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

The following discussion and analysis is meant to provide material information relevant to an assessment of the financial condition and results of operations of our company, including an evaluation of the amounts and certainty of cash flows from operations and from outside resources, so as to allow investors to better view our company from management’s perspective. The following discussion of our financial condition and results of operations should be read in conjunction with our financial statements and the notes to those financial statements appearing elsewhere in this Annual Report on Form 10-K. This discussion contains forward-looking statements that involve significant risks and uncertainties. As a result of many factors, such as those set forth in Part I, Item 1A. Risk Factors, of this Annual Report on Form 10-K, our actual results may differ materially from those anticipated in these forward-looking statements.

We are a global biopharmaceutical company dedicated to the discovery, development and commercialization of clinically differentiated medicines for children and adults living with rare disorders. We are advancing a robust and diversified pipeline of transformative medicines as part of our mission to provide access to best-in-class treatments for patients with unmet medical needs. Our strategy is to leverage our scientific expertise and global commercial infrastructure to optimize value for our patients and other stakeholders. We believe that this allows us to maximize value for all of our stakeholders. We have a diversified therapeutic portfolio that includes several commercial products and product candidates in various stages of development, including clinical, pre-clinical and research and discovery stages, focused on the development of new treatments for multiple therapeutic areas for rare diseases relating to neurology and metabolism.

We have developed SephienceTM (sepiapterin), a product for the treatment of phenylketonuria, or PKU, a rare inherited metabolic disease characterized by the body’s inability to break down an essential amino acid called phenylalanine, and which can result in neurological and other symptoms. In June 2025, Sephience was granted marketing authorization by the European Commission, or EC, for the treatment of children and adults living with PKU within the European Economic

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Area, or EEA. In July 2025, Sephience was approved by the U.S. Food and Drug Administration, or FDA, for the treatment of pediatric and adult patients living with PKU in the United States age one month and above. In December 2025, Sephience was approved by the Japanese Ministry of Health, Labor and Welfare, or MHLW, for the treatment of children and adults living with PKU. In February 2026, Sephience was approved by ANVISA, the Brazilian health regulatory authority, for the treatment of children and adults living with PKU in Brazil. Sephience is also approved in additional geographies. During the year ended December 31, 2025, we recognized $111.2 million in net product revenues for Sephience.

We have two products, TranslarnaTM (ataluren) and Emflaza® (deflazacort), for the treatment of Duchenne muscular dystrophy, or DMD, a rare, life threatening disorder. While Translarna previously had conditional approval in the EEA, in March 2025, the European Commission, or EC, adopted the negative opinion of the Committee of Medicinal Products for Human Use, or CHMP, of the European Medicines Agency, or EMA, to not renew the conditional marketing authorization of Translarna for the treatment of nmDMD. However, the EC indicated that individual countries within the European Union, or EU, can leverage Articles 117(3) and 5(1) of the EU Directive 2001/83 to allow continued commercial use of Translarna. Translarna has marketing authorization in additional geographies outside of the EEA, though the EC adoption of the CHMP negative opinion and the withdrawal of the Translarna NDA in the United States may affect future reauthorizations. During the year ended December 31, 2025, we recognized $235.3 million in net product revenues for Translarna. Emflaza is approved in the United States for the treatment of DMD in patients two years and older. During the year ended December 31, 2025, we recognized $146.4 million in net product revenues for Emflaza.

Each country, including each member state of the EEA, has its own pricing and reimbursement regulations. In order to commence commercial sale of product pursuant to our Sephience marketing authorization in any particular country in the EEA, we must finalize pricing and reimbursement negotiations with the applicable government body in such country. As a result, our commercial launch will continue to be on a country-by-country basis. We also have made, and expect to continue to make, product available under early access programs, or EAP programs, or similar styled programs both in countries in the EEA and other territories. Our ability to negotiate, secure and maintain reimbursement for product under commercial and EAP programs can be subject to challenge in any particular country and can also be affected by political, economic and regulatory developments in such country.

Translarna is an investigational new drug in the United States. During the first quarter of 2017, we filed an NDA for Translarna for the treatment of nmDMD over protest with the FDA. In October 2017, the Office of Drug Evaluation I of the FDA issued a complete response letter for the NDA, stating that it was unable to approve the application in its current form. In response, we filed a formal dispute resolution request with the Office of New Drugs of the FDA. In February 2018, the Office of New Drugs of the FDA denied our appeal of the complete response letter. In its response, the Office of New Drugs recommended a possible path forward for our ataluren NDA submission based on the accelerated approval pathway. We followed the FDA’s recommendation and collected, using newer technologies via procedures and methods that we designed in a new study, Study 045, and announced the results of Study 045 in February 2021. Study 045 did not meet its pre-specified primary endpoint. In June 2022, we announced top-line results from the placebo-controlled trial of Study 041, which was our 18 months, placebo-controlled trial, followed by an 18 months open label extension, of Translarna in the treatment of ambulatory patients with nmDMD aged five years or older. Following this announcement, we submitted a meeting request to the FDA to gain clarity on the regulatory pathway for a potential re-submission of an NDA for Translarna. The FDA provided initial written feedback that Study 041 does not provide substantial evidence of effectiveness to support NDA re-submission. We held a Type C meeting with the FDA in the fourth quarter of 2023 to discuss the totality of Translarna data. Based on feedback from the FDA, we re-submitted the NDA in July 2024, based on the results from Study 041 and from our international drug registry study for nmDMD patients receiving Translarna. In October 2024, the FDA accepted for review the resubmission of the NDA for Translarna for the treatment of nmDMD. Following feedback from FDA at the end of January 2026, we decided to withdraw the NDA resubmission for Translarna. Further development of Translarna for the treatment of nmDMD in the United States is not planned.

With respect to Emflaza, we have previously relied on Emflaza’s seven-year marketing exclusivity period in the United States for its approved indications under the provisions of the Orphan Drug Act of 1983, or the Orphan Drug Act, when commercializing Emflaza for the treatment of DMD in patients five years and older, which expired in February 2024. With the expiration of this orphan drug exclusivity, we have seen an increase in competition from generics, which has, and we expect will continue to have, a negative impact on Emflaza net product revenue. Emflaza’s orphan drug

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exclusivity related to the treatment of DMD in patients two years of age to less than five expires in June 2026. See “Item 1. Business-Government Regulation” for further discussion with respect to marketing protection we rely on.

Upstaza/Kebilidi is a gene therapy for the treatment of Aromatic L Amino Decarboxylase, or AADC, deficiency, a rare central nervous system, or CNS, disorder arising from reductions in the enzyme AADC that results from mutations in the dopa decarboxylase gene. In July 2022, the EC approved Upstaza for the treatment of AADC deficiency for patients 18 months and older within the EEA. In November 2022, the Medicines and Healthcare Products Regulatory Agency approved Upstaza for the treatment of AADC deficiency for patients 18 months and older within the United Kingdom. In November 2024, the FDA granted accelerated approval of our gene therapy for the treatment of children and adults with AADC deficiency, which is marketed with the brand name Kebilidi in the United States. We are obligated to complete certain post-marketing requirements in connection with the FDA's approval, including clinical safety studies.

We hold the rights for the commercialization of Tegsedi and Waylivra for the treatment of rare diseases in countries in Latin America and the Caribbean pursuant to a Collaboration and License Agreement, or the Tegsedi-Waylivra Agreement, dated August 1, 2018, by and between us and Akcea Therapeutics, Inc., or Akcea, a subsidiary of Ionis Pharmaceuticals, Inc. Tegsedi has received marketing authorization in the United States, EU, and Brazil for the treatment of stage 1 or stage 2 polyneuropathy in adult patients with hereditary transthyretin amyloidosis, or hATTR amyloidosis. In August 2021, ANVISA, the Brazilian health regulatory authority, approved Waylivra as the first treatment for familial chylomicronemia syndrome, or FCS, in Brazil. In December 2022, ANVISA approved Waylivra for the treatment of familial partial lipodystrophy, or FPL. Waylivra has also received marketing authorization in the EU for the treatment of FCS.

We also have a spinal muscular atrophy, or SMA, collaboration with F. Hoffman La Roche Ltd. and Hoffman La Roche Inc., which we refer to collectively as Roche, and the Spinal Muscular Atrophy Foundation, or SMA Foundation. The SMA program has one approved product, Evrysdi® (risdiplam), which was approved by the FDA in August 2020 for the treatment of SMA in adults and children two months and older and by the EC in March 2021 for the treatment of 5q SMA in patients two months and older with a clinical diagnosis of SMA Type 1, Type 2 or Type 3 or with one to four SMN2 copies. Evrysdi has also received marketing authorization for the treatment of SMA in over 100 countries. In May 2022, the FDA approved a label expansion for Evrysdi to include infants under two months old with SMA. In August 2023, the EC approved an extension of the Evrysdi marketing authorization to include infants under two months old in the EU.

In addition to our SMA program, our splicing platform also includes votoplam, which is being developed for the treatment of Huntington’s disease, or HD. We announced the results from our Phase 1 study of votoplam in healthy volunteers in September 2021 demonstrating dose-dependent lowering of huntingtin messenger ribonucleic acid and protein levels, that votoplam efficiently crosses blood brain barrier at significant levels and that votoplam was well tolerated. We initiated a Phase 2 study of votoplam for the treatment of HD in the first quarter of 2022, which consisted of an initial 12-week placebo-controlled phase focused on safety, pharmacology and pharmacodynamic effects followed by a nine-month placebo-controlled phase focused on votoplam biomarker effect. In September 2024, the FDA granted Fast Track designation to the votoplam program for the treatment of HD. In November 2024, we entered into a License and Collaboration Agreement with Novartis Pharmaceuticals Corporation, or Novartis, relating to our votoplam program, or the Novartis Agreement, which included related molecules. While Novartis has taken over responsibility for the further development of the votoplam program, we continue to collaborate with Novartis on next steps. In May 2025, we announced that the Phase 2 study of votoplam met its primary endpoints of blood HTT lowering and safety. The results on the full study population are consistent with the previously reported evidence of dose-dependent HTT lowering, favorable safety profile and early signals of dose-dependent clinical effect at 12 months in Stage 2 patients. In addition, at 24 months of treatment, there were continued trends of dose-dependent favorable clinical effect relative to a propensity-matched natural history cohort as well as dose-dependent NfL lowering. In the fourth quarter of 2025, an End-of-Phase 2 meeting was held with FDA, and we reached alignment on design of a global Phase 3 clinical trial, which we expect that Novartis will initiate in the first half of 2026. This trial could serve as the confirmatory study in the context of Accelerated Approval, or as a registration trial. We also expect to have results from the Phase 2 PIVOT-HD extension study of votoplam in the first half of 2026, once all participants cross the 24-month time point.

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Our inflammation and ferroptosis platform consists of small molecule compounds that target oxidoreductase enzymes that regulate oxidative stress and inflammatory pathways central to the pathology of a number of CNS and non-CNS diseases. The most advanced molecule in our inflammation and ferroptosis platform is vatiquinone. We announced topline results from a registration-directed Phase 3 trial of vatiquinone in children and young adults with Friedreich’s ataxia, or FA, called MOVE-FA, in May 2023. While the trial did not meet its primary endpoint, vatiquinone treatment did demonstrate significant benefit on key disease subscales, including the upright stability subscale, as well as on other disease relevant endpoints.In October 2024, we announced that the pre-specified endpoint for two different FA long-term extension studies was met, with statistically significant evidence of durable treatment benefit on disease progression. In December 2024, we submitted an NDA to the FDA for vatiquinone for the treatment of children and adults living with FA. In August 2025, the FDA issued a complete response letter related to the NDA stating that substantial evidence of efficacy was not demonstrated for vatiquinone and that an additional adequate and well-controlled study would be needed to support NDA resubmission. We met with the FDA in the fourth quarter of 2025 to discuss the vatiquinone development program. FDA suggested an additional study be conducted to support NDA resubmission. FDA stated in the meeting minutes that this study could be an open label study with a natural history control group. We plan to meet with FDA in the second quarter of 2026 to discuss the design of this new study.

In addition, we have a pipeline of product candidates and discovery programs that are in early clinical, pre-clinical and research and development stages focused on the development of new treatments for multiple therapeutic areas for rare diseases.

Overview—Funding

The success of our products and any other product candidates we may develop depends largely on obtaining and maintaining reimbursement from governments and third-party insurers. During 2025, our revenues were primarily generated from sales of Sephience for the treatment of PKU in the U.S. and EEA, Translarna for the treatment of nmDMD in countries where we were able to obtain acceptable commercial pricing and reimbursement terms and in select countries where we are permitted to distribute Translarna under our EAP programs or through similar styled programs, and from sales of Emflaza for the treatment of DMD in the United States. There is a substantial risk that as a result of the EC’s adoption of the CHMP’s negative opinion we will lose a significant portion of our ability to generate revenue from sales of Translarna in the EEA. We also generated revenue from sales of Upstaza/Kebilidi for the treatment of AADC deficiency in the EEA and in the U.S., and have recognized revenue associated with milestone and royalty payments from Roche pursuant to a License and Collaboration Agreement, or the SMA License Agreement, by and among us, Roche and, for the limited purposes set forth therein, the SMA Foundation, under our SMA program and we have recognized license revenues related to performance obligations completed pursuant to the Novartis Agreement.

In August 2019, we entered into an At the Market Offering Sales Agreement, or the Sales Agreement, with Cantor Fitzgerald and RBC Capital Markets, LLC, or together, the Sales Agents, pursuant to which, we may offer and sell shares of our common stock, having an aggregate offering price of up to $125.0 million from time to time through the Sales Agents by any method that is deemed to be an “at the market offering” as defined in Rule 415(a)(4) promulgated under the Securities Act of 1933, as amended, or the Securities Act. We did not issue or sell any shares of common stock pursuant to the Sales Agreement during the years ended December 31, 2025, 2024 and 2023. The remaining shares of our common stock available to be issued and sold, under the Sales Agreement, have an aggregate offering price of up to $93.0 million as of December 31, 2025.

In September 2019, we issued $287.5 million aggregate principal amount of 1.50% convertible senior notes due September 15, 2026, or the 2026 Convertible Notes, which included an option to purchase up to an additional $37.5 million in aggregate principal amount of the 2026 Convertible Notes, which was exercised in full by the initial purchasers. We received net proceeds of $279.3 million after deducting the initial purchasers’ discounts and commissions and the offering expenses payable by us. See “Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations—Liquidity and capital resources—Sources of liquidity” for additional information.

