Commitments and contingencies	9 Months Ended
Sep. 30, 2025
Commitments and Contingencies Disclosure [Abstract]
Commitments and contingencies	10. Commitments and contingencies Under various agreements, the Company will be required to pay royalties and milestone payments upon the successful development and commercialization of products. Pursuant to the Agreement and Plan of Merger (the “Agilis Merger Agreement”), dated as of July 19, 2018 by and among the Company, Agilis Biotherapeutics, Inc. (“Agilis”) and Agility Merger Sub, Inc. (such merger pursuant thereto, the “Agilis Merger”), Agilis equityholders were previously entitled to receive contingent consideration payments from the Company based on (i) the achievement of certain development milestones up to an aggregate maximum amount of $60.0 million, (ii) the achievement of certain regulatory approval milestones together with a milestone payment following the receipt of a priority review voucher up to an aggregate maximum amount of $535.0 million, (iii) the achievement of certain net sales milestones up to an aggregate maximum amount of $150.0 million, and (iv) a percentage of annual net sales for FA and Angelman syndrome during specified terms, ranging from 2%-6%. The Company was required to pay $40.0 million of the development milestone payments upon the passing of the second anniversary of the closing of the Agilis Merger, regardless of whether the applicable milestones have been achieved. As of September 30, 2025, all of the milestones have either been paid or settled, with the exception of the regulatory milestones and net sales milestones related to FA and Angelman syndrome and the net sales milestones related to Upstaza/Kebilidi. In May 2023, as part of the Company’s strategic portfolio prioritization, the Company decided to discontinue its preclinical and early research programs in its gene therapy platform, which included FA and Angelman syndrome. As a result, the Company does not expect the milestones related to FA and Angelman syndrome to be achieved. In addition, the Company does not expect to pay the 2%–6% royalties on annual net sales related to FA and Angelman syndrome. As of September 30, 2025, the remaining potential sales milestones related to Upstaza/Kebilidi is $50.0 million, however the Company has determined that the probability of triggering these milestones is remote. On October 25, 2019, the Company completed the acquisition of substantially all of the assets of BioElectron Technology Corporation (“BioElectron”), a Delaware corporation, including certain compounds that the Company has begun to develop as part of its inflammation and ferroptosis platform, pursuant to an asset purchase agreement by and between the Company and BioElectron, dated October 1, 2019 (the “BioElectron Asset Purchase Agreement”). BioElectron was a private company with a pipeline focused on inflammatory CNS disorders. The lead program, vatiquinone, is in late stage development for FA with substantial unmet need and significant commercial opportunity that are complementary to PTC’s existing pipeline. Subject to the terms and conditions of the BioElectron Asset Purchase Agreement, BioElectron may become entitled to receive contingent milestone payments of up to $200.0 million (in cash or in shares of the Company’s common stock, as determined by the Company) from the Company based on the achievement of certain regulatory and net sales milestones. Subject to the terms and conditions of the BioElectron Asset Purchase Agreement, BioElectron may also become entitled to receive contingent payments based on a percentage of net sales of certain products. Subject to the terms and conditions of the Agreement and Plan of Merger, dated as of May 5, 2020 (the “Censa Merger Agreement”) by and among the Company, Censa Pharmaceuticals, Inc. (“Censa”), Hydro Merger Sub, Inc., the Company’s 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 (such merger pursuant thereto, the “Censa Merger”), former Censa securityholders may become entitled to receive contingent payments from the Company 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) $109.0 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, (iv) a percentage of annual net sales during specified terms, ranging from single to low double digits of the applicable net sales threshold amount, and (v) any sublicense fees paid to the Company in consideration of any sublicense of Censa’s intellectual property to commercialize sepiapterin, on a country-by-country basis, which contingent payment shall equal to a mid-double digit percentage of any such sublicense fees. On August 5, 2025, the Company, certain former securityholders of Censa, and, for the limited purposes set forth in the agreement, Shareholder Representative Services LLC, entered into a Rights Satisfaction Agreement (the “Rights Satisfaction Agreement”) pursuant to which such former securityholders of Censa (the “Participating Rightsholders”) agreed to the cancellation and forfeiture of their rights to receive certain contingent payments from the Company based on worldwide annual net sales by the Company of products containing sepiapterin (“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 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 $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 (collectively, the “Net Sales Payments”). In consideration of the foregoing, the Company agreed to pay to the Participating Rightsholders an aggregate amount in cash up to $250.0 million (the “Upfront Consideration”) upon the consummation of the transactions contemplated by the Rights Satisfaction Agreement 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 consummation of the transactions contemplated by the Rights Satisfaction Agreement, 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, the Company paid an aggregate amount of Upfront Consideration in cash of $225.1 million. Additionally, the Company is 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 consummation of the transactions contemplated by the Rights Satisfaction Agreement, any additional former securityholder of Censa executes and delivers a joinder to the Rights Satisfaction Agreement and becomes a party thereto, the Company 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. The Rights Satisfaction Agreement has no effect on the Censa Merger Agreement other than to provide for the cancellation and forfeiture of the Participating Rightsholders’ rights to receive the Net Sales Payments described above. As a result, all other rights and obligations under the Censa Merger Agreement remain in effect pursuant to their terms, including, without limitation, the Company’s obligation to pay certain contingent payments upon the achievement of certain development and Net Sales of Product milestones. In July 2025, Sephience™ (sepiapterin) 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 to the former Censa securityholders, which was recorded in accounts payable and accrued expenses on the Company’s consolidated balance sheet as of September 30, 2025. As of September 30, 2025, $120.0 million of the $217.5 million in development and regulatory milestones have been paid to the former Censa securityholders. The Company also has the Tegsedi-Waylivra Agreement for the commercialization of Tegsedi and Waylivra, and products containing those compounds in countries in Latin America and the Caribbean. Akcea is entitled to receive royalty payments subject to certain terms set forth in the Tegsedi-Waylivra Agreement. The Company has 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. Additionally, the Company has royalty payments associated with Translarna, Emflaza, Sephience, and Upstaza/Kebilidi net product revenue, payable quarterly or annually in accordance with the terms of the related agreements. From time to time in the ordinary course of its business, the Company is subject to claims, legal proceedings and disputes. The Company is not currently aware of any material legal proceedings against it.

