X0508 4 2024-02-18 0001520262 Alkermes plc. ALKS 0001813312 Nichols Christian Todd 900 WINTER ST. WALTHAM MA 02451 1 SVP, Chief Commercial Officer 0 Ordinary Shares 2024-02-18 4 M 0 6355 A 68161 D Ordinary Shares 2024-02-18 4 F 0 1869 32.18 D 66292 D Ordinary Shares 2024-02-20 4 M 0 3901 A 70193 D Ordinary Shares 2024-02-20 4 F 0 1379 30.39 D 68814 D Employee Stock Option (Right to Buy) 22.94 2023-11-17 5 J 0 E 999 22.94 A 2029-06-05 Ordinary Shares 999 50999 D Employee Stock Option (Right to Buy) 20.03 2023-11-17 5 J 0 E 885 20.03 A 2030-02-20 Ordinary Shares 885 45212 D Restricted Stock Unit Award 2023-11-17 5 J 0 E 76 A Ordinary Shares 76 3901 D Employee Stock Option (Right to Buy) 19.34 2023-11-17 5 J 0 E 2274 19.34 A 2031-02-22 Ordinary Shares 2274 116028 D Restricted Stock Unit Award 2023-11-17 5 J 0 E 278 A Ordinary Shares 278 14217 D Employee Stock Option (Right to Buy) 24.59 2023-11-17 5 J 0 E 1992 24.59 A 2032-02-18 Ordinary Shares 1992 101674 D Restricted Stock Unit Award 2023-11-17 5 J 0 E 373 A Ordinary Shares 373 19064 D Employee Stock Option (Right to Buy) 26.82 2023-11-17 5 J 0 E 2010 26.82 A 2033-02-23 Ordinary Shares 2010 102522 D Restricted Stock Unit Award 2023-11-17 5 J 0 E 502 A Ordinary Shares 502 25630 D Restricted Stock Unit Award 2024-02-18 4 M 0 6355 D Ordinary Shares 6355 12709 D Restricted Stock Unit Award 2024-02-20 4 M 0 3901 D Ordinary Shares 3901 0 D Each restricted stock unit represents a contingent right to receive one ordinary share. Represents an equity award granted prior to the separation of the issuer's oncology business into Mural Oncology plc (the "Separation"), as adjusted on November 17, 2023 in connection with the Separation (in order to preserve the value associated with the original award) based on the equity adjustment terms set forth in the Employee Matters Agreement filed by the issuer as Exhibit 10.2 to its Current Report on Form 8-K filed with the U.S. Securities and Exchange Commission on November 15, 2023. The exercise price (if any) of the adjusted award is shown in Boxes 2 and 8, the number of shares subject to the adjusted award is shown in Box 9 and the number of shares added to the award pursuant to the adjustment is shown in Box 5. These options are fully vested in accordance with their terms. Shares subject to the stock option award vest and become exercisable in four equal annual installments commencing on 2/20/2021. Shares subject to the restricted stock unit award vest in four equal annual installments, commencing on 2/20/2021. Shares underlying the stock option vest and become exercisable in four equal annual installments commencing on 2/22/2022. Shares subject to the restricted stock unit award vest in four equal annual installments, commencing on 2/22/2022. Shares underlying the stock option vest and become exercisable in four equal annual installments commencing on 2/18/2023. Shares subject to the restricted stock unit award vest in four equal annual installments, commencing on 2/18/2023. Shares underlying the stock option vest and become exercisable in four equal annual installments commencing on 2/23/2024. Shares subject to the restricted stock unit award vest in four equal annual installments, commencing on 2/23/2024. EXHIBIT LIST: Exhibit 24.1 - Power of Attorney /s/ Jeffrey Geary, attorney-in-fact for Christian Todd Nichols 2024-02-21