In July 2020, we entered into a Royalty Purchase Agreement, or the Original Royalty Purchase Agreement, with RPI Intermediate Finance Trust, or RPI, and, for the limited purposes set forth in the agreement, Royalty Pharma plc. Pursuant to the Original Royalty Purchase Agreement, we sold to RPI 42.933%, or the Original Assigned Royalty Rights, of the

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Royalty (as defined below) for $650.0 million. At that time, we retained a 57.067% interest in the Royalty and all economic rights to receive the remaining potential regulatory and sales milestone payments under the SMA License Agreement.

In June 2021, we filed a Certificate of Amendment to our Restated Certificate of Incorporation, which increased the number of authorized shares of our common stock from 125,000,000 to 250,000,000 shares.

In October 2022, we entered into the Credit Agreement, dated October 27, 2022, by and among us and certain of our subsidiaries from time to time party thereto, as guarantors, or, collectively with us, the Loan Parties, funds and other affiliated entities advised or managed by Blackstone Life Sciences and Blackstone Credit, or collectively, Blackstone, as lenders, together with their permitted assignees, the Lenders, and Wilmington Trust, National Association, as the administrative agent for the Lenders, or the Blackstone Credit Agreement, which we terminated in October 2023. In connection with the termination of the Blackstone Credit Agreement, we repaid outstanding principal of $300.0 million, accrued interest of $2.1 million, an additional $82.0 million in prepayment premiums, exit fees, and creditor expenses, and $0.2 million in legal fees. We recorded a loss on the extinguishment of debt of $92.7 million which is included on the statement of operations for the period ended December 31, 2023. The loss on extinguishment of debt consisted of $82.0 million in prepayment premiums, exit fees, and creditor expenses and debt issuance costs of $10.7 million. All liens and security interests securing the loans made pursuant to the Blackstone Credit Agreement were released upon termination.

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In June 2024, we entered into an amendment with Royalty Pharma Investments 2019 ICAV, or Royalty Pharma, and Royalty Pharma plc, to the Amended and Restated Royalty Purchase Agreement, dated October 18, 2023, or the A&R Royalty Purchase Agreement, which amends and restated in its entirety the Original Royalty Purchase Agreement, and we exercised our first put option in exchange for $241.8 million in cash consideration. In December 2025, we, Royalty Pharma, and, for the limited purposes set forth in Amendment No. 2 (as defined below), Royalty Pharma plc, entered into an Amendment No. 2 to Amended and Restated Royalty Purchase Agreement, or Amendment No. 2, which amends that certain A&R Royalty Purchase Agreement, as amended. Under Amendment No. 2, we sold to Royalty Pharma a certain portion of our right to receive sales-based royalty payments on worldwide net sales of Roche’s Evrysdi® (risdiplam) product and any other product developed pursuant to the License and Collaboration Agreement, dated as of November 23, 2011, by and among us, F. Hoffman-La Roche Ltd, Hoffman-La Roche Inc., together with F. Hoffman-La Roche Ltd, Roche, and, for the limited purposes set forth therein, the Spinal Muscular Atrophy Foundation, such payments, the Royalty. Pursuant to Amendment No. 2, on December 29, 2025, we sold to Royalty Pharma its retained interest in the Royalty in exchange for $240.0 million in upfront cash consideration, and three potential additional cash purchase price payments of $20.0 million each conditioned upon receipt by Royalty Pharma of more than $347.0 million of Assigned Royalty Payments (as defined in the A&R Royalty Purchase Agreement) in respect of Calendar Year Net Sales (as defined in the A&R Royalty Purchase Agreement) arising in 2027, $363.0 million of Assigned Royalty Payments in respect of Calendar Year Net Sales arising in 2028, and $379.0 million of Assigned Royalty Payments in respect of Calendar Year Net Sales arising in 2029, respectively. The retained interest sold by us to Royalty Pharma pursuant to the Amendment No. 2 is equal to 9.5111% of the Royalty before the 2020 Assigned Royalty Cap (as defined in the A&R Royalty Purchase Agreement) has been met, and 16.6666% of the Royalty from and after such time as the 2020 Assigned Royalty Cap has been met. As a result of the sale, Royalty Pharma owns 100% of the Royalty and we own 0% of the Royalty. See “Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations—Liquidity and capital resources—Sources of Liquidity” for additional information.

In November 2024, we entered into the Novartis Agreement relating to our votoplam HD program which includes related molecules. Novartis is responsible for all other development of licensed compounds and licensed products and the manufacture and commercialization of licensed compounds and licensed products worldwide. While Novartis has taken over responsibility for the further development of the votoplam program, we continue to collaborate with Novartis on next steps. Under the Novartis Agreement, and upon the closing of the transaction contemplated by the Novartis Agreement in January 2025, we received an upfront payment of $1.0 billion on the effective date and can receive up to $1.9 billion in development, regulatory and sales milestones, a 40% share of U.S. profits and losses, and tiered double-digit royalties on ex-U.S. sales. See “Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations—Liquidity and capital resources—Sources of Liquidity” for additional information.

We have financed our operations to date primarily through the private offerings of convertible senior notes, public and “at the market offerings” of common stock, proceeds from royalty purchase agreements, private placements of our

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convertible preferred stock and common stock, collaborations, bank and institutional lender debt, other convertible debt, grant funding and clinical trial support from governmental and philanthropic organizations and patient advocacy groups in the disease areas addressed by our product candidates. We have relied on revenue generated from net sales of our products. We have also relied on revenue associated with milestone and royalty payments from Roche pursuant to the SMA License Agreement under our SMA program and license revenues related to performance obligations completed pursuant to the Novartis Agreement.

As of December 31, 2025, we had an accumulated deficit of $2,964.2 million. We had a net income of $682.6 million for the year ended December 31, 2025, and a net loss of $363.3 million and a net loss of $626.6 million for the fiscal years ended December 31, 2024 and 2023, respectively.

We anticipate that we will continue to incur significant expenses in connection with our commercialization efforts in the United States, the EEA, Latin America, Japan and other territories, including expenses related to our commercial infrastructure and corresponding sales and marketing, legal and regulatory, and distribution and manufacturing undertakings as well as administrative and employee-based expenses. In addition to the foregoing, we expect to continue to incur significant costs in connection with ongoing, planned and potential future clinical trials and studies for our splicing and inflammation and ferroptosis programs as well as studies in our products for maintaining authorizations, label extensions and additional indications. In August 2025, the FDA issued a complete response letter related to the NDA stating that substantial evidence of efficacy was not demonstrated for vatiquinone and that an additional adequate and well-controlled study would be needed to support NDA resubmission. We met with the FDA in the fourth quarter of 2025 to discuss the vatiquinone development program. FDA suggested an additional study be conducted to support NDA resubmission. FDA stated in the meeting minutes that this study could be an open label study with a natural history control group. We plan to meet with FDA in the second quarter of 2026 to discuss the design of this new study.

We may seek to expand and diversify our product pipeline through opportunistically in-licensing or acquiring the rights to products, product candidates or technologies and we may incur expenses, including with respect to transaction costs, subsequent development costs or any upfront, milestone or other payments or other financial obligations associated with any such transaction, which would increase our future capital requirements.

With respect to our outstanding 2026 Convertible Notes, cash interest payments are payable on a semi-annual basis in arrears, which will require total funding of $4.3 million annually. These notes are currently convertible and will mature and become due and payable on September 15, 2026 unless earlier redeemed or converted.

In June 2025, Sephience was granted marketing authorization by the EC for the treatment of children and adults living with PKU. Pursuant to the Censa Merger Agreement, the approval triggered a $25.0 million milestone payable to the former Censa securityholders. In July 2025, Sephience was granted FDA approval for the treatment of children and adults living with PKU. Pursuant to the Censa Merger Agreement, the approval triggered a $32.5 million milestone payment to the former Censa securityholders. As of December 31, 2025, we have paid to the former Censa securityholders all potential regulatory milestones relating to Sephience.

We will need to generate significant revenues to achieve and sustain profitability, and we may never do so. Accordingly, we may need to obtain substantial additional funding in connection with our continuing operations. Adequate additional financing may not be available to us on acceptable terms, or at all. If we are unable to raise capital when needed or on attractive terms, we could be forced to delay, reduce or eliminate our research and development programs or our commercialization efforts.

Financial operations overview

Revenues

To date, our net product revenues have consisted primarily of sales of Translarna for the treatment of nmDMD in territories outside of the United States, and sales of Emflaza for the treatment of DMD in the United States. Beginning in the second half of 2025, our net product revenues also includes Sephience for the treatment of PKU. There is a substantial risk that as a result of the EC’s adoption of the CHMP’s negative opinion we will lose a significant portion of our ability

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to generate revenue from sales of Translarna in the EEA. Our process for recognizing revenue is described below under “Critical accounting policies and significant judgments and estimates—Revenue recognition”.

Roche and the SMA Foundation Collaboration. In November 2011, we entered into the SMA License Agreement pursuant to which we are collaborating with Roche and the SMA Foundation to further develop and commercialize compounds identified under our SMA program with the SMA Foundation. The research component of this agreement terminated effective December 31, 2014. We are eligible to receive additional payments from Roche if specified events are achieved with respect to each licensed product, including up to $135.0 million in research and development event milestones, up to $325.0 million in sales milestones upon achievement of specified sales events, and up to double digit royalties on worldwide annual net sales of a commercial product. As of December 31, 2025, we had recognized a total of $310.0 million in milestone payments and $789.8 million in royalties on net sales pursuant to the SMA License Agreement. As of December 31, 2025, there are no remaining research and development event milestones that we can receive. The remaining potential sales milestones as of December 31, 2025 are $150.0 million upon achievement of certain sales events.

In June 2024, we entered into an amendment to the A&R Royalty Purchase Agreement, and we exercised our first put option in exchange for $241.8 million in cash consideration. Pursuant to the A&R Royalty Purchase Agreement, Royalty Pharma has paid to us aggregate cash consideration of $1.9 billion (less Royalty payments received by us with respect to the Assigned Royalty Rights) in exchange for 90.49% of the Royalty, which was to be reduced to 83.33% of the Royalty after Royalty Pharma receives $1.3 billion in aggregate payments from the Royalty assigned at the closing of the Original Purchase Agreement. In December 2025, we, Royalty Pharma, and, for the limited purposes set forth in Amendment No. 2 (as defined below), Royalty Pharma plc, entered into Amendment No. 2, which amends that certain A&R Royalty Purchase Agreement, as amended. Under Amendment No. 2, we sold to Royalty Pharma a certain portion of our right to receive sales-based royalty payments on worldwide net sales of Roche’s Evrysdi® (risdiplam) product and any other product developed pursuant to the License and Collaboration Agreement, dated as of November 23, 2011, by and among us, Roche, and, for the limited purposes set forth therein, the Spinal Muscular Atrophy Foundation, such payments, the Royalty. Pursuant to Amendment No. 2, on December 29, 2025, we sold to Royalty Pharma its retained interest in the Royalty in exchange for $240.0 million in upfront cash consideration, and three potential additional cash purchase price payments of $20.0 million each conditioned upon receipt by Royalty Pharma of more than $347.0 million of Assigned Royalty Payments (as defined in the A&R Royalty Purchase Agreement) in respect of Calendar Year Net Sales (as defined in the A&R Royalty Purchase Agreement) arising in 2027, $363.0 million of Assigned Royalty Payments in respect of Calendar Year Net Sales arising in 2028, and $379.0 million of Assigned Royalty Payments in respect of Calendar Year Net Sales arising in 2029, respectively. The retained interest sold by us to Royalty Pharma pursuant to the Amendment No. 2 is equal to 9.5111% of the Royalty before the 2020 Assigned Royalty Cap (as defined in the A&R Royalty Purchase Agreement) has been met, and 16.6666% of the Royalty from and after such time as the 2020 Assigned Royalty Cap has been met. As a result of the sale, Royalty Pharma owns 100% of the Royalty and we own 0% of the Royalty.

Novartis Collaboration. On November 27, 2024, we and Novartis entered into the Novartis Agreement relating to our votoplam HD program which includes related molecules. Under the Novartis Agreement, and upon the closing of the transaction contemplated by the Novartis Agreement in January 2025, we received an upfront payment of $1.0 billion on the effective date and can receive up to $1.9 billion in development, regulatory and sales milestones, a 40% share of U.S. profits and losses, and tiered double-digit royalties on ex-U.S. sales. See “Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations—Liquidity and capital resources—Sources of liquidity” for additional information.

Research and development expense

Research and development expenses consist of the costs associated with our research activities, as well as the costs associated with our drug discovery efforts, conducting preclinical studies and clinical trials, manufacturing development efforts and activities related to regulatory filings. Our research and development expenses consist of:

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We use our employee and infrastructure resources across multiple research projects, including our drug development programs. We track expenses related to our clinical programs and certain preclinical programs on a per project basis.

We expect our research and development expenses to fluctuate in connection with our ongoing activities, particularly in connection with our activities for our splicing and inflammation and ferroptosis programs and performance of any post-marketing requirements imposed by regulatory agencies with respect to our products. The timing and amount of these expenses will depend upon the outcome of our ongoing clinical trials and the costs associated with our planned clinical trials. The timing and amount of these expenses will also depend on the costs associated with potential future clinical trials of our products or product candidates and the related expansion of our research and development organization, regulatory requirements, advancement of our preclinical programs, and product and product candidate manufacturing costs. In 2023, as part of our strategic pipeline prioritizations, we decided to discontinue our preclinical and early research programs for our gene therapy and oncology platforms, reducing research and development expenses in these areas.

The following table provides research and development expense for our most advanced principal product development programs, for the years ended December 31, 2025, 2024, and 2023.

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Development. Consists of costs incurred for product candidates following initiation of a clinical trial.

For the year ended December 31, 2025, compared to the years ended December 31, 2024 and 2023, the changes reflect progressing through different phases of studies as we continue to focus our resources on our differentiated, high potential research and development programs. The decrease is primarily due to a decrease relating to Global DMD, Gene Therapy, and Splicing platform, offset by an increase in Sephience related development.

Research. Consists of costs incurred for product candidates before initiation of a clinical trial.

For the year ended December 31, 2025, compared to the years ended December 31, 2024 and 2023, the decrease in research expenses was primarily related to our strategic pipeline prioritization in 2023 where we discontinued several preclinical and early research programs. The decrease also reflects our continued focus of our resources on product candidates approaching approval during the current year periods.

Milestones. Consists of development and regulatory milestone expenses incurred in connection with our collaborative arrangements.

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For the year ended December 31, 2025, compared to the years ended December 31, 2024 and 2023, the changes in milestone expenses primarily related to no milestones expensed in year the ended December 31, 2025, as compared to the achievement of a $15.0 million success-based regulatory milestone for the validation and acceptance of an MMA for Sephience for PKU in May 2024, the achievement of a $25.0 million regulatory milestone for the decision to submit an NDA to the FDA for Sephience for PKU in July 2024, and the achievement of a $25.0 million regulatory milestone for the acceptance of an NDA by the FDA for Sephience for PKU in September 2024, as compared to the achievement of a $30.0 million success-based development milestone for the completion of enrollment of a Phase 3 clinical trial for Sephience for PKU in February 2023.

