Alnylam to Webcast Conference Call Discussing Third Quarter 2012 Financial Results

Alnylam to Webcast Conference Call Discussing Third Quarter 2012 Financial Results

<0> Investors:Cynthia Clayton, 617-551-8207orMedia:SpectrumAmanda Sellers, 202-955-6222 x2597 </0>

Alnylam Pharmaceuticals, Inc. (Nasdaq: ALNY), a leading RNAi therapeutics company, today announced that it will report financial results for the third quarter ending September 30, 2012 on Monday, November 5, 2012, after the U.S. financial markets close.

Management will provide an update on the company, discuss third quarter results, and discuss expectations for the future via conference call on Monday, November 5, 2012 at 4:30 p.m. ET. To access the call, please dial 800-901-5248 (domestic) or 617-786-4512 (international) five minutes prior to the start time and provide the passcode 16984515. A replay of the call will be available beginning at 6:30 p.m. ET on November 5, 2012. To access the replay, please dial 888-286-8010 (domestic) or 617-801-6888 (international), and provide the passcode 79599567.

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

Alnylam is a biopharmaceutical company developing novel therapeutics based on RNA interference, or RNAi. The company is leading the translation of RNAi as a new class of innovative medicines with a core focus on RNAi therapeutics for the treatment of genetically defined diseases, including ALN-TTR for the treatment of transthyretin-mediated amyloidosis (ATTR), ALN-AT3 for the treatment of hemophilia, ALN-PCS for the treatment of severe hypercholesterolemia, ALN-HPN for the treatment of refractory anemia, and ALN-TMP for the treatment of hemoglobinopathies. As part of its “Alnylam 5x15” strategy, the company expects to have five RNAi therapeutic products for genetically defined diseases in clinical development, including programs in advanced stages, on its own or with a partner by the end of 2015. Alnylam has additional partnered programs in clinical or development stages, including ALN-RSV01 for the treatment of respiratory syncytial virus (RSV) infection, ALN-VSP for the treatment of liver cancers, and ALN-HTT for the treatment of Huntington’s disease. The company’s leadership position on RNAi therapeutics and intellectual property have enabled it to form major alliances with leading companies including Merck, Medtronic, Novartis, Biogen Idec, Roche, Takeda, Kyowa Hakko Kirin, Cubist, Ascletis, Monsanto, and Genzyme. In addition, Alnylam and Isis co-founded Regulus Therapeutics Inc., a company focused on discovery, development, and commercialization of microRNA therapeutics; Regulus has formed partnerships with GlaxoSmithKline, Sanofi, AstraZeneca and Biogen Idec. Alnylam has also formed Alnylam Biotherapeutics, a division of the company focused on the development of RNAi technologies for applications in biologics manufacturing, including recombinant proteins and monoclonal antibodies. Alnylam’s VaxiRNA™ platform applies RNAi technology to improve the manufacturing processes for vaccines; GlaxoSmithKline is a collaborator in this effort. Alnylam scientists and collaborators have published their research on RNAi therapeutics in over 100 peer-reviewed papers, including many in the world’s top scientific journals such as , , , and . Founded in 2002, Alnylam maintains headquarters in Cambridge, Massachusetts. For more information, please visit .