Alnylam to Webcast Presentation at Piper Jaffray Second Annual London Health Care Conference.

CAMBRIDGE, Mass. -- Alnylam Pharmaceuticals, Inc. (Nasdaq: ALNY), a leading RNAi therapeutics company, today announced that management will present a company overview at the Piper Jaffray Second Annual London Health Care Conference on Thursday, June 21, 2007, at 12:20 p.m. BST (7:20 a.m. ET) at the Great Eastern Hotel in London.

A live audio webcast of the presentation will be available on the "Investors" section of the company's website, www.alnylam.com. A replay of the presentation will be available on the Alnylam website within 48 hours after the event and will be archived for 14 days.

About Alnylam

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 building a pipeline of RNAi therapeutics; its lead program is in Phase I human clinical trials for the treatment of respiratory syncytial virus (RSV) infection. RSV infects nearly every child at least once by the age of two and accounts for more than 125,000 hospitalizations annually in the U.S. pediatric population. RSV infection also poses a great risk to the elderly and other adults with compromised immune systems. 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 Merck, Medtronic, Novartis, and Biogen Idec. The company, founded in 2002, maintains global headquarters in Cambridge, Massachusetts, and has an additional operating unit in Kulmbach, Germany. For more information, visit www.alnylam.com.