Alnylam Notified of Defense Appropriation Funding for Ongoing Development of RNAi Therapeutics.

- Represents Congressional Support of RNAi Technology for Alnylam Biodefense(TM) Applications -

CAMBRIDGE, Mass. -- Alnylam Pharmaceuticals, Inc. (Nasdaq: ALNY), a leading RNAi therapeutics company, announced today that the Department of Defense Appropriations Act of 2007, passed by Congress last week, includes $1.1 million of funding dedicated to Alnylam's ongoing development of RNAi therapeutics. Congressional support for this effort builds upon existing public sector-private sector partnerships that the company has formed to develop RNAi therapeutics for public health. This appropriation, combined with earlier funding from the government, supports the goal of Alnylam Biodefense to build a robust platform for developing RNAi therapeutics to combat natural or man-made biological threats that pose a potential risk to public health and national security.

"We are pleased to receive this support from the U.S. Congress to develop a broad-spectrum RNAi therapeutics platform," said Barry Greene, Chief Operating Officer of Alnylam. "We believe this additional funding recognizes the potential of RNAi therapeutics as a broad platform technology that could enable the rapid and reproducible generation of pharmacological countermeasures against bioterrorism threats. With this funding and additional funding from the National Institutes of Health for the development of an RNAi therapeutic targeting the Ebola virus, we are advancing our Alnylam Biodefense efforts to meet bio-preparedness needs for U.S. military personnel and the nation. In addition, we intend to use this appropriation funding to strengthen our overall platform capabilities and its applications for discovery of RNAi therapeutics for traditional clinical indications."

About RNA Interference (RNAi)

RNA interference, or RNAi, is a naturally occurring mechanism within cells for selectively silencing and regulating specific genes. Since many diseases are caused by the inappropriate activity of specific genes, the ability to silence genes selectively through RNAi could provide a new way to treat a wide range of human diseases. RNAi is induced by small, double-stranded RNA molecules. One method to activate RNAi is with chemically synthesized small interfering RNAs, or siRNAs, which are double-stranded RNAs that are targeted to a specific disease-associated gene. The siRNA molecules are used by the natural RNAi machinery in cells to cause highly targeted gene silencing.

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, which is the leading cause of hospitalization in infants in the U.S. 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. Alnylam is honored to be the "emerging/mid-cap" company recipient of the 2006 James D. Watson Helix Award, the biotechnology industry's award for outstanding achievement. For more information, visit www.alnylam.com.

Alnylam Forward-Looking Statements

Various statements in this release concerning our future expectations, plans, and prospects, including our plans with respect to building a platform to discover and develop RNAi therapeutics to combat biological threats, 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: our approach to discover and develop novel drugs, which is unproven and may never lead to marketable products; obtaining, maintaining and protecting intellectual property utilized by our products; our ability to enforce our patents against infringers and to defend our patent portfolio against challenges from third parties; our ability to obtain additional funding to support our business activities; our dependence on third parties for development, manufacture, marketing, sales, and distribution of products; the successful development of our product candidates, all of which are in early stages of development; obtaining regulatory approval for products; competition from others using technology similar to ours and others developing products for similar uses; our dependence on collaborators; and our short operating history; as well as those risks more fully discussed in the "Risk Factors" section of our most recent report on Form 10-Q on file with the Securities and Exchange Commission. In addition, any forward-looking statements represent our views only as of today and should not be relied upon as representing our views as of any subsequent date. Alnylam does not assume any obligation to update any forward-looking statements.