ALKS: Company disclosure · Other company developments

Item 7.01 Regulation FD Disclosure. On May 12, 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 May 12, 2026, the Company announced positive topline results from REVITALYZ SM , a double-blind, placebo-controlled, randomized withdrawal, multicenter phase 3 study evaluating the investigational use of LUMRYZ ® (sodium oxybate) extended-release oral suspension compared to placebo in adults with idiopathic hypersomnia. Item 9.01 Financial Sta tements and Exhibits. (d) Exhibits EXHIBIT INDEX Exhibit No. Description 99.1 Press release issued by Alkermes plc dated May 12, 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: May 12, 2026 By: /s/ David J. Gaffin David J. Gaffin Secretary 3