News Release

Acquisition Expands Alnylam Intellectual Property Estate, Includes Several Early and Broad RNAi Patent Families

CAMBRIDGE, Mass.--(BUSINESS WIRE)--Dec. 8, 2008--Alnylam Pharmaceuticals, Inc. (Nasdaq: ALNY), a leading RNAi therapeutics company, announced today that it has acquired the intellectual property (IP) assets of Nucleonics, Inc., a privately held biotechnology company. The Nucleonics IP estate includes over 100 active patent filings, including 16 that have granted worldwide and 6 that have been granted in the U.S., Europe, or Japan - the world's largest pharmaceutical markets.

The Nucleonics IP estate includes certain early patents and patent applications, notably the "Li & Kirby," "Pachuk I," and "Giordano" patent families, that cover broad structural features of RNAi therapeutics and extend the breadth of Alnylam's "fundamental" IP, which is comprised of the Crooke, Fire & Mello, Kreutzer-Limmer, Glover, Tuschl I, Tuschl II, Hannon, and Kay patent families. With this acquisition, Alnylam has extended the scope of its overall IP estate for RNAi therapeutics, which now includes over 1,800 active cases. Financial terms of the acquisition were not disclosed; however, this transaction does not change Alnylam's financial guidance of ending the year with greater than $500 million in cash.

"Nucleonics was one of the first companies in the RNAi therapeutics space focused primarily on gene therapy applications of RNAi. As they built their company, they acquired a number of early and broad patent families that are relevant for development and commercialization of all RNAi therapeutics, including synthetic small interfering RNAs, or 'siRNAs,' the molecules that mediate RNAi, which remain Alnylam's sole focus," said Barry Greene, President and Chief Operating Officer of Alnylam. "When added to our existing IP estate, which is already dominant in the field, the Nucleonics IP estate provides further strengthening of a portfolio that is buttressed across all possible dimensions. Importantly, Alnylam's IP estate is defined by a very large number of distinct patent elements that in aggregate define the overall strength of our exclusivity in the RNAi therapeutics field."

"The Nucleonics IP portfolio we acquired today adds very significantly to our current IP estate for RNAi therapeutics," said Donna Ward, Ph.D., Vice President, Intellectual Property at Alnylam. "In particular, we are extremely pleased to obtain early and broadly applicable RNAi IP assets, including the Li & Kirby, Pachuk I, and Giordano patent families, which have very early priority dates going back to 1998. Clearly, these new IP elements complement our existing fundamental IP, such as the Crooke, Tuschl II, and Kreutzer-Limmer patent families, as well as many others - all of which Alnylam holds exclusively."

Amongst over 100 active patent filings, the Nucleonics IP estate includes several early filed patent applications, including:

-- the Li & Kirby patent family (USSN:10/038,984, among other applications in the family) from the Medical College of Georgia, which covers methods for attenuating the expression of a target gene in vertebrates using a double stranded RNA (dsRNA);
-- the Pachuk I patent family (USSN:10/009,134, among other applications in the family) from Wyeth, which covers double stranded RNA to reduce gene target expression, methods of inhibiting the function of a protein with dsRNA and multi-targeting dsRNAs, which target either the coding or non-coding portions of a gene; and
-- the Giordano patent family (USSN:10/762,395, among other applications in the family), which covers methods of down-regulating expression of gene targets using RNAi, methods of achieving intracellular RNAi for gene expression regulation and therapeutic applications, and methods of identifying dsRNA delivery complexes with reduced toxicity.

Rodman & Renshaw, LLC advised Alnylam on this transaction.

About Alnylam Intellectual Property (IP)

Alnylam's IP estate includes issued, allowed, or granted fundamental patents in many of the world's major pharmaceutical markets that claim the broad structural and functional properties of RNAi therapeutic products. These include:

