Alnylam's Vice President, Drug Discovery and Development Honored with American Chemical Society Award.

Alnylam Presents Advancements with Chemical Modifications for RNAi Therapeutics at American Chemical Society 234(th) National Meeting

CAMBRIDGE, Mass. -- Alnylam Pharmaceuticals, Inc. (Nasdaq: ALNY), a leading RNAi therapeutics company, today announced that Dr. Muthiah Manoharan, Vice President, Drug Discovery and Development, has been honored with the Melville L. Wolfrom Award of the Division of Carbohydrate Chemistry of the American Chemical Society.

"We are extremely proud of Mano and this recognition by the American Chemical Society for his significant contributions to the field of oligonucleotide-based therapies," said John Maraganore, Ph.D., President and Chief Executive Officer of Alnylam. "Mano and his chemistry team have been instrumental in our efforts to translate the breakthrough discovery of RNAi into a whole new class of human therapeutics. Indeed, innovations in biology require solutions from great chemists, and we're honored to have such a chemist in a leadership role at Alnylam."

The Wolfrom Award is intended to recognize those individuals who have provided outstanding service to the Division of Carbohydrate Chemistry and/or to the field of Carbohydrate Chemistry. Dr. Manoharan has invented and widely published numerous nucleic acid related novel carbohydrate modifications which have significantly improved the drug like properties of small interfering RNAs (siRNAs), the molecules that mediate RNAi, and other oligonucleotide drugs. The award will be presented to Dr. Manoharan at the American Chemical Society 234th National Meeting being held in Boston, August 19-23, 2007.

Additionally, in a symposium titled "RNA Interference Based Therapeutics" Alnylam scientists and leaders from academia and industry will be presenting a number of presentations discussing further advancements in the therapeutic understanding of chemical modifications to siRNAs. The presentations are as follows:

Session: RNA Interference Based Therapeutics (BCEC -- 208, Oral)
Date and Time: Tuesday, August 21, 8:30 - 11:50 a.m.
"Discovery and development of RNAi-based therapeutics: An overview"
(CARB 37)
"siRNAs with a Universal Base" (CARB 42)

Session: RNA Interference Based Therapeutics (BCEC -- 208, Oral)
Date and Time: Tuesday, August 21, 1:25 - 4:45 p.m.
"Delivering RNAi Therapeutics" (CARB 46)
"Lipophilic conjugates for the in vivo delivery of siRNA" (CARB 51)
"Metal-ion chelated siRNA used to study distribution and uptake of
siRNA" (CARB 52)

General Poster Session
Date and Time: Tuesday, August 21, 6:00 - 8:00 p.m., (BCEC -- Exhibit
Hall - B2)
"Effect of ligand tethered 2,4-difluorotoluyl ribonucleosides on RNA
interference" (CARB 56)
"Polyethylene glycol (PEG) conjugates for in vivo delivery of siRNA"
(CARB 54)

Session: Protein-Nucleic Acid Interactions
Date and Time: Monday, August 20, 10:45 - 11:15 a.m. (BCEC-156B, Oral)
"Probing the structure and activity of DNA-/RNA-processing enzymes
with the 2,4-difluorotoluyl/ribo-2,4-difluorotoluyl (dF/rF)
nucleoside, an apolar thymidine/uridine analog" (COMP144)

About RNA Interference (RNAi)

RNAi is a revolution in biology, representing a breakthrough in understanding how genes are turned on and off in cells, and a completely new approach to drug discovery and development. Its discovery has been heralded as "a major scientific breakthrough that happens once every decade or so," and represents one of the most promising and rapidly advancing frontiers in biology and drug discovery today which was awarded the 2006 Nobel Prize for Physiology or Medicine. RNAi is a natural process of gene silencing that occurs in organisms ranging from plants to mammals. By harnessing the natural biological process of RNAi occurring in our cells, the creation of a major new class of medicines, known as RNAi therapeutics, is on the horizon. RNAi therapeutics target the cause of diseases by potently silencing specific messenger RNAs (mRNAs), thereby preventing disease-causing proteins from being made. RNAi therapeutics have the potential to treat disease and help patients in a fundamentally new way.

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. In addition, the company is developing RNAi therapeutics for the treatment of influenza, hypercholesterolemia, and liver cancers, amongst other diseases. 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, Biogen Idec, and Roche. The company, founded in 2002, maintains headquarters in Cambridge, Massachusetts. For more information, visit www.alnylam.com.

Alnylam Forward-Looking Statements

Various statements in this release concerning Alnylam's future expectations, plans and prospects, constitute forward-looking statements for the purposes of the safe harbor provisions under The Private Securities Litigation Reform Act of 1995. Actual results may differ materially from those indicated by these forward-looking statements as a result of various important factors, including risks related to: Alnylam's approach to discover and develop novel drugs, which is unproven and may never lead to marketable products; Alnylam's ability to attract and retain highly qualified employees; obtaining, maintaining and protecting intellectual property utilized by Alnylam's products; Alnylam's ability to enforce its patents against infringers and to defend its patent portfolio against challenges from third parties; Alnylam's ability to obtain additional funding to support its business activities; Alnylam's dependence on third parties for development, manufacture, marketing, sales and distribution of products; the successful development of Alnylam's product candidates, all of which are in early stages of development; obtaining regulatory approval for products; competition from others using technology similar to Alnylam's and others developing products for similar uses; Alnylam's dependence on collaborators; and Alnylam's short operating history; as well as those risks more fully discussed in the "Risk Factors" section of its most recent quarterly report on Form 10-Q on file with the Securities and Exchange Commission. In addition, any forward-looking statements represent Alnylam's views only as of today and should not be relied upon as representing its views as of any subsequent date. Alnylam does not assume any obligation to update any forward-looking statements.