, 2024 we had $328.6 million and $246.7 million, respectively, in cash, cash equivalents and marketable securities.

Current wording

As of March 31, 2026 and December 31, 2025 we had $411.0 million and $390.9 million, respectively, in cash, cash equivalents and marketable securities.

Previous wording

Since inception, we have primarily had operating losses, which are attributable to research and development activities. Our net losses were $38.3 million and $26.4 million for the three months ended September 30, 2025 and 2024, respectively. For the nine months ended September 30, 2025 we had a net income of $51.0 million and for the nine months ended September 30, 2024 we had net losses of $78.5 million. As of September 30, 2025, we had an accumulated deficit of $439.8 million.

Current wording

Since inception, we have had operating losses, the majority of which are attributable to research and development activities. Our net losses were $50.0 million for the three months ended March 31, 2026 and our net income for the three months ended March 31, 2025 was $112.9 million. As of March 31, 2026, we had an accumulated deficit of $547.7 million.

Previous wording

Our primary use of cash is to fund operating expenses, which consist primarily of research and development expenditures, and to a lesser extent, sales, general and administrative expenditures. 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, and capital expenditures 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, as well as hire additional personnel, develop commercial infrastructure, pay fees to outside consultants, lawyers and accountants, and incur increased 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. 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.

Current wording

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.

Previous wording

Based upon our current operating plan, we believe that our cash, cash equivalents, and marketable securities of approximately $328.6 million as of September 30, 2025, will fund operations to mid-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, which we expect will take a number of years. 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.

Current wording

Based upon our current operating plan, we believe that our cash, cash equivalents, and marketable securities of approximately $411.0 million as of March 31, 2026, 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.

Previous wording

Presentations of new clinical data for zorevunersen at medical congresses have provided greater understanding of its disease-modifying potential that is highly differentiated from any currently available treatments. In August 2025, we announced new positive findings from the long-term open-label extension (OLE) studies of zorevunersen in children and adolescents with Dravet syndrome.

Current wording

Presentations of new clinical data for zorevunersen at medical congresses have contributed to greater understanding of its disease-modifying potential that is highly differentiated from any currently available treatments. In May 2026, we announced new findings from four-year longitudinal data from the ongoing Phase 1/2 open-label extension (OLE) studies of zorevunersen in children and adolescents with Dravet syndrome. 93% (75/81) of eligible patients continued treatment in the OLE studies, providing a longitudinal dataset to assess long-term outcomes. As of February 2026, 77% (58/75) of patients remain in these studies.

Previous wording

Exhibit 1: Three Year OLE Seizure Data

Current wording

Exhibit 1: Four Year OLE Seizure Data

Previous wording

Exhibit 2: Three Year Vineland OLE Cognition and Behavior

Current wording

Exhibit 2: Year Four Vineland OLE Cognition and Behavior

Previous wording

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 have 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 to 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.

Current wording

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 MECP2 and the neurodevelopmental target, we granted Acadia worldwide, exclusive licenses to develop and commercialize licensed products for such targets. In September 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.

Previous wording

Pursuant to the terms of the agreement, we received an upfront payment of $60.0 million from Acadia. Acadia agreed to fund the research to identify potential licensed products 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 with 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, the Company is no longer eligible to receive the milestones for those programs of up to $662.5 million or any royalties related thereto.

Current wording

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.

Previous wording

For the nine months ended, September 30, 2025, we recognized revenue related to the Acadia collaboration of $20.7 million.

Current wording

For the three months ended March 31, 2026, we recognized revenue related to the Acadia collaboration of $2.2 million and for the three months ended March 31, 2025, we recognized revenue related to the Acadia collaboration of $6.1 million.

Previous wording

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. Together with Biogen, we share global development costs based on an agreed budget. We are responsible for 70.0% of these development costs and Biogen is responsible for the remaining 30.0% of these development costs.

Current wording

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.

Previous wording

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. Royalties payable under the Agreement are subject to standard royalty reductions.

Current wording

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 March 31, 2026, no milestones have been met. Royalties payable under the Biogen Agreement are subject to standard royalty reductions.

Previous wording

For the nine months ended, September 30, 2025, we recognized revenue related to the Biogen collaboration of $162.3 million.

Current wording

For the three months ended March 31, 2026, we recognized revenue related to the Biogen collaboration of $4.0 million and for the three months ended March 31, 2025, we recognized revenue related to the Biogen collaboration of $152.5 million.

Previous wording

See Note 7—License and Collaboration Agreementsof the notes to our unaudited consolidated financial statements included elsewhere in this Quarterly Report on Form 10-Q.

Current wording

See Note 7—License and Collaboration Agreementsof the notes to our unaudited condensed consolidated financial statements included elsewhere in this Quarterly Report on Form 10-Q.

Previous wording

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.

Current wording

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 cannot predict with certainty the ultimate duration and total completion costs of our research and development projects or the timing and extent of any revenue we may generate from the commercialization and sale of any of our product candidates.

