PTC THERAPEUTICS, INC.

Previous wording

Sephience (sepiapterin) is a product for the treatment of phenylketonuria, or PKU, a rare inherited metabolic disease which affects the brain. On July 28, 2025, Sephience was approved by the FDA for the treatment of pediatric and adult patients living with PKU in the United States. On June 19, 2025, Sephience was granted marketing authorization by the EC for the treatment of children and adults living with PKU within the EEA. We also made a regulatory submission for Sephience for the treatment of PKU in Brazil in the third quarter of 2024, with a regulatory decision expected in the second half of 2025, and in Japan in the fourth quarter of 2024, with a regulatory decision expected in the fourth quarter of 2025.

Current wording

Sephience (sepiapterin) is 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. On July 28, 2025, Sephience was approved by the U.S. Food and Drug Administration, or the FDA, for the treatment of pediatric and adult patients living with PKU in the United States age one month and above. On June 19, 2025, Sephience was granted marketing authorization by the European Commission, or the EC, for the treatment of children and adults living with PKU within the European Economic Area, or the EEA. We also made regulatory submissions for Sephience for the treatment of PKU in Brazil in the third quarter of 2024, and in Japan in the fourth quarter of 2024, with regulatory decisions expected in the fourth quarter of 2025. During the quarter ended September 30, 2025, we recognized $19.6 million in net sales of Sephience.

Previous wording

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

Current wording

On August 5, 2025, we, certain of the former securityholders of Censa, and, for the limited purposes set forth in the agreement, Shareholder Representative Services LLC, a Colorado limited liability company, entered into a Rights Satisfaction Agreement, or the Rights Satisfaction Agreement, pursuant to which such former securityholders of Censa, or 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 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, Censa and, solely in its capacity as the representative, agent and attorney-in-fact of the securityholders of Censa, Shareholder Representative Services LLC, in exchange for the consideration set forth in the Rights Satisfaction Agreement and further detailed below.

Previous wording

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 a percentage of annual net sales during the applicable payment term equal to (i) 8% of annual Net Sales of Product for that portion of annual Net Sales of Product less than or equal to $250.0 million, (ii) 10% of annual Net Sales of Product for that portion of annual Net Sales of Product greater than

Current wording

term equal to (i) 8% of annual Net Sales of Product for that portion of annual Net Sales of Product less than or equal to $250.0 million, (ii) 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 (iii) 12% of annual Net Sales of Product for that portion of annual Net Sales of Product greater than $500.0 million, which we refer to collectively as the Net Sales Payments.

Previous wording

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 approximately $225.0 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, after the Closing, 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.

Current wording

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, after the Closing, 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.

Previous wording

We have two products, Translarna™ (ataluren) and Emflaza® (deflazacort), for the treatment of Duchenne muscular dystrophy, or DMD, a rare, life-threatening disorder. Translarna has marketing authorization in Russia for the treatment of nonsense mutation Duchenne muscular dystrophy, or nmDMD, in patients aged two years and older, and in Brazil for the treatment of nmDMD in ambulatory patients two years and older and for continued treatment of patients that become non-ambulatory, as well as in various other countries. During the quarter ended June 30, 2025, we recognized $59.5 million in net sales of Translarna. We hold worldwide commercialization rights to Translarna for all indications in all territories.

Current wording

We have two products, Translarna™ (ataluren) and Emflaza® (deflazacort), for the treatment of Duchenne muscular dystrophy, or DMD, a rare, life-threatening disorder. Translarna has marketing authorization in Russia for the treatment of nonsense mutation Duchenne muscular dystrophy, or nmDMD, in patients aged two years and older, and in Brazil for the treatment of nmDMD in ambulatory patients two years and older and for continued treatment of patients that become non-ambulatory, as well as in various other countries. During the quarter ended September 30, 2025, we recognized $50.7

Previous wording

Emflaza is approved in the United States for the treatment of DMD in patients two years and older. During the quarter ended June 30, 2025, we recognized $36.4 million in net sales of Emflaza.

Current wording

million in net sales of Translarna. We hold worldwide commercialization rights to Translarna for all indications in all territories. Emflaza is approved in the United States for the treatment of DMD in patients two years and older. During the quarter ended September 30, 2025, we recognized $35.2 million in net sales of Emflaza.

