Material Agreement (Form 8-K)

Item 1.01. Entry into a Material Definitive Agreement.

On August 25, 2026, PTC Therapeutics, Inc. (the "Company") entered into an asset purchase agreement (the "Asset Purchase Agreement") with Sangamo Therapeutics, Inc. ("Sangamo"), pursuant to which the Company agreed to acquire from Sangamo, subject to the terms and conditions set forth in the Asset Purchase Agreement, all of Sangamo's right, title and interest in and to the assets primarily related to ST-920, a one-time administered AAV gene therapy product candidate for Fabry disease, and to assume certain specified liabilities of Sangamo, for an upfront payment of $111 million, plus up to an additional $100 million in contingent milestone payments (collectively, the "Acquisition"). The contingent milestone payments consist of $80 million upon accelerated approval by the U.S. Food and Drug Administration (the "FDA") of a biologics license application ("BLA") for ST-920 for the treatment of Fabry disease based on Sangamo's Phase 1/2 STAAR study and related long-term follow-up clinical study (the "STAAR Studies") and $20 million upon full approval by the FDA of a BLA for ST-920 for the treatment of Fabry disease based on the STAAR Studies (either as part of the original BLA submission or if an accelerated approval is subsequently converted into a full approval). The Company previously announced that the Company was selected as the winning bidder to acquire ST-920 in a competitive bankruptcy auction conducted in connection with the Chapter 11 bankruptcy case of Sangamo (the "Bankruptcy Case").

The Asset Purchase Agreement contains customary representations, warranties and covenants of the parties for a transaction involving the acquisition of assets from a debtor in bankruptcy, and the completion of the Acquisition is subject to a number of customary conditions, which includes, among others, the entry of an order of the United States Bankruptcy Court for District of Delaware (the "Bankruptcy Court") authorizing and approving the Acquisition, the expiration or termination of the applicable waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, accuracy of each party's representations (subject to specified materiality qualifications) and performance in all material respects by each party of its obligations under the Asset Purchase Agreement. None of the representations or warranties contained in the Asset Purchase Agreement survive the closing of the Acquisition, nor does the Asset Purchase Agreement provide for indemnification for any breach of such representations or warranties. The Asset Purchase Agreement provides that the Company shall use commercially reasonable efforts to achieve the contingent milestone events.

The Asset Purchase Agreement contains customary termination provisions, including rights exercisable by either party, by the Company alone, by Sangamo alone, or that arise upon the occurrence of specified events, including failure to satisfy specified Bankruptcy Case process deadlines and the occurrence of certain Bankruptcy Court or Bankruptcy Case-related events adverse to the Company, including if the Bankruptcy Court denies approval of the Acquisition. The Company and Sangamo each have the right to terminate the Asset Purchase Agreement if the closing of the Acquisition has not occurred on or before October 15, 2026, subject to certain specified exceptions.

A hearing before the Bankruptcy Court to consider approval of the Asset Purchase Agreement and the Acquisition is currently scheduled for September 10, 2026.

The representations, warranties and covenants set forth in the Asset Purchase Agreement have been made only for purposes of the Asset Purchase Agreement and solely for the benefit of the parties thereto. Moreover, certain of those representations and warranties may not be accurate or complete as of any specified date, may be modified in important part by the underlying disclosure schedules which are not filed publicly, may be subject to a contractual standard of materiality different from those generally applicable to Securities and Exchange Commission filings or may have been used for purposes of allocating risk among the parties to the Asset Purchase Agreement, rather than establishing matters of fact. In addition, information regarding the subject matter of the representations, warranties and covenants made in the Asset Purchase Agreement may change after the date of the Asset Purchase Agreement and do not purport to be accurate as of the date of this Current Report on Form 8-K (this "Report"). Accordingly, investors should not rely upon the representations, warranties or covenants in the Asset Purchase Agreement or any descriptions thereof as statements of factual information or conditions of the parties thereto.

The foregoing summary of the Asset Purchase Agreement is not complete and is qualified in its entirety by reference to the full text of the Asset Purchase Agreement, a copy of which will be filed as an exhibit to the Company's Quarterly Report on Form 10-Q for the quarter ending September 30, 2026.