Payroll, benefits, and share-based stock compensation. Consists of costs incurred for salaries and wages, bonus, payroll taxes, benefits and share-based stock compensation associated with employees involved in research and development activities. Share-based stock compensation may fluctuate from period to period based on factors that are not within our control, such as our stock price on the dates share-based grants are issued.

For the year ended December 31, 2025, compared to the years ended December 31, 2024 and 2023, the change in payroll, benefits, and share-based stock compensation expenses primarily relates to our reduction in workforce in connection with our strategic pipeline prioritization in 2023 and discontinuation of our preclinical and early research programs in our gene therapy platform.

Facilities and other. Consists of indirect costs incurred for the benefit of multiple programs, including information technology, and other facility-based expenses, such as rent expense.

For the year ended December 31, 2025, compared to the years ended December 31, 2024 and 2023, the change in facilities and other expenses primarily related to decreases in facility-based expenses at our facility in Hopewell Township, New Jersey as a result of an amendment and restatement of our lease for such facility and at our facility in Warren, New Jersey as a result of an amendment to our lease for such facility in the year ended December 31, 2024.

The successful development of our products and product candidates is highly uncertain. This is due to the numerous risks and uncertainties associated with developing drugs, including the uncertainty of:

● clinical trial results;

● the terms and timing of regulatory approvals; and

A change in the outcome of any of these variables with respect to the development of our products or product candidates could mean a significant change in the costs and timing associated with the development of those products or product candidates. For example, if the EMA or the FDA or other regulatory authority were to require us to conduct clinical trials beyond those which we currently anticipate will be required for the completion of clinical development of any of our products or product candidates or if we experience significant delays in enrollment in any of our clinical trials, we could be required to expend significant additional financial resources and time on the completion of clinical development.

Selling, general and administrative expense

Selling, general and administrative expenses consist primarily of salaries and other related costs for personnel, including share-based compensation expenses, in our executive, legal, business development, commercial, finance, accounting, information technology and human resource functions. Other selling, general and administrative expenses include facility-related costs not otherwise included in research and development expense; advertising and promotional expenses; costs associated with industry and trade shows; and professional fees for legal services, including patent-related expenses, accounting services and miscellaneous selling costs.

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We expect that we will continue to incur significant selling, general and administrative expenses in future periods in connection with our continued efforts to commercialize our products, including increased payroll, expanded infrastructure, commercial operations, increased consulting, legal, accounting and investor relations expenses.

Interest expense, net

Interest expense, net consists of interest expense from the liability for the sale of future royalties related to the Original Royalty Purchase Agreement, the A&R Royalty Purchase Agreement, the 2026 Convertible Notes outstanding and the Blackstone Credit Agreement that we repaid and terminated in October 2023, offset by interest income earned on investments.

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 financial statements, which we have prepared in accordance with generally accepted accounting principles in the United States. The preparation of these 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 financial statements, as well as the reported revenues and expenses during the reporting periods. Actual results may differ from these estimates under different assumptions or conditions.

Of our policies, revenue recognition related to net product revenue is considered critical to an understanding of our consolidated financial statements as it requires the application of the most subjective and complex judgment, involving critical accounting estimates and assumptions impacting our consolidated financial statements.

Revenue recognition related to net product revenue

Net product revenues. Our net product revenue primarily consists of sales of Translarna in territories outside of the U.S. and sales of Emflaza in the U.S., both for the treatment of DMD. Beginning in the second half of 2025, our net product revenues also includes sales of Sephience for the treatment of PKU. We recognize revenue when performance obligations with customers have been satisfied. Our performance obligations are to provide products based on customer orders from distributors, hospitals, specialty pharmacies or retail pharmacies. The performance obligations are satisfied at a point in time when our customer obtains control of the product, which is typically upon delivery. We invoice customers after the products have been delivered and invoice payments are generally due within 30 to 90 days of invoice date. We determine the transaction price based on fixed consideration in its contractual agreements. Contract liabilities arise in certain circumstances when consideration is due for goods not yet provided. As we have identified only one distinct performance obligation, the transaction price is allocated entirely to the product sale. In determining the transaction price, a significant financing component does not exist since the timing from when we deliver product to when the customers pay for the product is typically less than one year. Customers in certain countries pay in advance of product delivery. In those instances, payment and delivery typically occur in the same month.

We record product sales net of any variable consideration, which includes discounts, allowances, rebates related to Medicaid and other government pricing programs, and distribution fees. We use the expected value or most likely amount method when estimating variable consideration, unless discount or rebate terms are specified within contracts. The identified variable consideration is recorded as a reduction of revenue at the time revenues from product sales are recognized. These estimates for variable consideration are adjusted to reflect known changes in factors and may impact such estimates in the quarter those changes are known. Revenue recognized does not include amounts of variable consideration that are constrained.

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During the years ended December 31, 2025, 2024, and 2023, net product revenues consisted of the following:

​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

​ ​ Years ended December 31,

​

Disaggregated net product revenues by country for the years ended December 31, 2025, 2024, and 2023 are as follows:

​ ​ ​ ​ ​ ​ ​ ​ ​ ​

​ ​ Years ended December 31,

​

Sales of Translarna in France are not depicted in the net product revenue tables above. See “Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations- Results of operations- Year ended December 31, 2025 compared to year ended December 31, 2024” for additional information.

For the year ended December 31, 2025, four of our distributors each accounted for over 10% of our net product sales. For the years ended December 31, 2024 and 2023, two of our distributors each accounted for over 10% of our net product sales.

In relation to customer contracts, we incur costs to fulfill a contract but do not incur costs to obtain a contract. These costs to fulfill a contract do not meet the criteria for capitalization and are expensed as incurred. We consider any shipping and handling costs that are incurred after the customer has obtained control of the product as a cost to fulfill a promise. Shipping and handling costs associated with finished goods delivered to customers are recorded as a selling expense.

For a description of our significant accounting policies, see Note 2 to our consolidated financial statements.

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Results of operations

Year ended December 31, 2025 compared to year ended December 31, 2024

The following table summarizes revenues and selected expense and other income data for the year ended December 31, 2025 and 2024:

​

​ ​ ​ ​ ​ ​ ​ ​ ​ ​

​ ​ Year ended ​ ​ ​

​ ​ December 31, ​ Change

Manufacturing revenue ​ ​ — ​ ​ 1,661 ​ $ (1,661)

Change in the fair value of contingent consideration ​ (800) ​ (4,475) ​ $ 3,675

Gain on sale of priority review voucher ​ ​ — ​ ​ 99,900 ​ $ (99,900)

​

Net product revenue. Net product revenue was $586.7 million for the year ended December 31, 2025, an increase of $4.6 million, or 1%, from net product revenue of $582.1 million for the year ended December 31, 2024. The increase in net product revenue was primarily due to an increase in net product sales of Sephience and Upstaza/Kebilidi, with Sephience and Kebilidi sales beginning in the second half of 2025. This increase was partially offset by a decrease in net product sales of Emflaza and Translarna. The decrease in Emflaza sales is primarily driven by additional generic competition. The decrease in Translarna sales is primarily due to the EC’s adoption of the CHMP’s negative opinion.

Collaboration and license revenue. Collaboration and license revenue was $998.4 million for the year ended December 31, 2025, an increase of $998.1 million, or over 100%, from collaboration revenue of $0.3 million for the year ended December 31, 2024. The increase in collaboration and license revenue was primarily due to the recognition of $1.0 billion of license revenues from the Novartis Agreement related to our votoplam HD program, which was partially offset by a $3.5 million refund for a prior collaboration arrangement in relation to votoplam.

Royalty revenue. Royalty revenue was $244.2 million for the year ended December 31, 2025, an increase of $40.4 million, or 20%, from $203.9 million for the year ended December 31, 2024. The increase in royalty revenue was due to higher Evrysdi sales in the year ended December 31, 2025, compared to the year ended December 31, 2024. In accordance with the SMA License Agreement, we record royalty revenues based on worldwide annual net sales of the product.

Translarna France.In the year ended December 31, 2025, we changed our estimates for our sales allowance related to Translarna revenues in France, primarily based on our recent communications with the French pricing authorities subsequent to the EC’s adoption of the opinion of the CHMP of the EMA to not renew the authorization of Translarna for the treatment of nmDMD. This change in estimate for sales allowance resulted in an increase of $98.6 million to the sales allowance reserve, which resulted in a decrease to net product revenues of $98.6 million. The $98.6 million change in sales allowance estimate represents a life to date adjustment for the historical sales of Translarna in France. Translarna France revenues were reclassified from net product revenues to the Translarna France line item on the consolidated statement of

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operations for the periods ended December 31, 2024 and December 31, 2023 to allow revenue for sales of Translarna in France to be comparable.

Manufacturing revenue. Manufacturing revenue was $0.0 million for the year ended December 31, 2025, a decrease of $1.7 million, or 100%, from $1.7 million for the year ended December 31, 2024. The decrease was due to the prior completion of all manufacturing services related to the production of plasmid DNA and AAV vectors for gene therapy applications for external customers. In June 2024, we sold our gene therapy manufacturing business in Hopewell Township, New Jersey. Accordingly, we do not expect to have manufacturing revenue going forward.

Cost of product, collaboration and license sales, excluding amortization of acquired intangible assets. Cost of product sales, collaboration and license sales, excluding amortization of acquired intangible assets, was $47.0 million for the year ended December 31, 2025, a decrease of $10.4 million, or 18%, from $57.4 million for the year ended December 31, 2024. Cost of product sales, collaboration and license sales, excluding amortization of acquired intangible assets consisted primarily of costs associated with the Novartis Agreement, as well as production costs, royalty payments, inventory reserves, and costs associated with sales of Emflaza, Translarna, Sephience, and Upstaza/Kebilidi. The decrease was primarily due to decreases in royalty costs driven by Emflaza as a result of the completion of the royalty agreement with Marathon Pharmaceuticals, LLC (now known as Complete Pharma Holdings, LLC), which was partially offset by costs associated with the Novartis Agreement, inventory costs associated with the Sephience launch, Upstaza/Kebilidi and Sephience royalty payments, an increase in inventory reserves, and costs associated with new product sales.

Amortization of acquired intangible asset. Amortization of acquired intangible asset was $24.7 million for the year ended December 31, 2025, a decrease of $36.0 million, or 59%, from $60.7 million for the year ended December 31, 2024. These amounts are related to the Waylivra, Tegsedi, Upstaza/Kebilidi, Sephience, and Emflaza intangible assets, which are all being amortized on a straight-line basis over their estimated useful lives. The amortization decrease was primarily driven by the Emflaza intangible asset being fully amortized as of February 2024. As a result, there is no further amortization for Emflaza as of February 2024. This decrease was partially offset by increases to the intangible assets balance for Upstaza/Kebilidi and Sephience assets recorded as a result of regulatory approvals as well as the Censa Rights Satisfaction Agreement, which increased the corresponding amortization for those assets.

Research and development. Research and development was $455.2 million for the year ended December 31, 2025, a decrease of $79.2 million, or 15%, compared to $534.5 million for the year ended December 31, 2024. The decrease in research and development expenses related to decreases in program spend as we continued to focus our resources on our differentiated, high potential research and development programs. For the year ended December 31, 2024, research and development expense also included a total of $65.0 million of regulatory success-based milestones paid to the former Censa securityholders.

Selling, general and administrative. Selling, general and administrative was $347.1 million for the year ended December 31, 2025, an increase of $46.2 million, or 15%, from $300.9 million for the year ended December 31, 2024. The increase reflected our continued investment to support our commercial activities including our expanding commercial portfolio.

Change in the fair value of contingent consideration. Change in the fair value of contingent consideration was a gain of $0.8 million for the year ended December 31, 2025, a decrease of $3.7 million, or 82%, from a gain of $4.5 million for the year ended December 31, 2024. During the year ended December 31, 2025, the probability of triggering the remaining contingent consideration was determined to be remote, and therefore the balance was written down to zero.

Intangible asset impairment. Intangible asset impairment was $0.0 million for the year ended December 31, 2025, a decrease of $159.5 million, or 100%, from $159.5 million for the year ended December 31, 2024. During the year ended December 31, 2024, as a result of our annual impairment test for our PTC-AADC indefinite lived intangible asset, we impaired $159.5 million due to a decrease in projected cash flows due to refinements in current market assumptions and the timing of patient treatments.

Tangible asset impairment and (gains) losses on transactions, net. Tangible asset impairment and (gains) losses on transactions, net was a gain of $9.6 million for the year ended December 31, 2025, an increase of $10.4 million, or over

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100%, from a loss of $0.8 million for the year ended December 31, 2024. The increase in tangible asset impairment and (gains) losses on transactions, net, was primarily due to a $10.8 million gain on the MassBio lease modification, partially offset by a loss of $1.0 million in fixed asset impairments in connection with office relocations and closures, as well as a $0.1 million loss related to the sale of fixed assets for the year ended December 31, 2025. The loss for the year ended December 31, 2024 was due to a $4.4 million loss primarily related to the sale of certain assets for gene therapy manufacturing, and a $4.1 million loss primarily related to fixed asset impairments in connection with the South Plainfield, New Jersey office closure and Warren, New Jersey lease modification. These amounts were partially offset by a gain of $2.2 million on lease terminations, and a gain of $5.5 million on lease modifications.

Interest expense, net. Interest expense, net was $152.2 million for the year ended December 31, 2025, a decrease of $14.8 million, or 9%, from interest expense, net of $167.0 million for the year ended December 31, 2024. The decrease in interest expense, net was primarily due to an increase in interest income from marketable securities-available for sale, offset by an increase in interest expense related to the liability for the sale of future royalties related to the A&R Royalty Purchase Agreement.

Other (expense) income, net. Other expense, net was $18.1 million for the year ended December 31, 2025, a change of $24.6 million, or over 100%, from other income, net of $6.5 million for the year ended December 31, 2024. The change in other (expense) income, net primarily relates to unrealized and realized foreign exchange losses of $23.1 million for the year ended December 31, 2025, as compared to unrealized and realized foreign exchange gains of $1.1 million the year ended December 31, 2024.

Gain on sale of priority review voucher. Gain on sale of priority review voucher was $0.0 million for the year ended December 31, 2025, a decrease of $99.9 million, or 100%, from gain on sale of priority review voucher of $99.9 million for the year ended December 31, 2024. For the year ended December 31, 2024, in connection with our FDA approval of Kebilidi, we received a Priority Review Voucher, or PRV, and sold the PRV for aggregate net proceeds of $148.0 million. We had previously recorded an indefinite lived intangible asset for the PRV of $48.1 million in connection with the acquisition of Agilis in 2018, which was included as part of the book balance of our PTC-AADC indefinite lived intangible asset balance. Accordingly, we derecognized the book value of the PRV and recorded a gain of $99.9 million upon the sale.