Previous wording

We previously had a marketing authorization for Translarna in the European Economic Area, or EEA, which had been subject to annual review and renewal by the European Commission, or EC, following reassessment by the European Medicines Agency, or EMA, of the benefit-risk balance of the authorization. In September 2022, we submitted a Type II variation to the EMA to support conversion of the conditional marketing authorization for Translarna to a standard marketing authorization, which included a report on the placebo-controlled trial of Study 041 and data from the open-label extension as further described below. Study 041 was an 18-month, placebo-controlled trial, followed by an 18-month open-label extension of Translarna in the treatment of ambulatory patients with nmDMD aged five years or older. In February 2023, we also submitted an annual marketing authorization renewal request to the EMA. In September 2023, the Committee for Medicinal Products for Human Use, or CHMP, gave a negative opinion on the conversion of the conditional marketing authorization to full marketing authorization of Translarna for the treatment of nmDMD and a negative opinion on the renewal of the existing conditional marketing authorization of Translarna for the treatment of nmDMD. In January 2024, the CHMP issued a negative opinion for the renewal of the conditional marketing authorization following a re-examination procedure. In May 2024, the EC decided not to adopt the CHMP’s negative opinion for the renewal of the conditional marketing authorization of Translarna and returned such opinion to the CHMP for re-evaluation. In June 2024, following the EC’s request for re-review, the CHMP issued a negative opinion on the renewal of the conditional marketing authorization of Translarna for the treatment of nmDMD. In October 2024, the CHMP maintained its negative opinion for the renewal of the conditional marketing authorization following the requested reexamination procedure. In March 2025, the EC adopted the opinion of the CHMP to not renew the 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. 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.

Current wording

We previously had a marketing authorization for Translarna in the EEA, which had been subject to annual review and renewal by the EC, following reassessment by the European Medicines Agency, or EMA, of the benefit-risk balance of the authorization. In September 2022, we submitted a Type II variation to the EMA to support conversion of the conditional marketing authorization for Translarna to a standard marketing authorization, which included a report on the placebo-controlled trial of Study 041 and data from the open-label extension as further described below. Study 041 was an 18-month, placebo-controlled trial, followed by an 18-month open-label extension of Translarna in the treatment of ambulatory patients with nmDMD aged five years or older. In February 2023, we also submitted an annual marketing authorization renewal request to the EMA. In September 2023, the Committee for Medicinal Products for Human Use, or CHMP, gave a negative opinion on the conversion of the conditional marketing authorization to full marketing authorization of Translarna for the treatment of nmDMD and a negative opinion on the renewal of the existing conditional marketing authorization of Translarna for the treatment of nmDMD. In January 2024, the CHMP issued a negative opinion for the renewal of the conditional marketing authorization following a re-examination procedure. In May 2024, the EC decided not to adopt the CHMP’s negative opinion for the renewal of the conditional marketing authorization of Translarna and returned such opinion to the CHMP for re-evaluation. In June 2024, following the EC’s request for re-review, the CHMP issued a negative opinion on the renewal of the conditional marketing authorization of Translarna for the treatment of nmDMD. In October 2024, the CHMP maintained its negative opinion for the renewal of the conditional marketing authorization following the requested reexamination procedure. In March 2025, the EC adopted the opinion of the CHMP to not renew the 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. 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.

Previous wording

Translarna is an investigational new drug in the United States. During the first quarter of 2017, we filed a New Drug Application, or NDA, for Translarna for the treatment of nmDMD over protest with the United States Food and Drug Administration, or FDA. In October 2017, the Office of Drug Evaluation I of the FDA issued a Complete Response Letter, or CRL, 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 CRL. In its response, the Office of New Drugs recommended a possible path forward for the ataluren NDA submission based on the accelerated approval pathway. This would involve a resubmission of an NDA containing the current data on effectiveness of ataluren with new data to be generated on dystrophin production in nmDMD patients’ muscles. We followed the FDA’s recommendation and collected, using newer technologies via procedures and methods that we designed, such dystrophin data 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. Following this announcement, we submitted a meeting request to the FDA to gain clarity on the regulatory pathway for a potential resubmission of an NDA for Translarna. The FDA provided initial written feedback that Study 041 does not provide substantial evidence of effectiveness to support an NDA resubmission. 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 resubmitted 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. As this was an NDA resubmission following a complete response letter to the NDA which was filed over protest in 2016, the FDA is not obligated to follow the review timelines under Prescription Drug User Fee Act guidelines and an action date has not been provided.

