Alkermes plc

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers. On September 14, 2026, the board of directors (the “Board”) of Alkermes plc (the “Company”) increased the size of the Board from ten (10) to eleven (11) directors and appointed Anne C. Whitaker to the Board, effective immediately, with an initial term expiring at the Company’s 2027 annual general meeting of shareholders. As of the date of this Current Report on Form 8-K, Ms. Whitaker has not been appointed to any committee of the Board. For her service on the Board, Ms. Whitaker will be entitled to receive an annual cash retainer and annual equity grant, both of which will be on the terms, and in the amounts, as determined in accordance with the processes described in the “Director Compensation” section of the Company’s definitive proxy statement filed with the Securities and Exchange Commission (the “SEC”) on April 6, 2026. In addition, in connection with her appointment to the Board, Ms. Whitaker will be granted an initial new director equity award with an aggregate target value of $600,000, consisting of 50% stock options and 50% restricted stock unit awards, which will vest and, as applicable, become exercisable in three equal annual installments commencing on the first anniversary of the grant date, subject to Ms. Whitaker’s continuous service. The new director equity award is expected to be granted to Ms. Whitaker in October 2026, on the Company’s monthly new hire employee grant date. The exercise price per share of the stock options will be equal to the closing price of the Company’s ordinary shares on the date of grant, as reported on the Nasdaq Global Select Market. In addition, the Company has entered into a deed of indemnification with Ms. Whitaker in substantially the form filed as Exhibit 10.1 to the Company’s Quarterly Report on Form 10-Q filed with the SEC on April 29, 2020, and Alkermes, Inc., a wholly-owned indirect subsidiary of the Company, has entered into an indemnification agreement with Ms. Whitaker in substantially the form filed as Exhibit 10.2 to the Company’s Quarterly Report on Form 10-Q filed with the SEC on April 29, 2020. Ms. Whitaker is not, nor has been since January 1, 2025, a participant in any transaction involving the Company, or a participant in any proposed transaction with the Company, in each case, required to be disclosed pursuant to Item 404(a) of Regulation S-K.

Item 7.01 Regulation FD Disclosure. On September 16, 2026, the Company issued a press release announcing Ms. Whitaker’s appointment to the Board, a copy of which is furnished herewith as Exhibit 99.1 and is incorporated herein by reference. This Item 7.01 and 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, nor shall such information 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.