-- the Crooke Patents (U.S. Patent Nos. 5,898,031, 6,107,094, 7,432,249, 7,432,250 and EP 0928290) issued in over 12 countries and licensed exclusively from Isis Pharmaceuticals, Inc. to Alnylam for RNAi therapeutics, which cover compositions, methods, and uses of modified oligonucleotides to inactivate a target mRNA mediated by a double stranded RNase, such as "RISC," which is the cellular enzyme complex that mediates RNAi;
-- the Kreutzer-Limmer I '623 patent (EP 1144623) granted in August 2002, maintained in amended form in June 2006 and owned by Alnylam, which covers methods, medicaments, and uses of siRNAs having, among other structural features, a length of 15 to 21 base pairs;
-- the Kreutzer-Limmer I '945 patent (EP 1214945) granted in June 2005 and owned by Alnylam, which covers compositions, methods, and uses of siRNAs with a length between 15 and 49 nucleotides;
-- the Kreutzer-Limmer I '167 patent (DE 10080167) granted in October 2007 and owned by Alnylam, which covers pharmaceutical compositions and uses of siRNAs with a length between 15 and 49 nucleotides that target certain broad categories of mammalian genes;
-- the Kreutzer-Limmer I '235 patent (DE 10066235), granted in January 2008 and owned by Alnylam, which covers methods, uses, and medicaments of siRNAs, with a length between 15 and 49 nucleotides, expressed through a vector;
-- the Kreutzer-Limmer II '061 patent (EP 1352061), granted in May 2006 and owned by Alnylam, which covers therapeutic compositions, methods, and uses of siRNA and derivatives directed toward over 125 disease targets;
-- the Tuschl II '704 patent (U.S. Patent No. 7,056,704) issued in June 2006 and exclusively licensed to Alnylam from the Max Planck Society, which broadly covers methods of making siRNAs to silence any and all disease targets;
-- the Tuschl II '196 patent (U.S. Patent No. 7,078,196) issued in July 2006 and exclusively licensed to Alnylam from the Max Planck Society, which broadly covers methods of making siRNAs with or without chemical modifications;
-- the Tuschl II '044 patent (EP 1407044), granted in January 2008 and exclusively licensed to Alnylam from the Max Planck Society, which broadly covers compositions, methods, and uses of siRNAs;
-- the Tuschl II patent (JP 4 095 895) granted in May 2008 in Japan and exclusively licensed to Alnylam from the Max Planck Society, which broadly covers compositions, methods, uses, and systems of siRNAs;
-- many divisional and continuing patent applications pending of the aforementioned issued or granted patents and additional patent applications pending, including patents and patent applications covering inventions by Fire & Mello (U.S. Patent No. 6,506,559), Glover, Li & Kirby, Pachuk, Tuschl, Hannon, Giordano, and Kay.

In addition to fundamental patents, Alnylam is the exclusive licensee in the field of RNAi therapeutics for more than 150 issued chemistry patents owned or controlled by Isis Pharmaceuticals broadly covering chemical modifications, including motifs and patterns of modifications of oligonucleotides, including RNAi therapeutics. These patents include:

-- phosphorothioate and 2'-O-methyl modifications of oligonucleotides (Buhr, U.S. Patent No. 6,476,205);
-- 2'-Ribose modifications of oligonucleotides (Cook, U.S. Patent Nos. 5,670,633; 6,005,087; 6,531,584; and 7,138,517);
-- chemical conjugates of oligonucleotides (Manoharan, U.S. Patent No. 6,153,737); and,
-- "overhang," "blunt-end," and nucleotide pairing design motifs (Woppmann et al., UK 2417727), which is owned by Alnylam.

In addition to fundamental and chemistry patents, Alnylam is also the exclusive licensee in the field of RNAi therapeutics for certain delivery patents, including those owned and controlled by Tekmira Pharmaceuticals, Inc. covering delivery of oligonucleotides, including RNAi therapeutics, with liposomal formulations. These patents include:

-- formulations of oligonucleotides, including siRNAs, in cationic liposomes (Wheeler, U.S. Patent Nos. 5,976,567 and 6,815,432; and Semple, U.S. Patent No. 6,858,225).

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 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, and Kyowa Hakko. 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 LLC, 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://www.alnylam.com.

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, various important factors, including the company's ability to successfully prosecute, maintain and enforce its patents, including the patents acquired from Nucleonics, 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.

CONTACT: Alnylam Pharmaceuticals, Inc.
Cynthia Clayton (Investors), 617-551-8207
or
Yates Public Relations
Kathryn Morris (Media), 845-635-9828

Source: Alnylam Pharmaceuticals, Inc.