Current wording

Translarna is an investigational new drug in the United States. During the first quarter of 2017, we filed a New Drug Application, or 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, or CRL, 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 CRL. In its response, the Office of New Drugs recommended a possible path forward for the ataluren NDA submission based on the accelerated approval pathway. This would involve a resubmission of an NDA containing the current data on effectiveness of ataluren with new data to be generated on dystrophin production in nmDMD patients’ muscles. We followed the FDA’s recommendation and collected, using newer technologies via procedures and methods that we designed, such dystrophin data 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. Following this announcement, we submitted a meeting request to the FDA to gain clarity on the regulatory pathway for a potential resubmission of an NDA for Translarna. The FDA provided initial written feedback that Study 041 does not provide substantial evidence of effectiveness to support an NDA resubmission. 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 resubmitted 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. As this was an NDA resubmission following a complete response letter to the NDA which was filed over protest in 2016, the FDA is not obligated to follow the review timelines under Prescription Drug User Fee Act guidelines, and an action date has not been provided.

Previous wording

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, European Union, or 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.

Current wording

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.

Previous wording

In addition to our SMA program, our splicing platform also includes votoplam (PTC518), 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 consists 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, we announced interim results from the full Phase 2 study ofvotoplam. At month 12, votoplam treatment demonstrated durable dose-dependent lowering of 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, we held a Type C meeting with the FDA to discuss whether huntingtin protein lowering could be considered a surrogate endpoint for 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, 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,

Current wording

In addition to our SMA program, our splicing platform also includes votoplam (PTC518), 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 June 2024, we announced interim results from the full Phase 2 study ofvotoplam. At month 12, votoplam treatment demonstrated durable dose-dependent lowering of 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, we held a Type C meeting with the FDA to discuss whether huntingtin protein lowering could be considered a surrogate endpoint for 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, 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

Previous wording

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, we entered into the License and Collaboration Agreement, or the Novartis Agreement, with Novartis Pharmaceuticals Corporation, or Novartis, relating to our votoplam program. This transaction closed in January 2025. Pursuant to the Novartis Agreement, we are responsible for completing the ongoing Phase 2A clinical trial and continuing the ongoing open label extension, or OLE, clinical trial pursuant to its existing development plan, with the goal of transitioning the ongoing OLE clinical trial to Novartis within 12 months after the effective date of the Novartis Agreement. 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. We continue to collaborate with Novartis on next steps and aim to meet with FDA in the fourth quarter of 2025 to discuss Phase 3 clinical trial design and potential accelerated approval pathway.

Current wording

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, we entered into the License and Collaboration Agreement, or the Novartis Agreement, with Novartis Pharmaceuticals Corporation, or Novartis, relating to our votoplam program. This transaction closed in January 2025. Pursuant to the Novartis Agreement, we were responsible for completing the ongoing Phase 2A clinical trial and continuing the ongoing open label extension, or OLE, clinical trial pursuant to its existing development plan, with the goal of transitioning the ongoing OLE clinical trial to Novartis within 12 months after the effective date of the Novartis Agreement. As of September 30, 2025, these were considered substantially complete. 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. We continue to collaborate with Novartis on next steps and aim to meet with FDA in the fourth quarter of 2025 to discuss Phase 3 clinical trial design and potential accelerated approval pathway.

Previous wording

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 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, called MOVE-FA, in May 2023. While the study did not meet its primary endpoint of statistically significant change in modified Friedreich Ataxia Rating Scale, or mFARS, score at 72 weeks in the primary analysis population, vatiquinone treatment did demonstrate significant benefit on key disease subscales and secondary endpoints. In addition, in the population of subjects that completed the study protocol, significance was reached in the mFARS endpoint and several secondary endpoints, including the upright stability subscale. Furthermore, vatiquinone was well tolerated. 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 February 2025, the FDA accepted for filing the NDA and granted priority review with a target regulatory action date of August 19, 2025.

Current wording

Our inflammation and ferroptosis platform consists of small molecule compounds that target key 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, called MOVE-FA, in May 2023. While the study did not meet its primary endpoint of statistically significant change in modified Friedreich Ataxia Rating Scale, or mFARS, score at 72 weeks in the primary analysis population, vatiquinone treatment did demonstrate significant benefit on key disease subscales and secondary endpoints. In addition, in the population of subjects that completed the study protocol, significance was reached in the mFARS endpoint and several secondary endpoints, including the upright stability subscale. Furthermore, vatiquinone was well tolerated. 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 plan to meet with the FDA in the fourth quarter to discuss the vatiquinone development program.