Income tax expense. Income tax expense was $14.0 million for the year ended December 31, 2025, an increase of $13.8 million, or over 100%, from income tax expense of $0.2 million for the year ended December 31, 2024. The increase in income tax expense was driven by the income recognized related to the Novartis Agreement. Additionally, we incur income tax expenses in various foreign jurisdictions, and our foreign tax liabilities are largely dependent upon the distribution of pre-tax earnings among these different jurisdictions.

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Year ended December 31, 2024 compared to year ended December 31, 2023

The following table summarizes revenues and selected expense and other income data for the years ended December 31, 2024 and 2023:

​

​ ​ ​ ​ ​ ​ ​ ​ ​ ​

​ ​ Year ended ​ ​ ​

​ ​ December 31, ​ Change

Tangible asset impairment and losses on transactions, net ​ ​ 750 ​ ​ — ​ $ 750

Gain on sale of priority review voucher ​ ​ 99,900 ​ ​ — ​ $ 99,900

Loss on extinguishment of debt ​ ​ — ​ ​ (137,558) ​ $ 137,558

​

Net product revenue. Net product revenue was $582.1 million for the year ended December 31, 2024, a decrease of $56.0 million, or 9%, from net product revenue of $638.2 million for the year ended December 31, 2023. Translarna net product revenues were $321.1 million for the year ended December 31, 2024, a decrease of $11.7 million, or 4%, compared to $332.8 million for the year ended December 31, 2023. These results were due to the timing of bulk patient orders, as well as the residual impact from the CHMP negative opinion in September 2023. Emflaza net product revenues were $207.2 million for the year ended December 31, 2024, a decrease of $47.9 million, or 19%, compared to $255.1 million for the year ended December 31, 2023. These results were driven by the expiration of Emflaza’s orphan drug exclusivity in February 2024. The remaining change of $3.5 million was due to an increase of $5.4 million in net product sales relating to Tegsedi and Waylivra, and a decrease in net product sales of $1.9 million relating to Upstaza.

Collaboration revenue. Collaboration revenue was $0.3 million for the year ended December 31, 2024, a decrease of $99.7 million, or 100%, from collaboration revenue of $100.0 million for the year ended December 31, 2023. The decrease relates to a sales milestone of $100.0 million that was recognized for the achievement of $1.5 billion in worldwide annual net sales from Evrysdi in the year ended December 31, 2023.

Royalty revenue. Royalty revenue was $203.9 million for the year ended December 31, 2024, an increase of $35.0 million, or 21%, from $168.9 million for the year ended December 31, 2023. The increase in royalty revenue was due to higher Evrysdi sales in the year ended December 31, 2024, compared to the year ended December 31, 2023. In accordance with the SMA License Agreement, we record royalty revenues based on worldwide annual net sales of Evrysdi.

Translarna France.In the year ended December 31, 2025, we changed our estimates for our sales allowance related to Translarna revenues in France, primarily based on our recent communications with the French pricing authorities subsequent to the EC’s adoption of the opinion of the CHMP of the EMA to not renew the authorization of Translarna for the treatment of nmDMD. Translarna France revenues were reclassified from net product revenues to the Translarna France line item on the consolidated statement of operations for the periods ended December 31, 2024 and December 31, 2023 to allow revenue for sales of Translarna in France to be comparable.

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Manufacturing revenue. Manufacturing revenues were $1.7 million for the year ended December 31, 2024, a decrease of $6.0 million, or 78%, from $7.7 million for the year ended December 31, 2023. The decrease was due to the completion of all manufacturing services related to the production of plasmid DNA and AAV vectors for gene therapy applications for external customers. In June 2024, we sold our gene therapy manufacturing business in Hopewell Township, New Jersey. Accordingly, we do not expect to have manufacturing revenue going forward.

Cost of product sales, excluding amortization of acquired intangible asset. Cost of product sales, excluding amortization of acquired intangible asset, was $57.4 million for the year ended December 31, 2024, a decrease of $8.1 million, or 12%, from $65.5 million for the year ended December 31, 2023. Cost of product sales excluding amortization of acquired intangible asset consisted primarily of royalty payments associated with Emflaza, Translarna, and Upstaza net product sales, costs associated with Emflaza, Translarna, and Upstaza products sold during the period, and royalty expense related to royalty revenues and collaboration milestone revenues. The decrease in cost of product sales, excluding amortization of acquired intangible asset, was primarily due to decreases in costs related to royalty and collaboration revenues, partially offset by increases in royalty costs driven by Emflaza.

Amortization of acquired intangible asset. Amortization of acquired intangible asset was $60.7 million for the year ended December 31, 2024, a decrease of $161.9 million, or 73%, from $222.6 million for the year ended December 31, 2023. These amounts are related to the Emflaza rights acquisition, as well as the Waylivra, Tegsedi, and Upstaza/Kebilidi intangible assets, which are all being amortized on a straight-line basis over their estimated useful lives. The amortization decrease was driven by the Emflaza rights intangible asset being fully amortized as of February 2024, therefore, milestones are recorded on the consolidated statement of operations within cost of product sales, excluding amortization of acquired intangible assets from February 2024 onward.

Research and development expense. Research and development expense was $534.5 million for the year ended December 31, 2024, a decrease of $132.1 million, or 20%, compared to $666.6 million for the year ended December 31, 2023. The decrease in research and development expenses related to decreases in program spend related to our strategic portfolio prioritization as we continued to focus our resources on our differentiated, high potential research and development programs. Research and development expense also included a total of $65.0 million of regulatory success-based milestones paid to the former Censa securityholders for the year ended December 31, 2024, as compared to a $30.0 million success-based development milestone paid to the former Censa securityholders for the year ended December 31, 2023.

Selling, general and administrative expense. Selling, general and administrative expense was $300.9 million for the year ended December 31, 2024, a decrease of $31.6 million, or 10%, from $332.5 million for the year ended December 31, 2023. The decrease reflected lower employee costs as a result of the reduction in workforce in 2023.

Change in the fair value of contingent consideration. Change in the fair value of contingent consideration was a gain of $4.5 million for the year ended December 31, 2024, a decrease of $123.2 million, or 96%, from a gain of $127.7 million for the year ended December 31, 2023. The decrease is primarily related to our strategic portfolio prioritization in 2023 and decision to discontinue our preclinical and early research programs in our gene therapy platform in May 2023, which included programs for FA and Angelman syndrome. As a result, we fully impaired the FA and Angelman syndrome intangible assets and determined that the fair value for all of the contingent consideration payable related to FA and Angelman syndrome was $0. As a result, we recorded a fair value change of $128.4 million for the year ended December 31, 2023 for the contingent consideration related to FA and Angelman syndrome.

Intangible asset impairment. Intangible asset impairment was $159.5 million for the year ended December 31, 2024, a decrease of $58.3 million, or 27%, from intangible asset impairment of $217.8 million for the year ended December 31, 2023. During the year ended December 31, 2024, as a result of our annual impairment test for our PTC-AADC indefinite lived intangible asset, we impaired $159.5 million due to a decrease in projected cash flows due to refinements in current market assumptions and the timing of patient treatments. During the year ended December 31, 2023, as a result of our strategic portfolio prioritization in 2023 and decision to discontinue our preclinical and early research programs in our gene therapy platform, which included programs for FA and Angelman syndrome, we fully impaired the FA and Angelman syndrome intangible assets and recorded impairment expense of $217.8 million.

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Tangible asset impairment and losses (gains) on transactions, net. Tangible asset impairment and losses (gains) on transactions, net was $0.8 million for the year ended December 31, 2024, an increase of $0.8 million, or 100%, from impairment of tangible assets of $0.0 million for the year ended December 31, 2023. The increase in tangible asset impairment and losses (gains) on transactions, net, was due to a $4.4 million loss primarily related to the sale of certain assets for gene therapy manufacturing, and a $4.1 million loss primarily related to fixed asset impairments in connection with the South Plainfield, New Jersey office closure and Warren, New Jersey lease modification. These amounts were partially offset by a gain of $2.2 million on lease terminations, and a gain of $5.5 million on lease modifications.

Interest expense, net. Interest expense, net was $167.0 million for the year ended December 31, 2024, an increase of $37.8 million, or 29%, from interest expense, net of $129.2 million for the year ended December 31, 2023. The increase in interest expense, net was primarily due to interest expense recorded from the liability for the sale of future royalties related to the A&R Royalty Purchase Agreement and the Original Royalty Purchase Agreement, offset by a decrease in interest expense due to the termination of our Blackstone Credit Agreement.

Other income, net. Other income, net was $6.5 million for the year ended December 31, 2024, a decrease of $3.6 million, or 35%, from other income, net of $10.1 million for the year ended December 31, 2023. The decrease in other income, net resulted primarily from a decrease in unrealized and realized foreign exchange gains of $8.0 million for the year ended December 31, 2024 as compared to the year ended December 31, 2023. In addition, we had unrealized gains on our ClearPoint equity investments of $7.7 million and unrealized and realized losses on our ClearPoint convertible debt security of $2.6 million for the year ended December 31, 2024, as compared to unrealized and realized losses on our ClearPoint equity investments and ClearPoint convertible debt security of $2.3 million and $2.7 million, respectively, for the year ended December 31, 2023. For the years ended December 31, 2024 and 2023, we had net realized gains of $0.1 million on marketable securities – available for sale and $4.8 million on marketable securities – equity investments, respectively.

Gain on sale of priority review voucher. Gain on sale of priority review voucher was $99.9 million for the year ended December 31, 2024, an increase of $99.9 million, or 100%, from gain on sale of priority review voucher of $0.0 million for the year ended December 31, 2023. In connection with our FDA approval of Kebilidi, we received a PRV and sold the PRV for aggregate net proceeds of $148.0 million. We had previously recorded an indefinite lived intangible asset for the PRV of $48.1 million in connection with the acquisition of Agilis in 2018, which was included as part of the book balance of our PTC-AADC indefinite lived intangible asset balance. Accordingly, we derecognized the book value of the PRV and recorded a gain of $99.9 million upon the sale.

Loss on extinguishment of debt. Loss on extinguishment of debt was $0.0 million for the year ended December 31, 2024, a decrease of $137.6 million, or 100%, from loss on extinguishment of debt of $137.6 million for the year ended December 31, 2023. The decrease was primarily due to the early termination of our Blackstone Credit Agreement in 2023, with no similar event occurring in 2024. We recorded a loss on the extinguishment of debt of $92.7 million for the period ended December 31, 2023. The loss on extinguishment of debt consisted of $82.0 million in prepayment premiums, exit fees, and creditor expenses and debt issuance costs of $10.7 million. In addition, we recorded $44.9 million on the loss of extinguishment of debt relating to the A&R Royalty Purchase Agreement.

Income tax (expense) benefit. Income tax expense was $0.2 million for the year ended December 31, 2024, a change of $69.7 million, or over 100%, from income tax benefit of $69.5 million for the year ended December 31, 2023. The change in income tax (expense) benefit was attributable to an increase of current federal and state tax expense driven by the recognition of previously deferred revenue from the A&R Royalty Purchase Agreement.

Liquidity and capital resources

Sources of liquidity

While we have generated net income in the year ended December 31, 2025, we have historically incurred significant operating losses.

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As a growing commercial-stage biopharmaceutical company, we are engaging in significant commercialization efforts for our products while also devoting a substantial portion of our efforts on research and development related to our products, product candidates and other programs. To date, our product revenue has primarily consisted of sales of Translarna for the treatment of nmDMD in territories outside of the United States and from Emflaza for the treatment of DMD in the United States. Beginning in the second half of 2025, our net product revenues also includes sales of Sephience for the treatment of PKU. Our ability to generate product revenue from any of our products will largely depend on the coverage and reimbursement levels set by governmental authorities, private health insurers and other third-party payors, as the case may be, depending on the country in which our products are marketed, and the rate and degree of market acceptance and clinical utility of any of our products.

Additionally, for Emflaza, its seven-year period of orphan drug exclusivity related to the treatment of DMD in patients five years and older expired in February 2024. With the expiration of this orphan drug exclusivity, we have seen an increase in competition from generics, which has, and we expect will continue to have, a negative impact on Emflaza net product revenue. Emflaza’s orphan drug exclusivity related to the treatment of DMD in patients two years of age to less than five expires in June 2026.

Additionally, for Translarna, our ongoing ability to generate revenue from sales of Translarna for the treatment of nmDMD is dependent upon our ability to maintain our marketing authorizations in other geographies and secure market access through commercial programs following the conclusion of pricing and reimbursement terms at sustainable levels in the member states of the EEA or through EAP programs or similar styled programs in the EEA and other territories. While Translarna previously had conditional approval in the EEA, in March 2025, the European Commission adopted the negative opinion of the Committee of Medicinal Products for Human Use, or CHMP, of the European Medicines Agency, or EMA, to not renew the conditional marketing authorization of Translarna for the treatment of nmDMD. However, the EC indicated that individual countries within the EU can leverage Articles 117(3) and 5(1) of the EU Directive 2001/83 to allow continued commercial use of Translarna. There is a substantial risk that as a result of the EC’s adoption of the CHMP’s negative opinion we will lose a significant portion of our ability to generate revenue from sales of Translarna in the EEA. Additionally, the loss of the Translarna marketing authorization in the EEA and the withdrawal of the Translarna NDA in the United States may influence regulatory entities in other jurisdictions in which Translarna has been approved to reassess such approvals. There is substantial risk that we will be unable to maintain our marketing authorizations in these countries. Even in countries where our marketing authorization is maintained, there may be an impact on pricing and reimbursement of Translarna within those countries.

We have financed our operations to date primarily through private offerings of convertible senior notes, public and “at the market offerings” of common stock, proceeds from royalty purchase agreements, private placements of our convertible preferred stock and common stock, collaborations, bank and institutional lender debt, other convertible debt, grant funding and clinical trial support from governmental and philanthropic organizations and patient advocacy groups in the disease areas addressed by our product candidates. We expect to continue to incur significant expenses and operating losses for at least the next fiscal year. The net losses we incur may fluctuate significantly from quarter to quarter.

In August 2019, we entered into the Sales Agreement, pursuant to which, we may offer and sell shares of our common stock, having an aggregate offering price of up to $125.0 million from time to time through the Sales Agents by any method that is deemed to be an “at the market offering” as defined in Rule 415(a)(4) promulgated under the Securities Act. See “Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations—Overview—Funding” for additional information.

