X0306 4 2018-08-10 0 0001178670 ALNYLAM PHARMACEUTICALS, INC. ALNY 0001180432 MARAGANORE JOHN 300 THIRD STREET THIRD FLOOR CAMBRIDGE MA 02142 1 1 0 0 Chief Executive Officer Performance Based Stock Option 2013 (right to buy) 63 2018-08-10 4 A 0 25000 0 A 2018-08-10 2023-12-18 Common Stock 15000 75000 D Performance Based Stock Option 2014 (right to buy) 96.45 2018-08-10 4 A 0 25000 0 A 2018-08-10 2024-12-17 Common Stock 25000 75000 D On December 18, 2013, the reporting person was granted a performance based stock option to purchase shares of ALNY Common Stock. One-third of the shares subject to the option will vest upon the achievement of each of three specific clinical development and regulatory events, as approved by our compensation committee. Effective August 10, 2018, the compensation committee of the Company determined the final performance criteria had been met and the option will vest as to the final third of the award. On December 17, 2014, the reporting person was granted a performance based stock option to purchase shares of ALNY Common Stock. One-third of the shares subject to the option will vest upon the achievement of each of three specific clinical development and regulatory events, as approved by our compensation committee. Effective August 10, 2018, the compensation committee of the Company determined the final performance criteria had been met and the option vested as to the final third of the award. /s/ Michael P. Mason, Attorney-in-Fact for John M. Maraganore 2018-08-14