Item 7.01. Regulation FD Disclosure. PTC Therapeutics, Inc. (the “ Company”) will host a conference call on May 5, 2025 at 8:00 a. m. Eastern Time. During this conference call, the Company expects to discuss results from its Phase 2 study of PTC518 for the treatment of Huntington’s disease. Directions on how to access the conference call and a summary of the results are included in the press release furnished as Exhibit 99.1 hereto. A copy of the slide deck that will be presented during the conference call is furnished as Exhibit 99.2 hereto. The information in this Item 7.01 of this Current Report on Form 8-K (this “ Report”), 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 May 5, 2025 issued by PTC Therapeutics, Inc. ────────────────────────────────────────────────────────────────────────────────────────────────── 99.2 Corporate Presentation — PIVOT-HD Results 104 The cover page from this Current Report on Form 8-K, formatted in Inline XBRL Signature