Regulus Therapeutics Receives Exclusive License for Intellectual Property on Immuno-inflammatory microRNAs from the California Institute of Technology

Regulus Therapeutics Inc., founded by Alnylam Pharmaceuticals, Inc. (Nasdaq: ALNY) and Isis Pharmaceuticals, Inc. (Nasdaq: ISIS), announced today that it has obtained exclusive rights from the California Institute of Technology to inventions made in the laboratory of David Baltimore, Ph.D. covering methods and compositions for modulating microRNA-146 and microRNA-155. Dr. Baltimore and his colleagues have shown that microRNAs miR-146 and miR-155 are key mediators of the inflammatory response. Modulation of these microRNAs could lead to a new method of treating immune-inflammatory disease.

"We are very pleased to obtain exclusive worldwide rights to this intellectual property from California Institute of Technology, as it builds on our strategy of consolidating and controlling the key intellectual property needed for the development of microRNA therapeutics,” said Kleanthis G. Xanthopoulos, Ph.D., President and Chief Executive Officer of Regulus. "Access to this intellectual property allows us to apply our expertise in the biology of microRNAs and nucleic acid chemistry to translate academic discoveries into novel microRNA-based therapeutics for inflammatory diseases.”

The licensed technology relates to the discovery that miR-155 is induced during the macrophage inflammatory response and the characterization of miR-155 as a common target of a broad range of inflammatory mediators [O’Connell et al. (2007) PNAS 104: 1604-1609; O’Connell et al. (2007) JEM 205:585-594]. As miR-155 is known to function as an oncogene, these observations suggest a link between inflammation and cancer.

Also included in the licensed technology is the discovery that miR-146 is induced, in an NF-kB-dependent manner, in response to proinflammatory mediators [Taganov et al. (2006) PNAS 103:12481-12486]. These findings suggest that modulation of miR-146 may be of therapeutic benefit in treating diseases characterized by excessive activation of innate immunity signaling.

About microRNAs

The discovery of microRNA in humans is one of the most exciting scientific breakthroughs in the last decade. microRNAs are small RNA molecules, typically 20 to 25 nucleotides in length, that do not encode proteins but instead regulate gene expression. Nearly 700 microRNAs have been identified in the human genome, and more than one-third of all human genes are believed to be regulated by microRNAs. As a single microRNA can regulate entire networks of genes, these new molecules are considered the master regulators of the genome. microRNAs have been shown to play an integral role in numerous biological processes including the immune response, cell-cycle control, metabolism, viral replication, stem cell differentiation and human development. Many microRNAs are conserved across multiple species indicating the evolutionary importance of these molecules as modulators of critical biological pathways. Indeed, microRNA expression or function has been shown to be significantly altered in many disease states, including cancer, heart failure and viral infections. Targeting microRNAs opens the possibility of a novel class of therapeutics and a unique approach to treating disease by modulating entire biological pathways.

About Regulus Therapeutics Inc.

Regulus Therapeutics is a biopharmaceutical company leading the discovery of innovative new medicines based on microRNAs. Regulus is targeting microRNAs as a new class of therapeutics by working with a broad network of academic collaborators and leveraging oligonucleotide drug discovery and development expertise from its founding companies Alnylam Pharmaceuticals (Nasdaq:ALNY) and ISIS Pharmaceuticals (Nasdaq:ISIS). Regulus is advancing microRNA therapeutics towards the clinic in several areas including hepatitis C infection, cardiovascular disease and fibrosis, oncology, and immunology and inflammation. Regulus intellectual property estate contains both the fundamental and core patents in the field as well as over 600 patents and more than 300 pending patent applications pertaining primarily to chemical modifications of oligonucleotides targeting microRNAs for therapeutic applications. In 2008, Regulus entered into a major alliance with GlaxoSmithKline to discover and develop microRNA therapeutics for immuno-inflammatory diseases. For more information, visit www.regulusrx.com.

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 Kirin. 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 Kirin, 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 and Isis are joint owners of Regulus Therapeutics Inc., a company focused on the discovery, development, and commercialization of microRNA-based therapeutics. Founded in 2002, Alnylam maintains headquarters in Cambridge, Massachusetts. For more information, please visit www.alnylam.com.

About Isis Pharmaceuticals, Inc.

Isis is exploiting its expertise in RNA to discover and develop novel drugs for its product pipeline and for its partners. The Company has successfully commercialized the world's first antisense drug and has 21 drugs in development. Isis’ drug development programs are focused on treating cardiovascular, metabolic and severe neurodegenerative diseases and cancer. Isis’ partners are developing antisense drugs invented by Isis to treat a wide variety of diseases. Isis and Alnylam Pharmaceuticals are joint owners of Regulus Therapeutics Inc., a company focused on the discovery, development and commercialization of microRNA therapeutics. Isis also has made significant innovations beyond human therapeutics resulting in products that other companies, including Abbott, are commercializing. As an innovator in RNA-based drug discovery and development, Isis is the owner or exclusive licensee of over 1,600 issued patents worldwide. Additional information about Isis is available at www.isispharm.com.

Forward-Looking Statements

This press release includes forward-looking statements regarding the future therapeutic and commercial potential of Regulus’, Alnylam’s, and Isis’ business plans, technologies and intellectual property related to microRNA therapeutics being discovered and developed by Regulus. Any statement describing Regulus’, Alnylam’s, and Isis’ goals, expectations, financial or other projections, intentions or beliefs is a forward-looking statement and should be considered an at-risk statement, including those statements that are described as such parties’ goals. Such statements are subject to certain risks and uncertainties, particularly those inherent in the process of discovering, developing and commercializing drugs that are safe and effective for use as human therapeutics, and in the endeavor of building a business around such products. Such parties’ forward-looking statements also involve assumptions that, if they never materialize or prove correct, could cause their results to differ materially from those expressed or implied by such forward-looking statements. Although these forward-looking statements reflect the good faith judgment of the management of each such party, these statements are based only on facts and factors currently known by Regulus’, Alnylam’s, and Isis’ as the case may be. As a result, you are cautioned not to rely on these forward-looking statements. These and other risks concerning Regulus’, Alnylam’s, and Isis’ programs are described in additional detail in Alnylam’s and Isis’ annual reports on Form 10-K for the year ended December 31, 2008, and their most recent quarterly reports on Form 10-Q which are on file with the SEC. Copies of these and other documents are available from Alnylam or Isis.