Previous wording

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. Our revenues are primarily generated from sales of 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 early access programs, or EAP, programs or through similar styled programs, and from sales of Emflaza for the treatment of DMD in the United States. We also generate revenue from sales of Upstaza for the treatment of AADC deficiency in the EEA, we 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 already completed pursuant to the Novartis Agreement.

Current wording

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. Our revenues are primarily generated from sales of Translarna 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 early access programs, or EAP, programs or through similar styled programs, and from sales of Emflaza for the treatment of DMD in the United States. Beginning in the three months ended September 30, 2025, our revenues are also generated from sales of Sephience for the treatment of PKU in the United States and in territories outside of the United States. We also generate revenue from sales of Upstaza/Kebilidi for the treatment of AADC deficiency based on regulatory approvals in the EEA and the United States, we 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 already completed pursuant to the Novartis Agreement.

Previous wording

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 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 area addressed by our product candidates. We have relied on revenue generated from net sales of Translarna for the treatment of nmDMD in territories outside of the United States since 2014, Emflaza for the treatment of DMD in the United States since 2017 and Upstaza for the treatment of AADC deficiency in the EEA since 2022. We have also relied

Current wording

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 convertible preferred stock and common stock, collaborations, bank and institutional lender debt, other convertible debt, grant funding

Previous wording

on revenue associated with milestone and royalty payments from Roche pursuant to the SMA License Agreement under our SMA program, revenue generated from net sales of Tegsedi and Waylivra in Latin America and the Caribbean, and license revenues related to performance obligations already completed pursuant to the Novartis Agreement.

Current wording

and clinical trial support from governmental and philanthropic organizations and patient advocacy groups in the disease area 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, revenue generated from net sales of Tegsedi and Waylivra in Latin America and the Caribbean, and license revenues related to performance obligations already completed pursuant to the Novartis Agreement.

Previous wording

In November 2024, we entered into the Novartis Agreement relating to our votoplam HD program which includes related molecules. Pursuant to the Novartis Agreement, we are responsible for completing the ongoing Phase 2A clinical trial and continuing the ongoing OLE clinical trial pursuant to its existing development plan, with the goal of transitioning the ongoing OLE clinical trial to Novartis within 12 months after the effective date. 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.

Current wording

In November 2024, we entered into the Novartis Agreement relating to our votoplam HD program which includes related molecules. Pursuant to the Novartis Agreement, we were responsible for completing the ongoing Phase 2A clinical trial and continuing the ongoing OLE clinical trial pursuant to its existing development plan, with the goal of transitioning the ongoing OLE clinical trial to Novartis within 12 months after the effective date. As of September 30, 2025, these were considered substantially complete. 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.

Previous wording

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. During the three and six months ended June 30, 2025, we did not issue or sell any shares of common stock pursuant to the Sales Agreement. 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 June 30, 2025.

Current wording

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. During the three and nine months ended September 30, 2025, we did not issue or sell any shares of common stock pursuant to the Sales Agreement. 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 September 30, 2025.

Previous wording

As of June 30, 2025, we had an accumulated deficit of $2,845.2 million. We had a net income of $801.7 million and a net loss of $190.8 million for the six months ended June 30, 2025 and 2024, respectively.

Current wording

As of September 30, 2025, we had an accumulated deficit of $2,829.3 million. We had a net income of $817.6 million and a net loss of $297.4 million for the nine months ended September 30, 2025 and 2024, respectively.

Previous wording

Weanticipate that we will continue to incur significant expenses in connection with our commercialization efforts in the United States, the EEA, Latin America 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. We continue to seek marketing authorization for Translarna for the treatment of nmDMD in territories in which we do not currently have marketing authorization. We have submittedan NDA to the FDA for vatiquinione for the treatment of FA in the fourth quarter of 2024. These efforts may significantly impact the timing and extent of our commercialization and manufacturing expenses.

Current wording

Weanticipate that we will continue to incur significant expenses in connection with our commercialization efforts in the United States, the EEA, Latin America 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. We continue to seek marketing authorization for Translarna for the treatment of nmDMD and Sephiencefor

Previous wording

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.

Current wording

We will need to generate significant revenues to 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.

Previous wording

*Net product 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. We recognize revenue when performance obligations with customers have been satisfied and if it is probable that a significant revenue reversal will not occur. 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.

