Item 7.01 Regulation FD Disclosure. On April 28, 2026, PTC Therapeutics, Inc. (the “ Company”) reported positive topline results from the 24-month interim analysis of the PIVOT-HD long-term extension study of votoplam. As previously announced, the Company will also provide a virtual presentation on the results on April 28, 2026 at 4:30 p. m. Eastern time. The presentation will be webcast live on the Events and Presentations page under the Investors section of the Company’s website. The full text of the press release issued in connection with the announcement and the slide presentation are furnished as Exhibits 99.1 and 99.2 to this Current Report on Form 8-K (this “ Report”), and are incorporated by reference into this Item 7.01. The information in this Item 7.01 (including Exhibits 99.1 and 99.2) shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “ Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as expressly set forth by specific reference in such a filing. All website addresses given in this Report or incorporated herein by reference are for information only and are not intended to be an active link or to incorporate any website information into this Report.

Item 9.01. Financial Statements and Exhibits. (d) Exhibits Exhibit No. Description 99.1 Press Release, dated April 28, 2026 issued by PTC Therapeutics, Inc. ────────────────────────────────────────────────────────────────────────────────────────────────── 99.2 Corporate Presentation – PIVOT-HD 24-month interim analysis 104 The cover page from this Current Report on Form 8-K, formatted in Inline XBRL SIGNATURE Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this Report to be signed on its behalf by the undersigned hereunto duly authorized. PTC Therapeutics, Inc. Date: April 28, 2026 By: /s/ Pierre Gravier Name: Pierre Gravier Title: Chief Financial Officer