X0303 4 2011-06-01 0000874663 ALKERMES INC ALKS 0001376548 Ehrich Elliot 852 WINTER ST. WALTHAM MA 02451 1 SVP, R&D & Chief Medical Ofcr Common Stock 2011-06-01 4 F 0 477 17.87 D 19602 D Common Stock 2011-06-02 4 S 0 1023 17.80 D 18579 D This sale was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person. /s/ Jennifer Baptiste, attorney-in-fact for Elliot Ehrich 2011-06-02