Previous wording

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:

Current wording

Because of the numerous risks and uncertainties associated with product development, we cannot predict with certainty the ultimate duration and total completion costs of current or future preclinical studies and clinical trials or the timing and extent of any revenues we may generate 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:

Previous wording

Revenue for the three months ended September 30, 2025 was $10.6 million compared to $4.9 million for the three months ended September 30, 2024, an increase of $5.7 million. Revenue is generated from satisfying contractual obligations of the collaboration and licensing agreements with Acadia and Biogen. The increase in revenue is driven by $6.7 million for global development activities as part of the Biogen Agreement offset by a decrease of $1.0 million related to the Acadia Agreement.

Current wording

Revenue for the three months ended March 31, 2026 was $6.2 million compared to $158.6 million for the three months ended March 31, 2025, a decrease of $152.4 million. Revenue is generated from satisfying contractual obligations of the collaboration and licensing agreements with Acadia and Biogen. The decrease in revenue is primarily driven by the recognition of $150.8 million related to the IP license performance obligation during the year ended December 31, 2025.

Previous wording

Research and development expenses were $37.7 million for the three months ended September 30, 2025 as compared to $22.2 million for the three months ended September 30, 2024, an increase of $15.5 million. The table below summarizes our research and development expenses (in thousands):

Current wording

Research and development expenses were $39.7 million for the three months ended March 31, 2026 as compared to $32.7 million for the three months ended March 31, 2025, an increase of $7.0 million. The table below summarizes our research and development expenses (in thousands):

Previous wording

The increase in research and development expenses was attributable to an increase of $3.2 million in personnel-related expenses, $11.7 million in expenses related to our zorevunersen program, $0.2 million in expenses related to our ADOA program, both of which are comprised of third-party services and scientific consulting fees, an increase of $0.2 million in external third-party expenses related to SYNGAP1 and MECP2, and an increase of $0.2 in facilities and other non-program related costs.

Current wording

The increase in research and development expenses was attributable to an increase of $5.1 million in personnel-related expenses, $0.7 million in expenses related to our ADOA program, which are comprised of third-party services and scientific consulting fees, an increase of $0.4 million related to SYNGAP1 offset by a decrease of $0.1 million related to MECP2 in external third-party expenses related to SYNGAP1 and MECP2, and an increase of $1.4 million in other non-program related costs offset by a decrease of $0.5 million in expenses related to our zorevunersen program.

Previous wording

Sales, general and administrative expenses were $16.0 million for the three months ended September 30, 2025 as compared to $12.7 million for the three months ended September 30, 2024. The increase of $3.3 million in sales, general and administrative expenses was attributable to an increase of $2.5 million in personnel expenses and an increase $0.8 million in facilities and other sales, general and administrative costs.

Current wording

Sales, general and administrative expenses were $20.0 million for the three months ended March 31, 2026 as compared to $14.7 million for the three months ended March 31, 2025. The increase of $5.3 million in sales, general and administrative expenses was attributable to an increase of $3.4 million in facilities and other sales, general and administrative costs for commercial readiness, and $1.9 million in personnel-related expenses.

Previous wording

Under U.S. GAAP, the effects of changes in tax laws are recognized in the period in which the new law is enacted. Accordingly, the impact of the OBBBA was reflected as of September 30, 2025 with the reversal of previously recognized income tax expense for both federal and state.

Current wording

Under U.S. GAAP, the effects of changes in tax laws are recognized in the period in which the new law is enacted. Accordingly, the impact of the OBBBA was reflected as of September 30, 2025 with the reversal of previously recognized income tax expense for both federal and state. There is no impact on the comparable periods presented.

Previous wording

Since our inception through September 30, 2025, our operations have been financed by net proceeds of $836.6 million from the sale of convertible notes payable and our convertible preferred stock, our initial public offering, public offerings of common stock and pre-funded warrants, proceeds from the Sales Agreement and the upfront payments from Acadia and Biogen. As of September 30, 2025, we had $328.6 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. On April 2, 2024, we completed an underwritten public offering of our 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. The common stock and warrants sold resulted in net proceeds of $119.9 million after deducting underwriting discounts, commissions and offering costs. No pre-funded warrants have been exercised.

Current wording

Since our inception through March 31, 2026, our operations have been financed by net proceeds of $1.0 billion from the sale of convertible notes payable and our convertible preferred stock, our initial public offering, public offerings of common stock and pre-funded warrants, proceeds from the Sales Agreement and the upfront payments from Acadia and Biogen. As of March 31, 2026, we had $411.0 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. On April 2, 2024, we completed an underwritten public offering of our 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. The common stock and warrants sold resulted in net proceeds of $119.9 million after deducting underwriting discounts, commissions and offering costs. No pre-funded warrants have been exercised.

Previous wording

We have primarily incurred losses since our inception in June 2014 and, as of September 30, 2025, we had an accumulated deficit of $439.8 million. Our primary use of cash is to fund operating expenses, which consist primarily of research and development expenditures, and to a lesser extent, sales, general and administrative expenditures. 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.