In September 2019, we issued $287.5 million aggregate principal amount of 2026 Convertible Notes, which included an option to purchase up to an additional $37.5 million in aggregate principal amount of the 2026 Convertible Notes, which was exercised in full by the initial purchasers. The 2026 Convertible Notes bear cash interest at a rate of 1.50% per year, payable semi-annually on March 15 and September 15 of each year, beginning on March 15, 2020. The 2026 Convertible Notes will mature on September 15, 2026, unless earlier repurchased or converted. We received net proceeds of $279.3 million after deducting the initial purchasers’ discounts and commissions and the offering expenses payable by us.

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Holders may convert their 2026 Convertible Notes at their option at any time prior to the close of business on the business day immediately preceding March 15, 2026 only under the following circumstances: (1) during any calendar quarter commencing on or after December 31, 2019 (and only during such calendar quarter), if the last reported sale price of our common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price on each applicable trading day; (2) during the five business day period after any five consecutive trading day period, or the measurement period, in which the trading price (as defined in the 2026 Convertible Notes Indenture) per $1,000 principal amount of 2026 Convertible Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price of our common stock and the conversion rate on each such trading day; (3) during any period after we have issued notice of redemption until the close of business on the scheduled trading day immediately preceding the relevant redemption date; or (4) upon the occurrence of specified corporate events. The 2026 Convertible Notes are currently convertible. On or after March 15, 2026, until the close of business on the business day immediately preceding the maturity date, holders may convert their 2026 Convertible Notes at any time, regardless of the foregoing circumstances. Upon conversion, we will pay or deliver, as the case may be, cash, shares of our common stock or any combination thereof at our election. The 2026 Convertible Notes will mature on September 15, 2026, unless earlier redeemed or converted.

The conversion rate for the 2026 Convertible Notes was initially, and remains, 19.0404 shares of our common stock per $1,000 principal amount of the 2026 Convertible Notes, which is equivalent to an initial conversion price of approximately $52.52 per share of our common stock. The conversion rate may be subject to adjustment in some events but will not be adjusted for any accrued and unpaid interest.

We were not permitted to redeem the 2026 Convertible Notes prior to September 20, 2023. We may redeem for cash all or any portion of the 2026 Convertible Notes, at our option, if the last reported sale price of our common stock has been at least 130% of the conversion price then in effect on the last trading day of, and for at least 19 other trading days (whether or not consecutive) during, any 30 consecutive trading day period ending on, and including, the trading day immediately preceding the date on which we provide notice of redemption, at a redemption price equal to 100% of the principal amount of the 2026 Convertible Notes to be redeemed, plus accrued and unpaid interest to, but excluding, the redemption date. No sinking fund is provided for the 2026 Convertible Notes, which means that we are not required to redeem or retire the 2026 Convertible Notes periodically.

If we undergo a “fundamental change” (as defined in the 2026 Convertible Notes Indenture), subject to certain conditions, holders of the 2026 Convertible Notes may require us to repurchase for cash all or part of their 2026 Convertible Notes at a repurchase price equal to 100% of the principal amount of the 2026 Convertible Notes to be repurchased, plus accrued and unpaid interest to, but excluding, the fundamental change repurchase date.

The 2026 Convertible Notes represent senior unsecured obligations and will rank senior in right of payment to our future indebtedness that is expressly subordinated in right of payment to the notes, equal in right of payment to our existing and future unsecured indebtedness that is not so subordinated, effectively junior in right of payment to any of our secured indebtedness to the extent of the value of the assets securing such indebtedness, and structurally subordinated to all existing and future indebtedness and other liabilities (including trade payables) incurred by our subsidiaries. The 2026 Convertible Notes Indenture contains customary events of default with respect to the 2026 Convertible Notes, including that upon certain events of default (including our failure to make any payment of principal or interest on the 2026 Convertible Notes when due and payable) occurring and continuing, the 2026 Convertible Notes Trustee by notice to us, or the holders of at least 25% in principal amount of the outstanding 2026 Convertible Notes by notice to us and the Convertible Notes Trustee, may, and the 2026 Convertible Notes Trustee at the request of such holders (subject to the provisions of the 2026 Convertible Notes Indenture) will, declare 100% of the principal of and accrued and unpaid interest, if any, on all the 2026 Convertible Notes to be due and payable. In case of certain events of bankruptcy, insolvency or reorganization, involving us or a significant subsidiary, 100% of the principal of and accrued and unpaid interest on the 2026 Convertible Notes will automatically become due and payable. Upon such a declaration of acceleration, such principal and accrued and unpaid interest, if any, will be due and payable immediately.

In October 2023, we terminated the Blackstone Credit Agreement. We recorded a loss on the extinguishment of debt of $92.7 million which is included on the statement of operations for the period ended December 31, 2023. The loss on

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extinguishment of debt consisted of $82.0 million in prepayment premiums, exit fees, and creditor expenses and debt issuance costs of $10.7 million. All liens and security interests securing the loans made pursuant to the Blackstone Credit Agreement were released upon termination.

We have received fundings from Royalty Pharma under the A&R Royalty Purchase Agreement in July 2020, October 2023, June 2024 and December 2025, totaling $2.1 billion. In exchange for these fundings, we sold Royalty Pharma 100% of the Royalty.

In November 2024, we and Novartis entered into the Novartis Agreement relating to our votoplam HD program which includes related molecules. Pursuant to the Novartis Agreement, we were responsible for conducting the Phase 2A clinical trial of votoplam, which is complete, and have transitioned sponsorship of the ongoing OLE clinical trial to Novartis. Novartis will be responsible for all other development of licensed compounds and licensed products and the manufacture and commercialization of licensed compounds and licensed products worldwide. Under the Novartis Agreement, and upon the closing of the transaction contemplated by the Novartis Agreement in January 2025, we received an upfront payment of $1.0 billion on the effective date and can receive up to $1.9 billion in development, regulatory and sales milestones, a 40% share of U.S. profits and losses, and tiered double-digit royalties on ex-U.S. sales.

Cash flows

As of December 31, 2025, we had cash and cash equivalents and marketable securities of $1,945.4 million.

The following table provides information regarding our cash flows and our capital expenditures for the periods indicated.

​

​ ​ ​ ​ ​ ​ ​ ​ ​ ​

​ ​ Years ended

​ ​ December 31,

Cash provided (used in) by: ​ ​ ​ ​ ​ ​ ​

​

Net cash provided by operating activities was $711.2 million for the year ended December 31, 2025. Net cash used in operating activities was $107.7 million, and $158.4 million for the years ended December 31, 2024, and 2023, respectively. The net cash provided by operating activities for the year ended December 31, 2025, was primarily related to the upfront payment of $1.0 billion in cash received upon the closing of the Novartis Agreement in January 2025, partially offset by spend supporting clinical development and commercial activities. The net cash used in operating activities primarily related to supporting clinical development and commercial activities for the years ended December 31, 2024, and 2023.

Net cash used in investing activities was $862.0 million for the year ended December 31, 2025. Net cash provided by investing activities was $44.2 million for the year ended December 31, 2024. Net cash used in investing activities was $176.7 million for the year ended December 31, 2023. The cash used in investing activities for the year ended December 31, 2025, was primarily attributable to acquisition of product rights, purchases of marketable securities, and purchases of fixed assets, offset by the sale of marketable securities, sale of ClearPoint equity investments, and proceeds from sales of fixed assets. The cash provided by investing activities for the year ended December 31, 2024 was primarily attributable to the sale of marketable securities, proceeds from sales of fixed assets, proceeds from the sale of the PRV, and proceeds from settlement of the ClearPoint convertible debt security, offset by the acquisition of product rights, purchases of marketable securities, and purchases of fixed assets. The cash used in investing activities for the year ended December 31, 2023 is primarily attributable to the purchases of marketable securities, purchases of fixed assets, and the acquisition of product rights, offset by the sale of marketable securities and the sale of ClearPoint equity investments.

Net cash provided by financing activities was $331.1 million, $255.9 million, and $646.4 million for the years ended December 31, 2025, 2024 and 2023, respectively. The cash provided by financing activities for the years ended December 31, 2025 and 2024 were primarily attributable to the proceeds received from the A&R Royalty Purchase

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Agreement, exercise of options, issuance of stock under our Employee Stock Purchase Plan, or ESPP, offset by payments on contingent consideration obligation, and payments on our finance lease principal. The cash provided by financing activities for the year ended December 31, 2023 was primarily attributable to the proceeds received from the A&R Royalty Purchase Agreement, exercise of options, issuance of stock under our ESPP, offset by the repayment of the senior secured term loan, debt issuance costs, debt extinguishment costs related to senior secured term loan, and payments on our finance lease principal.

Funding requirements

We anticipate that we will continue to incur significant expenses in connection with our commercialization efforts in the United States, the EEA, Latin America, Japan and other territories, including expenses related to our commercial infrastructure and corresponding sales and marketing, legal and regulatory, and distribution and manufacturing undertakings as well as administrative and employee-based expenses. In addition to the foregoing, we expect to continue to incur significant costs in connection with ongoing, planned and potential future clinical trials and studies for our splicing and inflammation and ferroptosis programs as well as studies in our products for maintaining authorizations, label extensions and additional indications.These efforts may significantly impact the timing and extent of our commercialization and manufacturing expenses.

In addition, our expenses will increase if and as we:

● seek to discover and develop additional product candidates;

● maintain, expand and protect our intellectual property portfolio; and

We believe that our cash flows from product sales, together with existing cash and cash equivalents, and marketable securities, will be sufficient to fund our operating expenses and capital expenditure requirements for at least the next twelve months. We have based this estimate on assumptions that may prove to be wrong, and we could use our capital resources sooner than we currently expect.

Our future capital requirements will depend on many factors, including:

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● the timing and scope of any potential future growth in our employee base;

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With respect to our outstanding 2026 Convertible Notes, cash interest payments are payable on a semi-annual basis in arrears, which will require total funding of $4.3 million annually.

In June 2025, the EC granted marketing authorization to Sephience for the treatment of children and adults living with PKU in the EEA, which triggered a $25.0 million milestone payment to the former Censa securityholders. Pursuant to the Censa Merger Agreement, in July 2025, a $32.5 million milestone payment from the Company to the former Censa securityholders was triggered when the FDA approved Sephience for the treatment of children and adults living with PKU. Pursuant to the Censa Rights Satisfaction Agreement, in August 2025, an upfront cash consideration of $225.1 million was paid to the former Censa securityholders. The cash considerations and milestones were paid and recorded on the consolidated balance sheets within intangible asset, net during the year ended December 31, 2025.

On November 13, 2024, our BLA for Kebilidi for the treatment of AADC deficiency was approved by the FDA. In connection with the approval, we were granted a rare disease PRV. The FDA approval of the BLA and the PRV triggered $11.0 million regulatory milestone, which was paid during the year ended December 31, 2025. As of December 31, 2025, there are no remaining regulatory milestones. As of December 31, 2025, the remaining potential sales milestones related to Upstaza/Kebilidi is up to $50.0 million, however we have determined that the probability of triggering these milestones is remote.

We also have certain significant contractual obligations and commercial commitments that require funding. We lease office and shell condition, modifiable space for our principal office in Warren, New Jersey and we occupy under leases that expire in 2039, with three consecutive five-year renewal options to renew the leases at our option. Additionally, we entered into a lease agreement for approximately 103,000 square feet of laboratory and office space in Bridgewater, New Jersey. The rental term for such facility commenced on May 1, 2020 with an initial term of seven years and two consecutive five year renewal periods at our option. In addition, we lease office space, vehicles and equipment in various other locations in the U.S. and other countries for our employees and operations. We have a total of $156.9 million in obligations that stem from our operating leases.

We have a total of $6.0 million in obligations that stem from a commercial manufacturing services agreement entered into with MassBio on June 19, 2020. Pursuant to the terms of the agreement, MassBio agreed to provide us with four dedicated rooms for our Upstaza/Kebilidi program.

Under an Exclusive License and Supply Agreement, or the Faes Agreement, with Faes Farma, S.A., or Faes, we are required to pay royalties as a percentage of or as a fixed payment with respect to net product sales by us allocable to the Emflaza oral suspension product. We are required to pay Faes an annual royalty during the first twelve calendar years from the FDA approval date of the Emflaza oral suspension product.

Under various agreements, including the sponsored research agreement with the SMA Foundation discussed below, we will be required to pay royalties and milestone payments upon the successful development and commercialization of products.

We have entered into a sponsored research agreement with the SMA Foundation in connection with our SMA program. We may become obligated to pay the SMA Foundation single-digit royalties on worldwide net product sales of any collaboration product that we successfully develop and subsequently commercialize or, with respect to collaboration products we outlicense, including Evrysdi, a specified percentage of certain payments we receive from our licensee. We are not obligated to make such payments unless and until annual sales of a collaboration product exceed a designated threshold. Since inception, the SMA Foundation has earned $52.5 million, all of which was paid as of December 31, 2025. We have reached our obligation to make such payments to the SMA Foundation of an aggregate of $52.5 million as of December 31, 2025. Refer to “Ongoing Acquisition- Related Obligations” in Item 1. Business.

On May 29, 2020, we acquired Censa pursuant to an Agreement and Plan of Merger, dated as of May 5, 2020, or the Censa Merger Agreement, by and among us, Hydro Merger Sub, Inc., our wholly owned, indirect subsidiary, and, solely in its capacity as the representative, agent and attorney-in-fact of the securityholders of Censa, Shareholder Representative Services LLC, or the Censa Merger.

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In addition to the upfront consideration paid to the Censa securityholders upon the closing of the Censa Merger, pursuant to the Censa Merger Agreement, Censa securityholders will be entitled to receive contingent payments from us based on (i) the achievement of certain development and regulatory milestones up to an aggregate maximum amount of $217.5 million for sepiapterin’s two most advanced programs and receipt of a priority review voucher from the FDA as set forth in the Censa Merger Agreement, (ii) $109 million in development and regulatory milestones for each additional indication of sepiapterin, (iii) the achievement of certain net sales milestones up to an aggregate maximum amount of $160.0 million, including payments of $30.0 million for the first occurrence of a four consecutive calendar quarter period in which aggregate Net Sales of Product (as defined below) exceed $250.0 million, $50.0 million for the first occurrence of a four consecutive calendar quarter period in which aggregate Net Sales of Product exceed $500.0 million, and $80.0 million for the first occurrence of a four consecutive calendar quarter period in which aggregate Net Sales of Product exceed $1.0 billion (iv) a percentage of annual net sales during specified terms, equal to (a) 8% of annual Net Sales of Product for that portion of annual Net Sales of Product less than or equal to $250.0 million, (b) 10% of annual Net Sales of Product for that portion of annual Net Sales of Product greater than $250.0 million but less than $500.0 million and (c) 12% of annual Net Sales of Product for that portion of annual Net Sales of Product greater than $500.0 million, which we collectively refer to as the Net Sales Payments, and (v) any sublicense fees paid to us in consideration of any sublicense of Censa’s intellectual property to commercialize sepiapterin, on a country-by-country basis, which contingent payment will equal to a mid-double digit percentage of any such sublicense fees. We have paid $152.5 million in regulatory and development milestones related to Sephience, including in 2025, when we paid $25.0 million and $32.5 million in milestones to the former Censa securityholders when the EC granted marketing authorization to Sephience, and when the FDA approved Sephience for the treatment of children and adults living with PKU, respectively.