Commitments and contingencies

9 Months Ended

Sep. 30, 2025

Commitments and Contingencies Disclosure [Abstract]

10. Commitments and contingencies

Under various agreements, the Company will be required to pay royalties and milestone payments upon the successful development and commercialization of products.

Pursuant to the Agreement and Plan of Merger (the “Agilis Merger Agreement”), dated as of July 19, 2018 by and among the Company, Agilis Biotherapeutics, Inc. (“Agilis”) and Agility Merger Sub, Inc. (such merger pursuant thereto, the “Agilis Merger”), Agilis equityholders were previously entitled to receive contingent consideration payments from the Company based on (i) the achievement of certain development milestones up to an aggregate maximum amount of $60.0 million, (ii) the achievement of certain regulatory approval milestones together with a milestone payment following the receipt of a priority review voucher up to an aggregate maximum amount of $535.0 million, (iii) the achievement of certain net sales milestones up to an aggregate maximum amount of $150.0 million, and (iv) a percentage of annual net sales for FA and Angelman syndrome during specified terms, ranging from 2%-6%. The Company was required to pay $40.0 million of the development milestone payments upon the passing of the second anniversary of the closing of the Agilis Merger, regardless of whether the applicable milestones have been achieved.

As of September 30, 2025, all of the milestones have either been paid or settled, with the exception of the regulatory milestones and net sales milestones related to FA and Angelman syndrome and the net sales milestones related to Upstaza/Kebilidi. In May 2023, as part of the Company’s strategic portfolio prioritization, the Company decided to discontinue its preclinical and early research programs in its gene therapy platform, which included FA and Angelman syndrome. As a result, the Company does not expect the milestones related to FA and Angelman syndrome to be achieved. In addition, the Company does not expect to pay the 2%–6% royalties on annual net sales related to FA and Angelman syndrome. As of September 30, 2025, the remaining potential sales milestones related to Upstaza/Kebilidi is $50.0 million, however the Company has determined that the probability of triggering these milestones is remote.