Current wording

We have primarily incurred losses since our inception in June 2014 and, as of March 31, 2026, we had an accumulated deficit of $547.7 million. Our primary use of cash is to fund operating expenses, which consist primarily of research and development expenditures, and to a lesser extent, sales, general and administrative expenditures. 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.

Previous wording

Based upon our current operating plan, we believe that our cash, cash equivalents, and marketable securities of approximately $328.6 million as of September 30, 2025, will fund operations to mid-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.

Current wording

Based upon our current operating plan, we believe that our cash, cash equivalents, and marketable securities of approximately $411.0 million as of March 31, 2026, 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.

Previous wording

During the nine months ended September 30, 2024, cash used in operating activities was $63.7 million. This was primarily attributable to a net loss of $78.5 million, a net change of $8.0 million in our net operating assets and liabilities, offset by non-cash charges of $22.8 million for stock-based compensation, depreciation, amortization and accretion of marketable securities, and a reduction in the carrying amount of right of use assets.

Current wording

During the three months ended March 31, 2026, cash used in operating activities was $60.6 million. This was attributable to a net loss of $50.0 million, a net change of $20.1 million in our net operating assets and liabilities offset by non-cash charges of $9.5 million for stock-based compensation, depreciation, amortization and accretion of marketable securities, and a reduction in the carrying amount of right of use assets.

Previous wording

During the nine months ended September 30, 2025, cash provided by operating activities was $76.0 million. This was attributable to a net income of $51.0 million, a net change of $0.6 million in our net operating assets and liabilities and non-cash charges of $25.6 million for stock-based compensation, depreciation, amortization and accretion of marketable securities, and a reduction in the carrying amount of right of use assets.

Current wording

During the three months ended March 31, 2025, cash provided by operating activities was $131.8 million. This was primarily attributable to a net income of $112.9 million, a net change of $11.5 million in our net operating assets and liabilities and non-cash charges of $7.3 million for stock-based compensation, depreciation, amortization and accretion of marketable securities, and a reduction in the carrying amount of right of use assets.

Previous wording

Our investing activities during the nine months ended September 30, 2025 consisted primarily of $224.5 million of purchases of marketable securities and $0.5 million of purchases of property plant and equipment offset by $99.2 million from the sales of marketable securities.

Current wording

Our investing activities during the three months ended March 31, 2026 consisted primarily of $60.9 million from the maturity of marketable securities offset by $9.9 million of purchases of marketable securities and $0.4 million of purchases of property plant and equipment.

Previous wording

Our investing activities during the nine months ended September 30, 2024 consisted primarily of $138.1 million of purchases of marketable securities offset by $30.0 million from the sales of marketable securities.

Current wording

Our investing activities during the three months ended March 31, 2025 consisted primarily of $32.8 million from the maturity of marketable securities offset by $19.0 million of purchases of marketable securities.

Previous wording

Our financing activities during the nine months ended September 30, 2024 consisted of $119.9 million of net proceeds from a follow-on offering, $9.0 million of net proceeds from the controlled equity offering sales agreement, $1.2 million from the exercise of stock options and $0.5 million in proceeds from our ESPP.

Current wording

Our financing activities during the three months ended March 31, 2026 consisted primarily of $80.7 million in proceeds from the controlled equity offering sales agreement, $3.2 million from the exercise of stock options and $0.5 million in proceeds from our Employee Stock Purchase Plan (the “ESPP”).

Previous wording

Our financing activities during the nine months ended September 30, 2025 consisted of $4.0 million from the exercise of stock options and $1.0 million in proceeds from our Employee Stock Purchase Plan (the “ESPP”).

Current wording

Our financing activities during the three months ended March 31, 2025 consisted of $1.0 million from the exercise of stock options and $0.4 million in proceeds from the ESPP.

Previous wording

Our commitments primarily consist of obligations under our agreement with the University of Southampton. As of September 30, 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 Note 6—Commitments and Contingencies of the notes to our consolidated financial statements included elsewhere in this Quarterly Report on Form 10-Q.

Current wording

Our commitments primarily consist of obligations under our agreement with the University of Southampton. As of March 31, 2026, 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 Note 6—Commitments and Contingencies of the notes to our condensed consolidated financial statements included elsewhere in this Quarterly Report on Form 10-Q.

Previous wording

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.

Current wording

Our management’s discussion and analysis of our financial condition and results of operations is based on our condensed consolidated financial statements, which have been prepared in accordance with generally accepted accounting principles (“GAAP”). The preparation of these condensed 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 condensed 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.

Previous wording

There have been no significant changes in our critical accounting policies and estimates as compared to the critical accounting policies and estimates disclosed in the section titled “Management’s Discussion and Analysis of Financial Condition and Operations” included in our Annual Report on Form 10-K filed with the SEC on March 18, 2025.

Current wording

There have been no significant changes in our critical accounting policies and estimates as compared to the critical accounting policies and estimates disclosed in the section titled “Management’s Discussion and Analysis of Financial Condition and Results of Operations” included in our Annual Report on Form 10-K filed with the SEC on March 16, 2026.