On August 5, 2025, we, certain of the former securityholders of Censa, or the Participating Rightsholders, and, for the limited purposes set forth in the agreement, Shareholder Representative Services LLC entered into a Rights Satisfaction Agreement, or the Rights Satisfaction Agreement, pursuant to which the Participating Rightsholders agreed to the cancellation and forfeiture of their rights to receive certain contingent payments from us based on worldwide annual net sales by us of products containing sepiapterin, or Net Sales of Product, under the Censa Merger Agreement in exchange for the consideration set forth in the Rights Satisfaction Agreement and further detailed below.

Pursuant to the terms of the Rights Satisfaction Agreement, the Participating Rightsholders have canceled and forfeited their rights under the Censa Merger Agreement to receive the Net Sales Payments.

​

In consideration of the foregoing, we agreed to pay to the Participating Rightsholders an aggregate amount in cash up to $250.0 million, or the Upfront Consideration, upon the consummation of the transactions contemplated by the Rights Satisfaction Agreement, or the Closing, and potential milestone payments, each, an Additional Milestone Payment, of up to $100.0 million each (or up to $500.0 million in the aggregate) based on the achievement of specified Net Sales Thresholds (as defined in the Censa Merger Agreement). The amount of the Upfront Consideration and the Additional Milestone Payments was subject to adjustment in the Rights Satisfaction Agreement based on the number of Participating Rightsholders.

At the Closing, based on the participation of former Censa securityholders holding approximately 90% of Censa’s equity securities prior to the consummation of the transactions contemplated by the Censa Merger Agreement, we paid an aggregate amount of Upfront Consideration in cash of $225.1 million. Additionally, we are obligated to make Additional Milestone Payments in an amount equal to approximately $90.0 million upon achievement of each of the (i) first occurrence of a three or fewer consecutive calendar year period in which aggregate Net Sales of Product are greater than $3.0 billion, (ii) first occurrence of a five or fewer consecutive calendar year period in which aggregate Net Sales of Product are greater than $5.0 billion, (iii) first occurrence of a seven or fewer consecutive calendar year period in which aggregate Net Sales of Product are greater than $7.0 billion, (iv) first occurrence of a nine or fewer consecutive calendar year period in which aggregate Net Sales of Product are greater than $9.0 billion and (v) first occurrence of an 11 or fewer consecutive calendar year period in which aggregate Net Sales of Product are greater than $11.0 billion. If any additional former securityholder of Censa executes and delivers a joinder to the Rights Satisfaction Agreement and becomes a party thereto, we will pay such former securityholder an amount in cash equal to such former securityholder’s applicable pro rata share of the Upfront Consideration (less any Net Sale Payments previously received) and any Additional Milestone Payments that become payable to Participating Rightsholders under the Rights Satisfaction Agreement.

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Additionally, we have employment agreements with certain employees which require the funding of a specific level of payments, if certain events, such as a change in control or termination without cause, occur.

We will need to generate significant revenues to achieve and sustain profitability and we may never do so. We may need to obtain substantial additional funding in connection with our continuing operations. Until such time, if ever, as we can generate substantial product revenues, we expect to finance our cash needs primarily through a combination of equity offerings, debt financings, collaborations, strategic alliances, grants and clinical trial support from governmental and philanthropic organizations and patient advocacy groups in the disease areas addressed by our product and product candidates and marketing, distribution or licensing arrangements. Adequate additional financing may not be available to us on acceptable terms, or at all. To the extent that we raise additional capital through the sale of equity or convertible debt securities, our stockholders ownership interest will be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect the rights of our common stockholders. Debt financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making capital expenditures or declaring dividends. If we raise additional funds through collaborations, strategic alliances or marketing, distribution or licensing arrangements with third parties, we may have to relinquish valuable rights to our technologies, future revenue streams, research programs or product candidates or to grant licenses on terms that may not be favorable to us.

If we are unable to raise additional funds through equity, debt or other financings when needed or on attractive terms, we may be required to delay, limit, reduce or terminate our product development or commercialization efforts or grant rights to develop and market product candidates that we would otherwise prefer to develop and market ourselves.

Item 7A. Quantitative and Qualitative Disclosures About Market Risk

We are exposed to market risk related to changes in interest rates. Our primary exposure to market risk is interest rate sensitivity, which is affected by changes in the general level of U.S. interest rates, particularly because our investments are in short-term securities. Our available for sale securities are subject to interest rate risk and will fall in value if market interest rates increase. At any time, sharp changes in interest rates can affect the fair value of the investment portfolio and its interest earnings. There were no investments classified as long-term at December 31, 2025. At December 31, 2025, we held $1,945.4 million in cash and cash equivalents and marketable securities. After a review of our marketable investment securities, we believe that in the event of a hypothetical ten percent increase in interest rates, the resulting decrease in fair value of our marketable investment securities would be insignificant to the consolidated financial statements.

Currently, we do not hedge these interest rate exposures. We maintain an investment portfolio in accordance with our investment policy. The primary objectives of our investment policy are to preserve principal, maintain proper liquidity and to meet operating needs. Although our investments are subject to credit risk, our investment policy specifies credit quality standards for our investments and limits the amount of credit exposure from any single issue, issuer or type of investment. Our investments are also subject to interest rate risk and will decrease in value if market interest rates increase. However, due to the conservative nature of our investments and relatively short duration, interest rate risk is mitigated. We do not own derivative financial instruments. Accordingly, we do not believe that there is any material market risk exposure with respect to derivative or other financial instruments.

As a result of our ex-U.S. operations, we face exposure to movements in foreign currency exchange rates, including the British Pound, Euro, Brazilian Real, and Swiss Franc against the U.S. dollar. The current exposures arise primarily from cash, accounts receivable, intercompany receivables and payables, intercompany loans and product sales denominated in foreign currencies. Both positive and negative impacts to our international product sales from movements in foreign currency exchange rates may be partially mitigated by the natural, opposite impact that foreign currency exchange rates have on our international operating expenses. For the year ended December 31, 2025, we recognized realized foreign currency transaction losses, net, of $11.3 million, which is recorded within other income, net on the Statement of Operations. A hypothetical ten percent increase or decrease in the exchange rate between the U.S. dollar and the British Pound, Euro, Brazilian Real, or Swiss Franc from the December 31, 2025 rate would not have a significant impact on our cash flows. We are not currently engaged in any foreign currency hedging activities. We will evaluate the use of derivative financial instruments to hedge our exposure as the needs and risks should arise.

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In September 2019, we issued $287.5 million of 1.50% convertible senior notes due September 15, 2026, or the 2026 Convertible Notes. We do not have economic interest rate exposure on the 2026 Convertible Notes as they have a fixed annual interest rate of 1.50%. However, the fair value of the 2026 Convertible Notes is exposed to interest rate risk. We do not carry the 2026 Convertible Notes at fair value on our balance sheet but present the fair value of the principal amount for disclosure purposes. Generally, the fair value of the 2026 Convertible Notes will increase as interest rates fall and decrease as interest rates rise. The 2026 Convertible Notes are also affected by the price and volatility of our common stock and will generally increase or decrease as the market price of our common stock changes. The estimated fair value of the 2026 Convertible Notes was approximately $424.5 million as of December 31, 2025.

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Item 8. Financial Statements and Supplementary Data

Index to consolidated financial statements

Report of Independent Registered Public Accounting Firm (PCAOB ID 42) 132

Notes to Consolidated Financial Statements 140

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Report of Independent Registered Public Accounting Firm

​

To the Stockholders and the Board of Directors of PTC Therapeutics, Inc.

​

Opinion on the Financial Statements

​

We have audited the accompanying consolidated balance sheets of PTC Therapeutics, Inc. (the Company) as of December 31, 2025 and 2024, the related consolidated statements of operations, comprehensive income (loss), stockholders' deficit and cash flows for each of the three years in the period ended December 31, 2025, and the related notes (collectively referred to as the “consolidated financial statements”). In our opinion, the consolidated financial statements present fairly, in all material respects, the financial position of the Company at December 31, 2025 and 2024, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2025, in conformity with U.S. generally accepted accounting principles.

​

We also have audited, in accordance with the standards of the Public Company Accounting Oversight Board (United States) (PCAOB), the Company's internal control over financial reporting as of December 31, 2025, based on criteria established in Internal Control—Integrated Framework issued by the Committee of Sponsoring Organizations of the Treadway Commission (2013 framework), and our report dated February 19, 2026 expressed an unqualified opinion thereon.

​

Basis for Opinion

​

These financial statements are the responsibility of the Company's management. Our responsibility is to express an opinion on the Company’s financial statements based on our audits. We are a public accounting firm registered with the 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 financial statements are free of material misstatement, whether due to error or fraud. Our audits included performing procedures to assess the risks of material misstatement of the 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 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 financial statements. We believe that our audits provide a reasonable basis for our opinion.

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Critical Audit Matter

​

The critical audit matter communicated below is a matter arising from the current period audit of the 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 financial statements and (2) involved our especially challenging, subjective or complex judgments. The communication of the 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.

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Variable consideration in contracts with customers relating to Medicaid

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/s/ Ernst & Young LLP

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We have served as the Company’s auditor since 2010.

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Iselin, New Jersey

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February 19, 2026

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PTC Therapeutics, Inc.

Consolidated Balance Sheets

In thousands, except shares

​

​ ​ ​ ​ ​ ​ ​ ​

​ ​ December 31, ​ December 31, ​

Assets ​ ​ ​ ​ ​ ​ ​

Current assets: ​ ​ ​ ​ ​

Prepaid expenses and other current assets ​ 67,309 ​ 44,087 ​

Liabilities and stockholders’ deficit ​ ​ ​ ​ ​

Current liabilities: ​ ​ ​ ​ ​

Accounts payable and accrued expenses ​ $ 381,272 ​ $ 304,292 ​

Current portion of long-term debt ​ 286,631 ​ — ​

Operating lease liabilities- current ​ ​ 12,484 ​ ​ 10,363 ​

Finance lease liabilities- current ​ ​ 3,000 ​ ​ 3,000 ​

Liability for sale of future royalties- current ​ ​ 283,000 ​ ​ 257,821 ​

Contingent consideration payable ​ — ​ 800 ​

Operating lease liabilities- noncurrent ​ ​ 93,583 ​ ​ 74,947 ​

Finance lease liabilities- noncurrent ​ ​ 3,000 ​ ​ 15,574 ​

Liability for sale of future royalties- noncurrent ​ ​ 2,025,366 ​ ​ 1,823,955 ​

Other long-term liabilities ​ ​ 13,704 ​ ​ 21,426 ​

Stockholders’ deficit: ​ ​ ​ ​ ​

Accumulated other comprehensive income (loss) ​ 10,501 ​ (25,886) ​

Total liabilities and stockholders’ deficit ​ $ 2,898,767 ​ $ 1,705,024 ​

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See accompanying consolidated notes.

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PTC Therapeutics, Inc.

Consolidated Statements of Operations

In thousands, except shares and per share data

​

​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

​ ​ ​ Year ended December 31,

Revenues: ​ ​ ​ ​ ​ ​ ​

Manufacturing revenue ​ ​ ​ — ​ ​ 1,661 ​ ​ 7,687

Operating expenses: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

Gain on sale of priority review voucher ​ ​ ​ — ​ ​ 99,900 ​ ​ —

Loss on extinguishment of debt ​ ​ ​ — ​ ​ — ​ ​ (137,558)

Weighted-average shares outstanding: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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See accompanying consolidated notes.

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PTC Therapeutics, Inc.

Consolidated Statements of Comprehensive Income (Loss)

In thousands

​

​ ​ ​ ​ ​ ​ ​ ​ ​ ​

​ ​ Year ended December 31,

Other comprehensive income (loss): ​ ​ ​ ​ ​ ​

Unrealized gain (loss) on marketable securities, net of tax ​ 518 ​ (57) ​ 820

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See accompanying consolidated notes.

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PTC Therapeutics, Inc.

Consolidated Statements of Stockholders’ Deficit

In thousands, except shares

​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

​ ​ ​ ​ ​ ​ ​ ​ Accumulated ​ ​ ​ ​

​ ​ ​ ​ ​ ​ Additional other ​ ​ ​ Total

​ ​ Common stock ​ paid-in comprehensive ​ Accumulated ​ stockholders’

Restricted stock vesting and issuance, net ​ 915,203 ​ 1 ​ — ​ — ​ — ​ 1

Share-based compensation expense — ​ — ​ 101,636 ​ — ​ — ​ 101,636

Receivable from investor — ​ — ​ ​ 15 ​ ​ — ​ ​ — ​ 15

Comprehensive loss ​ — ​ — ​ — ​ (6,081) ​ — ​ (6,081)

Retired Shares (20) ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ —

Restricted stock vesting and issuance, net 963,543 ​ ​ 1 ​ ​ — ​ ​ — ​ ​ — ​ 1

Share-based compensation expense ​ — ​ ​ — ​ ​ 74,615 ​ ​ — ​ ​ — ​ 74,615

Comprehensive loss ​ — ​ ​ — ​ ​ — ​ ​ (24,601) ​ ​ — ​ (24,601)

Restricted stock vesting and issuance, net 1,254,163 ​ ​ 1 ​ ​ — ​ ​ — ​ ​ — ​ 1

Share-based compensation expense — ​ ​ — ​ ​ 74,547 ​ ​ — ​ ​ — ​ 74,547

Receivable from investor ​ — ​ ​ — ​ ​ 133 ​ ​ — ​ ​ — ​ ​ 133

Comprehensive income — ​ ​ — ​ ​ — ​ ​ 36,387 ​ ​ — ​ 36,387

See accompanying consolidated notes.

​

​

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​

​

PTC Therapeutics, Inc.

