X0609 4 2026-08-17 0001520262 Alkermes plc. ALKS 0001813312 Nichols Christian Todd false 900 WINTER STREET WALTHAM MA 02451 1 SVP, Chief Commercial Officer 1 Ordinary Shares 2026-08-17 4 S 0 6912 49.1851 D 102857 D Ordinary Shares 2026-08-17 4 S 0 664 49.6526 D 102193 D This sale was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on 5/15/2026. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $48.6092 to $49.49. Full information regarding the number of shares sold at each separate price can be provided to the issuer, any security holder of the issuer or the SEC staff upon request. The price reported in Column 4 is a weighted average price. The shares were sold in multiple transactions at prices ranging from $49.61 to $49.79. Full information regarding the number of shares sold at each separate price can be provided to the issuer, any security holder of the issuer or the SEC staff upon request. /s/ Shantale Greenson, attorney-in-fact for Christian Todd Nichols 2026-08-17