Alkermes plc

During the three months ended September 30, 2024, the following officers (as defined in Rule 16a-1(f) under the Exchange Act) of the Company adopted contracts, instructions or written plans for the purchase or sale of the Company’s securities that were intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act (each, a “Rule 10b5-1 plan”): on August 23, 2024, Christian Todd Nichols, our Senior Vice President Chief Commercial Officer, adopted a Rule 10b5-1 plan providing for the sale of up to 5,208 ordinary shares of the Company; this plan is scheduled to expire on December 31, 2024. On September 11, 2024, Samuel Parisi, our VP, Finance and Interim Chief Accounting Officer, adopted a Rule 10b5-1 plan providing for the sale of up to 10,177 ordinary shares of the Company (including shares that may be obtained from the vesting of restricted stock unit awards); this plan is scheduled to expire on February 20, 2026. During the three months ended September 30, 2024, no other officers or directors of the Company adopted, modified orterminated a Rule 10b5-1 plan or a trading plan not intended to satisfy the affirmative defense conditions of Rule 10b5-1(c) under the Exchange Act.