Regulus Therapeutics and GlaxoSmithKline Establish New Collaboration to Develop and Commercialize microRNA Therapeutics Targetin

Regulus Therapeutics and GlaxoSmithKline Establish New Collaboration to Develop and Commercialize microRNA Therapeutics Targeting miR-122

- miR-122 Represents a Novel "Host Factor" Strategy for Treatment of Hepatitis C Infection -

- Further Demonstration of Regulus Leadership in microRNA Science, Technology and Intellectual Property -

CARLSBAD, Calif.--(BUSINESS WIRE)--Regulus Therapeutics Inc. today announced the establishment of a new collaboration with GlaxoSmithKline (GSK) to develop and commercialize microRNA therapeutics targeting microRNA-122 in all fields with Hepatitis C Viral infection (HCV) as the lead indication. Under the terms of the new collaboration, Regulus will receive additional upfront and early-stage milestone payments with the potential to earn more than $150 million in miR-122-related combined payments, and tiered royalties up to double digits on worldwide sales of products.

"This new collaboration with GSK demonstrates the clear scientific leadership that Regulus has established in advancing a whole new frontier of pharmaceutical research. microRNA therapeutics target the pathways of human diseases, not just single disease targets, and hold considerable promise as novel therapies across a broad range of unmet medical needs," said Kleanthis G. Xanthopoulos, Ph.D., President and Chief Executive Officer of Regulus. "It also further validates Regulus' microRNA product platform built on fundamental biology of human diseases and intellectual property, and also extends the therapeutic scope of our existing collaboration formed with GSK in 2008. Furthermore, the funding from this alliance supports Regulus' efforts in advancing high impact, novel medicines based on microRNA biology to patients."

The collaboration provides GSK with access to Regulus' comprehensive and robust intellectual property estate. Regulus exclusively controls patent rights covering miR-122 antagonists and their use as HCV therapeutics in the United States, Europe, and Japan, including but not limited to the patent families which encompass: the ‘Sarnow' patent pertaining to the method of use of anti-miR-122 to inhibit HCV replication, the ‘Esau' patent application claiming the use of anti-miRs targeting miR-122 as inhibitory agents, the ‘Tuschl III' patent claiming composition of matter for miR-122 and complementary oligonucleotides, and the ‘Manoharan' patent claiming antagomirs, including antagomirs targeting miR-122.

miR-122 is a liver-expressed microRNA that has been shown to be a critical endogenous "host factor" for the replication of HCV, and anti-miRs targeting miR-122 have been shown to block HCV infection (Jopling et al. (2005) Science 309, 1577-81). In earlier work, scientists at Alnylam and Isis demonstrated the ability to antagonize miR-122 in vivo using chemically modified single-stranded anti-miR oligonucleotides. Further, work by Regulus scientists and collaborators showed that inhibiting miR-122 results in significant inhibition of HCV replication in human liver cells, suggesting that antagonism of miR-122 may comprise a novel "host factor" therapeutic strategy. Regulus scientists have shown in multiple preclinical studies a robust HCV antiviral effect following inhibition of miR-122. