Material Agreement (Form 8-K)

Item 1.01. Entry into a Material Definitive Agreement.

On September 9, 2025, Alkermes Pharma Ireland Limited ("APIL"), a wholly-owned indirect subsidiary of Alkermes plc (the "Company"), entered into an authorized generic product supply agreement (the "AG Agreement") with Amneal Pharmaceuticals LLC ("Amneal" and each of APIL and Amneal, a "Party", and together, the "Parties"), pursuant to which APIL granted Amneal certain rights to distribute and sell in the United States an authorized generic version of VIVITROL®(naltrexone for extended-release injectable suspension), 380mg per vial, for a one-year term beginning on the date of a Third Party ANDA Product Launch (such authorized generic product, the "Amneal AG Product"), provided, however, that if a Third Party ANDA Product Launch does not occur within ninety (90) days after January 15, 2027 (or an earlier launch date under certain circumstances), Amneal shall no longer have the right to distribute and sell the Amneal AG Product. The Parties entered into the AG Agreement pursuant to the previously disclosed settlement and license agreement by and between the Parties.

Under the AG Agreement, APIL agreed to supply to Amneal, upon Amneal's request, a limited quantity of the Amneal AG Product, which amount would not exceed approximately 15% of 2024 VIVITROL unit sales. APIL will be entitled to payment for supply of the Amneal AG Product at a premium to APIL's fully burdened manufacturing cost. APIL and Amneal will share any Net Profits from the sales of the Amneal AG Product, as specified in the Agreement.

Among other customary termination rights, the AG Agreement may be terminated upon written notice in the event of an uncured material breach or upon the occurrence of certain specified events, including Amneal's launch of a generic version of VIVITROL (other than the Amneal AG Product). Unless earlier terminated in accordance with its terms, the term of the AG Agreement shall extend until Amneal's last profit share payment is made to APIL.

The AG Agreement also contains customary representations and warranties, indemnification, confidentiality, dispute resolution, termination and other customary provisions for authorized generic supply agreements of this nature and is subject to modification under certain customary circumstances.

The foregoing description of the AG Agreement does not purport to be complete, provides only a summary of the material terms of the AG Agreement, and is qualified in its entirety by reference to the AG Agreement, a copy of which will be filed as an exhibit to the Company's Quarterly Report on Form 10-Q for the quarter ending September 30, 2025. Capitalized terms used and not otherwise defined herein shall have the meanings ascribed to them in the AG Agreement.

Item 8.01 Other Events.

On August 15, 2025, August 27, 2025 and September 5, 2025, APIL and Alkermes, Inc., indirect wholly-owned subsidiaries of the Company, filed a patent infringement lawsuit in the United States District Court for the District of New Jersey against each of Teva, Apotex, and MSN (each as defined herein), respectively, and on August 28, 2025, APIL and Alkermes, Inc. filed a patent infringement lawsuit in the United States District Court for the District of Delaware against Apotex. As used herein, Teva refers to Teva Pharmaceuticals, Inc. ("Teva Pharms") and Teva Pharmaceutical Industries, Ltd., Apotex refers to Apotex Inc. and Apotex Corp., and MSN refers to MSN Laboratories Private Limited ("MSN Labs"), MSN Pharmaceuticals, Inc. and Novadoz Pharmaceuticals LLC.

These lawsuits were filed following receipt of a "paragraph IV certification" notice from each of Teva Pharms, Apotex and MSN Labs regarding their respective filings of an abbreviated new drug application (each, an "ANDA") with the U.S. Food and Drug Administration (the "FDA") seeking approval to engage in the commercial manufacture, use or sale of a generic version of LYBALVI® (olanzapine and samidorphan tablets, 5mg/10mg, 10mg/10mg, 15mg/10mg and 20mg/10mg) in the United States prior to the expiration of certain of the Company's U.S. patents. The notices alleged that certain of the Company's patents related to LYBALVI, with expiration dates between 2032 and 2041, are invalid, unenforceable and/or will not be infringed by the commercial manufacture, use or sale of the proposed generic products. Alkermes intends to vigorously defend its intellectual property. The filing of each lawsuit within 45 days of receipt of each of the respective notices triggered stays of FDA approval of each of the respective ANDAs for up to 30 months in accordance with the U.S. Drug Price Competition and Patent Term Restoration Act of 1984 (the Hatch-Waxman Act). On August 20, 2025, APIL and Alkermes, Inc. amended the complaint in the lawsuit against Teva to include an additional patent.

2

SIGNATURE