X0306 4 2015-05-01 0 0001178670 ALNYLAM PHARMACEUTICALS, INC. ALNY 0001620743 KEATING LAURIE C/O ALNYLAM PHARMACEUTICALS, INC. 300 THIRD STREET CAMBRIDGE MA 02142 0 1 0 0 SVP, GC and Secretary Common Stock 28 I By Managed Account Stock Option (Right to Buy) 96.45 2015-05-01 4 A 0 5959 0 A 2024-12-17 Common Stock 5959 5959 D The reporting person owns 28 shares of ALNY common stock under the ALNY 401(k) plan as a result of the ALNY 401(k) matching contribution program. On December 17, 2014, the Compensation Committee of the Company approved the grant of stock options, at an exercise price of $96.45 per share, to members of its management team, including the Reporting Person. These stock option grants were approved subject to and contingent upon approval by the stockholders of the Company at its 2015 annual meeting of the Amended and Restated 2009 Stock Incentive Plan, to, among other things, increase the shares authorized for issuance thereunder. On May 1, 2015, the stockholders of the Company approved the Amended and Restated 2009 Stock Incentive Plan. The stock option vests as to 25% of the shares on the first anniversary of the date of the stock option grant and as to an additional 6.25% of the shares each successive three month period thereafter. /s/ Michael P. Mason, Attorney-in-Fact for: Laurie B. Keating 2015-05-05