January 31, 2006 Morgan Stanley & Co. Incorporated Banc of America Securities LLC Piper Jaffray & Co. SG Cowen & Co., LLC Rodman & Renshaw, LLC c/o Morgan Stanley & Co. Incorporated 1585 Broadway New York, New York 10036 Ladies and Gentlemen: Alnylam...Underwriting Agreement • February 1st, 2006 • Alnylam Pharmaceuticals, Inc. • Pharmaceutical preparations • New York