Consolidated Statements of Cash Flows

In thousands

​

​

​ ​ ​ ​ ​ ​ ​ ​ ​ ​

​ ​ Year ended December 31,

Cash flows from operating activities ​ ​ ​ ​ ​ ​ ​ ​ ​

Change in valuation of contingent consideration ​ (800) ​ (4,475) ​ (127,700)

Tangible asset impairment ​ ​ 1,018 ​ ​ 4,095 ​ ​ —

Loss on sale of fixed assets ​ ​ 130 ​ ​ 4,298 ​ ​ —

Gain on lease terminations ​ ​ — ​ ​ (2,179) ​ ​ —

Gain on lease modification ​ ​ (10,775) ​ ​ (5,464) ​ ​ —

Gain on sale of priority review voucher ​ ​ — ​ ​ (99,900) ​ ​ —

Realized loss on sale of ClearPoint Equity Investment ​ ​ 7,081 ​ ​ — ​ ​ 782

Realized loss on ClearPoint convertible debt security ​ ​ — ​ ​ 622 ​ ​ —

Non-cash stock consideration, milestone payment ​ ​ — ​ ​ — ​ ​ 29,570

Amortization of discounts on investments, net ​ (18,022) ​ (12,529) ​ (2,200)

Loss on extinguishment of debt ​ ​ — ​ ​ — ​ ​ 55,625

Changes in operating assets and liabilities: ​ ​ ​ ​ ​ ​

Payments on contingent consideration ​ ​ (4,684) ​ ​ (1,800) ​ ​ —

Cash flows from investing activities ​ ​ ​ ​ ​ ​

Proceeds from sale of fixed assets ​ ​ 70 ​ ​ 28,056 ​ ​ —

Proceeds from sale of priority review voucher ​ ​ — ​ ​ 150,000 ​ ​ —

Sale of ClearPoint Equity Investments ​ ​ 12,412 ​ ​ — ​ ​ 2,594

Cash flows from financing activities ​ ​ ​ ​ ​ ​

Proceeds from employee stock purchase plan ​ ​ 5,944 ​ ​ 5,199 ​ ​ 5,954

Repayment of senior secured term loan ​ — ​ — ​ (300,000)

Debt extinguishment costs related to senior secured term loan ​ — ​ — ​ (81,933)

Debt issuance costs related to senior secured term loan ​ ​ — ​ ​ — ​ ​ (282)

Payments on contingent consideration obligation ​ ​ (6,341) ​ ​ (18,200) ​ ​ —

Payment of finance lease principal ​ ​ (1,611) ​ ​ (1,490) ​ ​ (1,379)

Effect of exchange rate changes on cash ​ 22,712 ​ (7,328) ​ 3,114

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Supplemental disclosure of cash information ​ ​ ​ ​ ​ ​

Total income taxes paid, net of refunds received: ​ ​ ​ ​ ​ ​ ​ ​ ​

Federal ​ ​ 26,640 ​ ​ — ​ ​ —

State: ​ ​ ​ ​ ​ ​ ​ ​ ​

Illinois ​ ​ 4,376 ​ ​ — ​ ​ —

Other State ​ ​ 854 ​ ​ — ​ ​ —

Foreign: ​ ​ ​ ​ ​ ​ ​ ​ ​

Brazil ​ ​ 3,143 ​ ​ — ​ ​ —

Other Foreign ​ ​ 1,841 ​ ​ — ​ ​ —

Supplemental disclosure of non-cash investing and financing activity ​ ​ ​ ​ ​ ​

Acquisition of product rights and licenses ​ $ 1,367 ​ $ 420 ​ $ 54,618

Capital expenditures unpaid at the end of the period ​ $ 126 ​ $ 70 ​ $ —

​

See accompanying consolidated notes.

​

​

​

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PTC Therapeutics, Inc.

Notes to consolidated financial statements

December 31, 2025

(In thousands except share and per share amount)

​

1. The Company

PTC Therapeutics, Inc. (the “Company” or “PTC”) is a global biopharmaceutical company dedicated to the discovery, development and commercialization of clinically differentiated medicines for children and adults living with rare disorders. PTC is advancing a robust and diversified pipeline of transformative medicines as part of its mission to provide access to best-in-class treatments for patients with unmet medical needs. PTC’s strategy is to leverage its scientific expertise and global commercial infrastructure to optimize value for its patients and other stakeholders. PTC has a diversified therapeutic portfolio pipeline that includes several commercial products and product candidates in various stages of development, including clinical, pre-clinical and research and discovery stages, focused on the development of new treatments for multiple therapeutic areas for rare diseases relating to neurology and metabolism.

The Company has developed SephienceTM (sepiapterin), a product for the treatment of phenylketonuria (“PKU”), a rare inherited metabolic disease characterized by the body’s inability to break down an essential amino acid called phenylalanine, and which can result in neurological and other symptoms. In June 2025, Sephience was granted marketing authorization by the European Commission (“EC”) for the treatment of children and adults living with PKU within the European Economic Area (“EEA”). In July 2025, Sephience was approved by the U.S. Food and Drug Administration (“FDA”) for the treatment of pediatric and adult patients living with PKU in the United States age one month and above. In December 2025, Sephience was approved by the Japanese Ministry of Health, Labor, and Welfare (“MHLW”) for the treatment of children and adults living with PKU. In February 2026, Sephience was approved by ANVISA, the Brazilian health regulatory authority, for the treatment of children and adults living with PKU in Brazil. Sephience is also approved in additional geographies.

The Company has two products, TranslarnaTM (ataluren) and Emflaza® (deflazacort), for the treatment of Duchenne muscular dystrophy (“DMD”), a rare, life-threatening disorder. While Translarna previously had conditional approval in the EEA, in March 2025, the European Commission, or EC, adopted the negative opinion of the Committee of Medicinal Products for Human Use, or CHMP, of the European Medicines Agency, or EMA, to not renew the conditional marketing authorization of Translarna for the treatment of nmDMD. However, the EC indicated that individual countries within the European Union, or EU, can leverage Articles 117(3) and 5(1) of the EU Directive 2001/83 to allow continued commercial use of Translarna. Translarna has marketing authorization in additional geographies outside of the EEA, but the EC adoption of the CHMP negative opinion may affect future reauthorizations. Emflaza is approved in the United States for the treatment of DMD in patients two years and older.

Translarna is an investigational new drug in the United States. During the first quarter of 2017, the Company filed an NDA for Translarna for the treatment of nmDMD over protest with the FDA. In October 2017, the Office of Drug Evaluation I of the FDA issued a CRL for the NDA, stating that it was unable to approve the application in its current form. In response, the Company filed a formal dispute resolution request with the Office of New Drugs of the FDA. In February 2018, the Office of New Drugs of the FDA denied the Company’s appeal of the CRL. In its response, the Office of New Drugs recommended a possible path forward for the Company’s ataluren NDA submission based on the accelerated approval pathway. The Company followed the FDA’s recommendation and collected, using newer technologies via procedures and methods that the Company designed in a new study, Study 045, and announced the results of Study 045 in February 2021. Study 045 did not meet its pre-specified primary endpoint. In June 2022, the Company announced top-line results from the placebo-controlled trial of Study 041, which was its 18 months, placebo-controlled trial, followed by an 18 months open label extension, of Translarna in the treatment of ambulatory patients with nmDMD aged five years or older. Following this announcement, the Company submitted a meeting request to the FDA to gain clarity on the regulatory pathway for a potential re-submission of an NDA for Translarna. The FDA provided initial written feedback that Study 041 does not provide substantial evidence of effectiveness to support NDA re-submission. The Company held a Type C

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Notes to consolidated financial statements (Continued)

December 31, 2025

(In thousands except share and per share amount)

meeting with the FDA in the fourth quarter of 2023 to discuss the totality of Translarna data. Based on feedback from the FDA, the Company re-submitted the NDA in July 2024, based on the results from Study 041 and from its international drug registry study for nmDMD patients receiving Translarna. In October 2024, the FDA accepted for review the resubmission of the NDA for Translarna for the treatment of nmDMD. Following feedback from FDA at the end of January 2026, the Company decided to withdraw the NDA resubmission for Translarna. Further development of Translarna for the treatment of nmDMD in the United States is not planned.

The Company has developed Upstaza (eladocagene exuparvovec), a gene therapy used for the treatment of Aromatic L-Amino Acid Decarboxylase (“AADC”) deficiency (“AADC deficiency”), a rare central nervous system (“CNS”) disorder arising from reductions in the enzyme AADC that results from mutations in the dopa decarboxylase gene. In July 2022, the EC approved Upstaza for the treatment of AADC deficiency for patients 18 months and older within the EEA. In November 2022, the Medicines and Healthcare Products Regulatory Agency approved Upstaza for the treatment of AADC deficiency for patients 18 months and older within the United Kingdom. In November 2024, the Company’s biologics license application (“BLA”) for its gene therapy treatment of AADC deficiency was approved by the FDA. This gene therapy is marketed under the brand name Kebilidi in the United States.

The Company holds the rights for the commercialization of Tegsedi® (inotersen) and Waylivra® (volanesorsen) for the treatment of rare diseases in countries in Latin America and the Caribbean pursuant to the Collaboration and License Agreement (the “Tegsedi-Waylivra Agreement”), dated August 1, 2018, by and between the Company and Akcea Therapeutics, Inc. (“Akcea”), a subsidiary of Ionis Pharmaceuticals, Inc. Tegsedi has received marketing authorization in the United States, the European Union (the “EU”) and Brazil for the treatment of stage 1 or stage 2 polyneuropathy in adult patients with hereditary transthyretin amyloidosis (“hATTR amyloidosis”). In August 2021, ANVISA, the Brazilian health regulatory authority, approved Waylivra as the first treatment for familial chylomicronemia syndrome (“FCS”) in Brazil. In December 2022, ANVISA approved Waylivra for the treatment of familial partial lipodystrophy (“FPL”). Waylivra has also received marketing authorization in the EU for the treatment of FCS.

The Company also has a spinal muscular atrophy (“SMA”) collaboration with F. Hoffman-La Roche Ltd and Hoffman-La Roche Inc. (referred to collectively as “Roche”) and the Spinal Muscular Atrophy Foundation (“SMA Foundation”). The SMA program has one approved product, Evrysdi® (risdiplam), which was approved by the FDA in August 2020 for the treatment of SMA in adults and children two months and older and by the EC in March 2021 for the treatment of 5q SMA in patients two months and older with a clinical diagnosis of SMA Type 1, Type 2 or Type 3 or with one to four SMN2 copies. Evrysdi has also received marketing authorization for the treatment of SMA in over 100 countries. In May 2022, the FDA approved a label expansion for Evrysdi to include infants under two months old with SMA. In August 2023, the EC approved an extension of the Evrysdi marketing authorization to include infants under two months old in the EU.

In addition to the Company’s SMA program, the Company’s splicing platform also includes votoplam (PTC518), which is being developed for the treatment of Huntington’s disease (“HD”). The Company initiated a Phase 2 study of votoplam for the treatment of HD in the first quarter of 2022, which consisted of an initial 12-week placebo-controlled phase focused on safety, pharmacology and pharmacodynamic effects followed by a nine-month placebo-controlled phase focused on votoplam biomarker effect. In June 2024, the Company announced interim results from the full Phase 2 study of votoplam. At month 12, votoplam treatment demonstrated durable dose-dependent lowering of mutant HTT (“mHTT”) protein in the blood and dose-dependent lowering of mHTT protein in the cerebrospinal fluid in the interim cohort of stage 2 patients. In addition, favorable trends were demonstrated on several relevant HD clinical assessments. Furthermore, following 12 months of treatment, votoplam continued to be well tolerated. In September 2024, the FDA granted Fast Track designation to the votoplam program for the treatment of HD. In December 2024, the Company held a Type C meeting with the FDA to discuss whether huntingtin protein lowering could be considered a surrogate endpoint for

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Notes to consolidated financial statements (Continued)

December 31, 2025

(In thousands except share and per share amount)

accelerated approval of votoplam. The FDA was aligned on the scientific rationale and asked to see additional data supportive of an association between huntingtin protein lowering and changes in clinical outcome scores. In May 2025, the Company announced that the Phase 2 study of votoplam met its primary endpoints of blood HTT lowering and safety. The results on the full study population are consistent with the previously reported evidence of dose-dependent HTT lowering, favorable safety profile and early signals of dose-dependent clinical effect at 12 months in Stage 2 patients. In addition, at 24 months of treatment, there were continued trends of dose-dependent favorable clinical effect relative to a propensity-matched natural history cohort as well as dose-dependent NfL lowering. In November 2024, the Company entered into a License and Collaboration Agreement (the “Novartis Agreement”) with Novartis Pharmaceuticals Corporation (“Novartis”), relating to its votoplam HD program which included related molecules. This transaction closed in January 2025, triggering a $1.0 billion upfront cash payment to the Company. In the fourth quarter of 2025, an End-of-Phase 2 meeting was held with FDA, and alignment was reached on design of a global Phase 3 clinical trial, which the Company expects that Novartis will initiate in the first half of 2026. This trial could serve as the confirmatory study in the context of Accelerated Approval, or as a registration trial. The Company also expects to have results from the Phase 2 PIVOT-HD extension study of votoplam in the first half of 2026, once all participants cross the 24-month time point.

The Company’s inflammation and ferroptosis platform consists of small molecule compounds that target oxidoreductase enzymes that regulate oxidative stress and inflammatory pathways central to the pathology of a number of CNS and non-CNS diseases. The most advanced molecule in the Company’s inflammation and ferroptosis platform is vatiquinone. The Company announced topline results from a registration-directed Phase 3 trial of vatiquinone in children and young adults with Friedreich’s ataxia (“FA”), called MOVE-FA, in May 2023. While the study did not meet its primary endpoint, vatiquinone treatment did demonstrate significant benefit on key disease subscales, including the upright stability subscale, as well as on other disease relevant endpoints. In October 2024, the Company announced that the pre-specified endpoint for two different FA long-term extension studies was met, with statistically significant evidence of durable treatment benefit on disease progression. In December 2024, the Company submitted an NDA to the FDA for vatiquinone for the treatment of children and adults living with FA. In February 2025, the FDA accepted for filing the NDA. In August 2025, the FDA issued a complete response letter related to the NDA stating that substantial evidence of efficacy was not demonstrated for vatiquinone and that an additional adequate and well-controlled study would be needed to support NDA resubmission. The Company met with the FDA in the fourth quarter of 2025 to discuss the vatiquinone development program. FDA suggested an additional study be conducted to support NDA resubmission. FDA stated in the meeting minutes that this study could be an open label study with a natural history control group. The Company plans to meet with FDA in the second quarter of 2026 to discuss the design of this new study.

In addition, the Company has a pipeline of product candidates and discovery programs that are in early clinical, pre-clinical and research and development stages focused on the development of new treatments for multiple therapeutic areas for rare diseases.