Current wording

*Net product 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, sales of Emflaza for the treatment of DMD in the United States. Beginning in the three months ended September 30, 2025, net product revenues also includes Sephience for the treatment of PKU. We recognize revenue when performance obligations with customers have been satisfied and if it is probable that a significant revenue reversal will not occur. 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.

Previous wording

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

Current wording

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

Previous wording

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.

Current wording

such estimates in the quarter those changes are known. Revenue recognized does not include amounts of variable consideration that are constrained.

Previous wording

During the three and six months ended June 30, 2025 and 2024, net product revenues consisted of the following:

Current wording

During the three and nine months ended September 30, 2025 and 2024, net product revenues consisted of the following:

Previous wording

Disaggregated net product revenues by country for the three and six months ended June 30, 2025 and 2024 are as follows:

Current wording

Disaggregated net product revenues by country for the three and nine months ended September 30, 2025 and 2024, are as follows:

Previous wording

For the three months ended June 30, 2025, three of our distributors each accounted for over 10% of our net product sales. For the three months ended June 30, 2024, two of our distributors each accounted for over 10% of our net product sales. For the six months ended June 30, 2025 and 2024, two of our distributors each accounted for over 10% of our net product sales.

Current wording

For the three months ended September 30, 2025, four of our distributors each accounted for over 10% of our net product sales. For the three months ended September 30, 2024, two of our distributors each accounted for over 10% of our net product sales. For the nine months ended September 30, 2025, three of our distributors each accounted for over 10% of our net product sales. For the nine months ended September 30, 2024, two of our distributors each accounted for over 10% of our net product sales.

Previous wording

*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 June 30, 2025, we had recognized a total of $310.0 million in

Current wording

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 September 30, 2025, we had recognized a total of $310.0 million in milestone payments and $710.4 million royalties on net sales pursuant to the SMA License Agreement. As of September 30, 2025, there are no remaining research and development event milestones that we can receive. The remaining potential sales milestones as of September 30, 2025 are $150.0 million upon achievement of certain sales events.

Previous wording

For the three and six months ended June 30, 2025, collaboration revenue related to the SMA License Agreement with Roche was immaterial. For the three and six months ended June 30, 2024, we did not recognize collaboration revenue related to the SMA License Agreement with Roche.

Current wording

For the three and nine months ended September 30, 2025, collaboration revenue related to the SMA License Agreement with Roche was immaterial. For the three and nine months ended September 30, 2024, we did not recognize collaboration revenue related to the SMA License Agreement with Roche.

Previous wording

For the three and six months ended June 30, 2025, we recognized $57.6 million and $94.0 million of royalty revenue, respectively, related to Evrysdi. For the three and six months ended June 30, 2024, we recognized $53.2 million and $84.3 million of royalty revenue, respectively, related to Evrysdi.

Current wording

For the three and nine months ended September 30, 2025, we recognized $70.8 million and $164.8 million of royalty revenue, respectively, related to Evrysdi. For the three and nine months ended September 30, 2024, we recognized $61.4 million and $145.7 million of royalty revenue, respectively, related to Evrysdi.

Previous wording

During the three and six months ended June 30, 2025, we recognized $2.9 million and $992.7 million, respectively, in license revenues related to performance obligations for Novartis already completed. The remaining $7.3 million is recorded as deferred revenue on the consolidated balance sheet as of June 30, 2025 and will be recognized over time as the work related to the OLE clinical trial is performed. Collaboration and license revenue during the six months ended June 30, 2025 was partially offset by $3.5 million related to a refund for a prior collaboration arrangement in relation to votoplam.

Current wording

During the three and nine months ended September 30, 2025, we recognized $9.3 million and $1.0 billion in license revenues, respectively, related to Novartis. As all performance obligations are considered to be substantially complete, there is no remaining deferred revenue on the consolidated balance sheet as of September 30, 2025. Collaboration and license revenue during the nine months ended September 30, 2025 was partially offset by $3.5 million related to a refund for a prior collaboration arrangement in relation to votoplam.

Previous wording

The following tables provides research and development expense for our most advanced principal product development programs, for the three and six months ended June 30, 2025 and 2024.

Current wording

The following tables provides research and development expense for our most advanced principal product development programs, for the three and nine months ended September 30, 2025 and 2024.

Previous wording

For the three and six months ended June 30, 2025, compared to the three and six months ended June 30, 2024, 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.

Current wording

For the three and nine months ended September 30, 2025, compared to the three and nine months ended September 30, 2024, 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.