On October 25, 2019, the Company completed the acquisition of substantially all of the assets of BioElectron Technology Corporation (“BioElectron”), a Delaware corporation, including certain compounds that the Company has begun to develop as part of its inflammation and ferroptosis platform, pursuant to an asset purchase agreement by and between the Company and BioElectron, dated October 1, 2019 (the “BioElectron Asset Purchase Agreement”). BioElectron was a private company with a pipeline focused on inflammatory CNS disorders. The lead program, vatiquinone, is in late stage development for FA with substantial unmet need and significant commercial opportunity that are complementary to PTC’s existing pipeline.

Subject to the terms and conditions of the BioElectron Asset Purchase Agreement, BioElectron may become entitled to receive contingent milestone payments of up to $200.0 million (in cash or in shares of the Company’s common stock, as determined by the Company) from the Company based on the achievement of certain regulatory and net sales milestones. Subject to the terms and conditions of the BioElectron Asset Purchase Agreement, BioElectron may also become entitled to receive contingent payments based on a percentage of net sales of certain products.

Subject to the terms and conditions of the Agreement and Plan of Merger, dated as of May 5, 2020 (the “Censa Merger Agreement”) by and among the Company, Censa Pharmaceuticals, Inc. (“Censa”), Hydro Merger Sub, Inc., the Company’s 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 (such merger pursuant thereto, the “Censa Merger”), former Censa securityholders may become entitled to receive contingent payments from the Company 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) $109.0 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, (iv) a percentage of annual net sales during specified terms, ranging from single to low double digits of the applicable net sales threshold amount, and (v) any sublicense fees paid to the Company in consideration of any sublicense of Censa’s intellectual property to commercialize sepiapterin, on a country-by-country basis, which contingent payment shall equal to a mid-double digit percentage of any such sublicense fees. On August 5, 2025, the Company, certain former securityholders of Censa, and, for the limited purposes set forth in the agreement, Shareholder Representative Services LLC, entered into a Rights Satisfaction Agreement (the “Rights Satisfaction Agreement”) pursuant to which such former securityholders of Censa (the “Participating Rightsholders”) agreed to the cancellation and forfeiture of their rights to receive certain contingent payments from the Company based on worldwide annual net sales by the Company of products containing sepiapterin (“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 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 $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 (collectively, the “Net Sales Payments”).

In consideration of the foregoing, the Company agreed to pay to the Participating Rightsholders an aggregate amount in cash up to $250.0 million (the “Upfront Consideration”) upon the consummation of the transactions contemplated by the Rights Satisfaction Agreement 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 consummation of the transactions contemplated by the Rights Satisfaction Agreement, 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, the Company paid an aggregate amount of Upfront Consideration in cash of $225.1 million. Additionally, the Company is 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 consummation of the transactions contemplated by the Rights Satisfaction Agreement, any additional former securityholder of Censa executes and delivers a joinder to the Rights Satisfaction Agreement and becomes a party thereto, the Company 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.

The Rights Satisfaction Agreement has no effect on the Censa Merger Agreement other than to provide for the cancellation and forfeiture of the Participating Rightsholders’ rights to receive the Net Sales Payments described above. As a result, all other rights and obligations under the Censa Merger Agreement remain in effect pursuant to their terms, including, without limitation, the Company’s obligation to pay certain contingent payments upon the achievement of certain development and Net Sales of Product milestones.

In July 2025, Sephience™ (sepiapterin) 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 to the former Censa

securityholders, which was recorded in accounts payable and accrued expenses on the Company’s consolidated balance sheet as of September 30, 2025. As of September 30, 2025, $120.0 million of the $217.5 million in development and regulatory milestones have been paid to the former Censa securityholders.

The Company also has the Tegsedi-Waylivra Agreement for the commercialization of Tegsedi and Waylivra, and products containing those compounds in countries in Latin America and the Caribbean. Akcea is entitled to receive royalty payments subject to certain terms set forth in the Tegsedi-Waylivra Agreement.

The Company has 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. Additionally, the Company has royalty payments associated with Translarna, Emflaza, Sephience, and Upstaza/Kebilidi net product revenue, payable quarterly or annually in accordance with the terms of the related agreements.

From time to time in the ordinary course of its business, the Company is subject to claims, legal proceedings and disputes. The Company is not currently aware of any material legal proceedings against it.