As of December 31, 2025, the Company had an accumulated deficit of approximately $2,964.2 million. The Company has financed its operations to date primarily through the private offerings of convertible senior notes (see Note 7), public and “at the market offerings” of common stock, proceeds from royalty purchase agreements (see Note 7), private placements of its convertible preferred stock and common stock, collaborations, bank and institutional lender debt, other convertible debt, grant funding and clinical trial support from governmental and philanthropic organizations and patient advocacy groups in the disease areas addressed by the Company’s product candidates. The Company has also relied on revenue generated from net sales of its products. The Company has also relied on revenue associated with milestone and royalty payments from Roche pursuant to the License and Collaboration Agreement (the “SMA License Agreement”) dated as of November 23, 2011, by and among the Company, Roche and, for the limited purposes set forth therein, the SMA Foundation, under its SMA program. The Company has also relied on revenues associated with the Novartis Agreement. The Company expects that cash flows from the sales of its products, milestone payments from Novartis,

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Notes to consolidated financial statements (Continued)

December 31, 2025

(In thousands except share and per share amount)

together with the Company’s cash, cash equivalents and marketable securities, will be sufficient to fund its operations for at least the next twelve months.

2. Summary of significant accounting policies

Basis of presentation

The accompanying consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles (“GAAP”) and include all adjustments necessary for the fair presentation of the Company’s financial position for the periods presented.

Use of estimates

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Significant estimates in these consolidated financial statements have been made in connection with the calculation of net product sales, royalty revenue, certain accruals related to the Company’s research and development expenses, valuation procedures for liability for sale of future royalties, and the provision for or benefit from income taxes. Actual results could differ from those estimates. Changes in estimates are reflected in reported results in the period in which they become known.

Restricted Cash

Restricted cash included in deposits and other assets on the consolidated balance sheet contains an unconditional, irrevocable and transferable letter of credit of $3.0 million in connection with an amendment and restatement of the Company’s lease in Hopewell Township, New Jersey. Restricted cash also contains an unconditional, irrevocable and transferable letter of credit of $10.0 million in connection with obligations for the Company’s new facility lease in Warren, New Jersey. If after July 1, 2027, the Company is not in default of the lease agreement and meets certain creditworthiness guidelines, then the letter of credit will be reduced to $5.0 million. If after December 31, 2028, the Company is not in default of the lease agreement and meets certain creditworthiness guidelines, then the letter of credit will be further reduced to $2.5 million. Both letters of credit are classified within deposits and other assets on the consolidated balance sheet due to the long-term nature of the letters of credit. Restricted cash also includes a bank guarantee of $0.7 million denominated in a foreign currency.

The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the consolidated balance sheet that sum to the total of the same amounts shown in the statement of cash flows:

​

​ ​ ​ ​ ​ ​ ​

​ ​ ​ ​ End of ​ ​ ​ Beginning of

​ period- period-

​ December 31, December 31,

Restricted cash included in deposits and other assets ​ 13,686 ​ 15,607

​

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Notes to consolidated financial statements (Continued)

December 31, 2025

(In thousands except share and per share amount)

Consolidation

The consolidated financial statements include the accounts of PTC Therapeutics, Inc. and its wholly owned subsidiaries. All inter-company accounts, transactions, and profits have been eliminated in consolidation.

Segment information

Operating segments are defined as components of an enterprise about which separate discrete information is available for evaluation by the chief operating decision maker (“CODM”), or decision-making group, in deciding how to allocate resources and in assessing performance. The Company’s CODM consists of the chief executive officer, the chief financial officer, and the chief business officer. The Company views its operations and manages its business in one operating and reporting segment: life science. The life science segment is focused on the discovery, development and commercialization of the Company’s clinically differentiated medicines that provide benefits to patients with rare disorders. The Company is managed on a consolidated basis, and accordingly, the CODM assesses performance for the life science segment based on net income (loss), with a focus on revenues, research and development expense, and selling general, and administrative expense. Net income (loss) is reported on the income statement as consolidated net income (loss). The measure of segment assets is reported on the balance sheet as total consolidated assets. The Company derives its revenues through its worldwide net sales of its commercial products, collaboration agreements and license agreements, and royalty revenues. Refer to Note 15 for further segment information on revenues.

​

The Company expects to continue to incur significant expenses as it advances product candidates through all stages of development and clinical trials and, ultimately, seek regulatory approval. As such, the CODM uses cash forecast models in deciding how to invest into the life science segment. Such cash forecast models are reviewed to assess the entity-wide operating results and performance. Net income (loss) is used to monitor planned versus actual results. Monitoring planned versus actual results is used in assessing performance of the segment and in establishing management’s compensation, along with the cash forecast models. Refer to Note 15 for segment information on significant segment expenses and geographic breakdown.

​

Cash equivalents

The Company considers all highly liquid investments with a maturity of 90 days or less at the time of purchase to be cash equivalents. Cash equivalents are carried at cost which approximates fair value due to their short-term nature.

Marketable securities

The Company’s marketable securities consists of both debt securities and equity investments. The Company considers its investments in debt securities with original maturities of greater than 90 days to be available for sale securities. Securities under this classification are recorded at fair value and unrealized gains and losses within accumulated other comprehensive income (loss). The estimated fair value of the available for sale securities is determined based on quoted market prices or rates for similar instruments. In addition, the cost of debt securities in this category is adjusted for amortization of premium and accretion of discount to maturity. For available for sale debt securities in an unrealized loss position, the Company assesses whether it intends to sell or if it is more likely than not that the Company will be required to sell the security before recovery of its amortized cost basis. If either of the criteria regarding intent or requirement to sell is met, the security’s amortized cost basis is written down to fair value. If the criteria are not met, the Company evaluates whether the decline in fair value has resulted from a credit loss or other factors. In making this assessment, management considers, among other factors, the extent to which fair value is less than amortized cost, any changes to the rating of the security by a rating agency, and adverse conditions specifically related to the security. If this assessment

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Notes to consolidated financial statements (Continued)

December 31, 2025

(In thousands except share and per share amount)

indicates that a credit loss exists, the present value of cash flows expected to be collected from the security are compared to the amortized cost basis of the security. If the present value of the cash flows expected to be collected is less than the amortized cost basis, a credit loss exists and an allowance for credit losses is recorded for the credit loss, limited by the amount that the fair value is less than the amortized costs basis. Any impairment that has not been recorded through an allowance for credit losses is recognized in other comprehensive income. For the years ended December 31, 2025 and 2024, no allowance was recorded for credit losses.

Marketable securities that are equity investments are measured at fair value, as it is readily available, and as such are classified as Level 1 assets. Unrealized holding gains and losses for these equity investments are components of other (expense) income, net within the consolidated statement of operations.

Concentration of credit risk

The Company’s financial instruments that are exposed to credit risks consist primarily of cash and cash equivalents, available-for-sale marketable securities and accounts receivable. The Company maintains its cash and cash equivalents in bank accounts, which, at times, exceed federally insured limits. The Company has not experienced any credit losses in these accounts and does not believe it is exposed to any significant credit risk on these funds. The Company’s investment policy includes guidelines on the quality of the financial institutions and financial instruments the Company is allowed to invest in, which the Company believes minimizes the exposure to concentration of credit risk.

The Company is subject to credit risk from its accounts receivable related to its product sales. The payment terms are predetermined and the Company evaluates the creditworthiness of each customer or distributor on a regular basis. The Company reserves all uninsured amounts billed directly to a patient until the time of cash receipt as collectability is not reasonably assured at the time the product is received. To date, the Company has not incurred any material credit losses.

Fixed assets

Fixed assets are stated at cost. Depreciation is computed starting when the asset is placed into service on a straight-line basis over the estimated useful life of the related asset as follows:

​

Leasehold improvements ​ ​ Lesser of useful life or remaining lease term

Computer equipment and software ​ 3 years

Machinery and lab equipment ​ 7 years

Furniture and fixtures ​ 7 years

​

Inventory and cost of product sales

Inventory

Inventories are stated at the lower of cost and net realizable value, utilizing standard costing, which approximates average costs by product. The Company capitalizes inventory costs associated with products following regulatory approval when future commercialization is considered probable and the future economic benefit is expected to be realized. Products which may be used in clinical development programs are included in inventory and charged to research and development expense when the product enters the research and development process and no longer can be used for commercial purposes. Inventory used for marketing efforts are charged to selling, general and administrative expense. Amounts related to clinical development programs and marketing efforts are immaterial.

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Notes to consolidated financial statements (Continued)

December 31, 2025

(In thousands except share and per share amount)

The following table summarizes the components of the Company’s inventory for the periods indicated:

​

​ ​ ​ ​ ​ ​ ​

​

The Company periodically reviews its inventories for excess amounts or obsolescence and writes down obsolete or otherwise unmarketable inventory to its estimated net realizable value. The Company recorded write downs of $5.2 million and $13.2 million for the years ended December 31, 2025 and 2024, respectively, primarily related to adjustments to inventory reserves and product approaching expiration. Additionally, though the Company’s product is subject to strict quality control and monitoring which it performs throughout the manufacturing processes, certain batches or units of product may not meet quality specifications resulting in a charge to cost of product sales. For the years ended December 31, 2025 and December 31, 2024, these amounts were immaterial.

Cost of product, collaboration and license sales

Cost of product, collaboration and license sales consists of the cost of inventory sold, manufacturing and supply chain costs, storage costs, amortization of the acquired intangible asset, royalty payments associated with net product sales, royalty payments to collaborative partners associated with royalty revenues and collaboration revenue related to milestones, and costs related to performance of services associated with license agreement revenues. Production costs are expensed as cost of product, collaboration and license sales when the related products are sold or royalty revenues and collaboration revenue milestones are earned.

Accumulated other comprehensive income (loss)

Accumulated other comprehensive income (loss) consists of unrealized gains or losses on marketable securities and foreign currency translation adjustments.

Revenue recognition

Net product revenue

The Company’s net product revenue primarily consists of sales of Translarna in territories outside of the U.S. for the treatment of nmDMD and sales of Emflaza in the U.S. for the treatment of DMD. Beginning in the second half of 2025, net product revenues also includes Sephience for the treatment of PKU. The Company recognizes revenue when its performance obligations with its customers have been satisfied. The Company’s performance obligations are to provide products based on customer orders from distributors, hospitals, specialty pharmacies or retail pharmacies. The performance obligations are satisfied at a point in time when the Company’s customer obtains control of the product, which is typically upon delivery. The Company invoices its customers after the products have been delivered and invoice payments are generally due within 30 to 90 days of the invoice date. The Company determines the transaction price based on fixed consideration in its contractual agreements. Contract liabilities arise in certain circumstances when consideration is due for goods the Company has yet to provide. As the Company has identified only one distinct performance obligation, the transaction price is allocated entirely to product sales. In determining the transaction price, a significant financing component does not exist since the timing from when the Company delivers product to when the customers pay for the

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Notes to consolidated financial statements (Continued)

December 31, 2025

(In thousands except share and per share amount)

product is typically less than one year. Customers in certain countries pay in advance of product delivery. In those instances, payment and delivery typically occur in the same month.

The Company records product sales net of any variable consideration, which includes discounts, allowances, rebates related to Medicaid and other government pricing programs, and distribution fees. The Company uses the expected value or most likely amount method when estimating its variable consideration, unless discount or rebate terms are specified within contracts. The identified variable consideration is recorded as a reduction of revenue at the time revenues from product sales are recognized. These estimates for variable consideration are adjusted to reflect known changes in factors and may impact such estimates in the quarter those changes are known. Revenue recognized does not include amounts of variable consideration that are constrained.

In relation to customer contracts, the Company incurs costs to fulfill a contract but does not incur costs to obtain a contract. These costs to fulfill a contract do not meet the criteria for capitalization and are expensed as incurred. The Company considers any shipping and handling costs that are incurred after the customer has obtained control of the product as a cost to fulfill a promise. Shipping and handling costs associated with finished goods delivered to customers are recorded as a selling expense.

Collaboration, license, and royalty revenue

The terms of these agreements typically include payments to the Company of one or more of the following: nonrefundable, upfront license fees; milestone payments; research funding and royalties on future product sales. In addition, the Company generates service revenue through agreements that generally provide for fees for research and development services and may include additional payments upon achievement of specified events.

At the inception of a collaboration arrangement, the Company needs to first evaluate if the arrangement meets the criteria in Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 808 “Collaborative Arrangements” to then determine if ASC Topic 606 is applicable by considering whether the collaborator meets the definition of a customer. If the criteria are met, the Company assesses the promises in the arrangement to identify distinct performance obligations.

For licenses of intellectual property, the Company assesses, at contract inception, whether the intellectual property is distinct from other performance obligations identified in the arrangement. If the licensing of intellectual property is determined to be distinct, revenue is recognized for nonrefundable, upfront license fees when the license is transferred to the customer and the customer can use and benefit from the license. If the licensing of intellectual property is determined not to be distinct, then the license will be bundled with other promises in the arrangement into one distinct performance obligation. The Company needs to determine if the bundled performance obligation is satisfied over time or at a point in time. If the Company concludes that the nonrefundable, upfront license fees will be recognized over time, the Company will need to assess the appropriate method of measuring proportional performance.

For milestone payments, the Company assesses, at contract inception, whether the development or sales-based milestones are considered probable of being achieved. If it is probable that a significant revenue reversal will occur, the Company will not record revenue until the uncertainty has been resolved. Milestone payments that are contingent upon regulatory approval are not considered probable of being achieved until the applicable regulatory approvals or other external conditions are obtained as such conditions are not within the Company’s control. If it is probable that a significant revenue reversal will not occur, the Company will estimate the milestone payments using the most likely amount method. The Company will re-assess the development and sales-based milestones each reporting period to determine the probability of achievement. The Company recognizes royalties from product sales at the later of when the related sales occur or when

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December 31, 2025

(In thousands except share and per share amount)

the performance obligation to which the royalty has been allocated has been satisfied. If it is probable that a significant revenue reversal will not occur, the Company will estimate the royalty payments using the most likely amount method.

The Company recognizes revenue for reimbursements of research and development costs under collaboration agreements as the services are performed. The Company records these reimbursements as revenue and not as a reduction of research and development expenses as the Company has the risks and rewards as the principal in the research and development activities.

Translarna France

​

During the year ended December 31, 2025, the Company changed its estimates for its sales allowance related to Translarna revenues in France, primarily based on its recent communications with the French pricing authorities subsequent to the EC’s adoption of the opinion of the CHMP of the EMA to not renew the authorization of Translarna for the treatment of nmDMD. This change in estimate resulted in an increase of $98.6 million to the sales allowance reserve, which is recorded within the accounts payable and accrued expenses line on the consolidated balance sheets for the period ended December 31, 2025, and a decrease to net product revenues of $98.6 million, which is recorded to the Translarna France line item on the consolidated statement of operations for the year ended December 31, 2025. The $98.6 million change in sales allowance estimate represents a life to date adjustment for the historical sales of Translarna in France. Translarna France revenues were reclassified from net product revenues to the Translarna France line item on the consolidated statement of operations for the years ended December 31, 2024 and December 31, 2023 to allow revenue for Translarna France to be comparable.

Allowance for doubtful accounts