Previous wording

For the three and six months ended June 30, 2025, compared to the three and six months ended June 30, 2024, the decrease in research expenses primarily reflected our continued focus of our resources on product candidates approaching approval during the current year periods.

Current wording

For the three and nine months ended September 30, 2025, compared to the three and nine months ended September 30, 2024, the decrease in research expenses primarily reflected our continued focus of our resources on product candidates approaching approval during the current year periods.

Previous wording

For the three and six months ended June 30, 2025, compared to the three and six months ended June 30, 2024, the decrease in milestone expenses related to the achievement of a $15.0 million success-based regulatory milestone for the validation and acceptance of a marketing authorization application for sepiapterin for PKU in May 2024.

Current wording

For the three and nine months ended September 30, 2025, compared to the three and nine months ended September 30, 2024, the decrease in milestone expenses related to the achievement of a total of $65.0 million regulatory success-based milestones paid to the former Censa securityholders for the nine months ended September 30, 2024.

Previous wording

For the three and six months ended June 30, 2025 compared to the three and six months ended June 30, 2024, the change in payroll, benefits, and share-based stock compensation expenses was relatively flat.

Current wording

For the three and nine months ended September 30, 2025, compared to the three and nine months ended September 30, 2024, the change in payroll, benefits, and share-based stock compensation expenses was relatively flat.

Previous wording

For the three and six months ended June 30, 2025 compared to the three and six months ended June 30, 2024, the decrease 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 in June 2024 and at our facility in Warren, New Jersey as a result of an amendment to our lease for such facility in December 2024.

Current wording

For the three months ended September 30, 2025, compared to the three months ended September 30, 2024, the change in facilities and other expenses was relatively flat. For the nine months ended September 30, 2025 compared to the nine months ended September 30, 2024, the decrease 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 in June 2024 and at our facility in Warren, New Jersey as a result of an amendment to our lease for such facility in December 2024.

Previous wording

During the three and six months ended June 30, 2025, there were no material changes to our critical accounting policies as reported in our 2024 Annual Report.

Current wording

During the three and nine months ended September 30, 2025, there were no material changes to our critical accounting policies as reported in our 2024 Annual Report.

Previous wording

Net product revenue. Net product revenue was $118.3 million for the three months ended June 30, 2025, a decrease of $14.9 million, or 11%, from $133.2 million for the three months ended June 30, 2024. The decrease in net product revenue was primarily due to a decrease in net product sales of Emflaza and Translarna. Emflaza net product revenue was $36.4 million for the three months ended June 30, 2025, a decrease of $10.9 million, or 23%, compared to $47.3 million for the three months ended June 30, 2024. These results were driven by additional generic competition. Translarna net product revenues were $59.5 million for the three months ended June 30, 2025, a decrease of $10.9 million, or 15%, compared to $70.4 million for the three months ended June 30, 2024. These results were primarily due to the EC’s adoption of the CHMP’s negative opinion.

Current wording

Net product revenue. Net product revenue was $131.0 million for the three months ended September 30, 2025, a decrease of $4.5 million, or 3%, from $135.4 million for the three months ended September 30, 2024. The decrease in net product revenue was primarily due to a decrease in net product sales of Emflaza and Translarna, partially offset by an increase in net product sales of Kebilidi/Upstaza and Sephience due to the timing of approvals for those products. 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.

Previous wording

Collaboration and license revenue*.* Collaboration and license revenue was $2.9 million for the three months ended June 30, 2025, an increase of $2.9 million, or 100%, from $0.0 million for the three months ended June 30, 2024. The increase in collaboration and license revenue was due to the receipt of the $1.0 billion upfront payment upon the effective

Current wording

Collaboration and license revenue*.* Collaboration and license revenue was $9.3 million for the three months ended September 30, 2025, an increase of $9.3 million, or 100%, from $0.0 million for the three months ended

Previous wording

date of the license and collaboration agreement with Novartis related to our votoplam HD program. For the three months ended June 30, 2025, we recognized $2.9 million related to license revenue from the Novartis Agreement for performance obligations completed during the period. For the three months ended June 30, 2024, we did not recognize any collaboration or license revenue.

Current wording

September 30, 2024. For the three months ended September 30, 2025, we recognized $9.3 million related to license revenue from the Novartis Agreement for performance obligations completed during the period. For the three months ended September 30, 2024, we did not recognize any collaboration or license revenue.