Alnylam Pharmaceuticals, Inc. (Nasdaq: ALNY), a leading RNAi therapeutics company, and KOKEN Co., Ltd., a leading atelocollagen company, announced today that Alnylam has granted KOKEN a non-exclusive worldwide license to manufacture and provide RNAi research products and services under the Kreutzer-Limmer patent family. This patent family, owned exclusively by Alnylam, covers fundamental aspects of the structure and uses of RNAi products, including small interfering RNAs (siRNAs) and their use to mediate RNAi in mammalian cells, and of RNAi-related mechanisms.

“We are pleased to grant KOKEN a license to manufacture and provide siRNA reagents to its industry and academic customers around the world for research purposes,” said Jason Rhodes, Vice President of Business Development at Alnylam. “This new agreement continues to underscore the value of the Kreutzer-Limmer patent family as a critical component of fundamental intellectual property in the field of RNAi. With more than 15 license agreements with global research product suppliers, including five in the Asian markets alone, we believe the vast majority of industrial sales of RNAi products for research purposes are currently being made under a license from Alnylam."

“This new agreement with Alnylam enhances our ability to become a leading global supplier of innovative RNAi reagent products in Japan and worldwide,” said Yuzo Tarumi, Ph.D., President of KOKEN. “Access to the Kreutzer-Limmer patent estate enables us to augment our current RNAi products, thereby strengthening our position in the life sciences marketplace.”

Alnylam’s intellectual property estate includes certain fundamental patents and patent applications, including the Kreutzer-Limmer I and II patents, which claim the broad structural and functional properties of synthetic RNAi products.

About RNA Interference (RNAi)

1BRNAi (RNA interference) 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. Small interfering RNAs (siRNAs), the molecules that mediate RNAi and comprise Alnylam’s RNAi therapeutic platform, target the cause of diseases by potently silencing specific 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 and is partnered with Cubist and Kyowa Hakko. In addition, the company is developing RNAi therapeutics for the treatment of a wide range of disease areas, including liver cancers, hypercholesterolemia, Huntington’s disease, and TTR amyloidosis. 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, and Cubist. To reflect its outlook for key scientific, clinical, and business initiatives, Alnylam established “RNAi 2010” in January 2008 which includes the company’s plan to significantly expand the scope of delivery solutions for RNAi therapeutics, have four or more programs in clinical development, and to form four or more new major business collaborations, all by the end of 2010. Alnylam is a joint owner of Regulus Therapeutics, a joint venture focused on the discovery, development, and commercialization of microRNA therapeutics. Founded in 2002, Alnylam maintains headquarters in Cambridge, Massachusetts. For more information, please visit http://Hwww.alnylam.com.

About KOKEN

Koken is a leading company in atelocollagen and celebrated the Golden Anniversary of the founding this year. Koken’s unique technology using proteolytic enzyme yields water-soluble collagen, atelocollagen. Atelocollagen has extremely low antigenicity and is remarkably compatible with and stable to other material. Koken has also found applications of atelocollagen in various types of drug delivery systems (DDS), especially for nucleic acid. Based on this character of atelocollagen, Koken has launched in vivo siRNA transfection kit for research use “AteloGene^®” worldwide. In addition, Koken is selling high-quality siRNA for research use, “AteloSiLence^®” in Japan. Koken has headquarters in Mejiro, Tokyo. For more information, please visit http://www.kokenmpc.co.jp.

Alnylam Forward-Looking Statement

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 the company's ability to successfully research and develop products and to successfully prosecute and enforce its patents around the world, 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.