ALKS: Company disclosure · Other company developments

Item 7.01 Regulation FD Disclosure. On September 21, 2026, Alkermes plc (the “Company”) issued a press release regarding the positive topline results described in Item 8.01 of this Current Report on Form 8-K. A copy of the press release is furnished herewith as Exhibit 99.1 and is incorporated herein by reference. The information in this Item 7.01, and in Exhibit 99.1 furnished herewith, 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, or incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such a filing. Item 8.01 Other Events. On September 21, 2026, the Company announced positive topline results from a phase 1 proof-of-concept study evaluating ALKS 7290, the Company’s novel, investigational orexin 2 receptor (OX2R) agonist in development for the treatment of attention-deficit hyperactivity disorder (ADHD). Item 9.01 Financial Sta tements and Exhibits. (d) Exhibits EXHIBIT INDEX Exhibit No. Description 99.1 Press release issued by Alkermes plc dated September 21, 2026. 104 Cover page interactive data file (embedded within the Inline XBRL document). 2 SIGNA TURE 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. ALKERMES PLC Date: September 21, 2026 By: /s/ David J. Gaffin David J. Gaffin Secretary 3