Alnylam to Webcast Conference Call Discussing Fourth Quarter and 2009 Financial Results

Alnylam Pharmaceuticals, Inc. (Nasdaq: ALNY), a leading RNAi therapeutics company, today announced that it will report financial results for the fourth quarter and year ending December 31, 2009 on Thursday, February 25, 2010, after the U.S. financial markets close.

Management will provide an update on the company, discuss fourth quarter and year-end results, and discuss expectations for the future via conference call on February 25, 2010 at 4:30 p.m. ET. To access the call, please dial 800-299-0148 (domestic) or 617-801-9711 (international) five minutes prior to the start time and provide the passcode 31780756. A replay of the call will be available beginning at 7:30 p.m. ET on February 25, 2010. To access the replay, please dial 888-286-8010 (domestic) or 617-801-6888 (international), and provide the passcode 36368070.

A live audio webcast of the call will also be available on the "Investors” section of the company’s website, www.alnylam.com. An archived webcast will be available on the Alnylam website approximately two hours after the event.

About Alnylam Pharmaceuticals

Alnylam is a biopharmaceutical company developing novel therapeutics based on RNA interference, or RNAi. The company is applying its therapeutic expertise in RNAi to address significant medical needs, many of which cannot effectively be addressed with small molecules or antibodies, the current major classes of drugs. Alnylam is leading the translation of RNAi as a new class of innovative medicines with peer-reviewed research efforts published in the world’s top scientific journals including Nature, Nature Medicine, and Cell. The company is leveraging these capabilities to build a broad pipeline of RNAi therapeutics; its most advanced program is in Phase II human clinical trials for the treatment of respiratory syncytial virus (RSV) infection and is partnered with Cubist and Kyowa Hakko Kirin. In addition, the company is developing RNAi therapeutics for the treatment of a wide range of disease areas, including liver cancers, TTR-mediated amyloidosis, hypercholesterolemia, and Huntington’s disease. The company’s leadership position in fundamental patents, technology, and know-how relating to RNAi has enabled it to form major alliances with leading companies including Medtronic, Novartis, Biogen Idec, Roche, Takeda, Kyowa Hakko Kirin, and Cubist. Alnylam and Isis are joint owners of Regulus Therapeutics Inc., a company focused on the discovery, development, and commercialization of microRNA-based therapeutics. Founded in 2002, Alnylam maintains headquarters in Cambridge, Massachusetts. For more information, please visit www.alnylam.com.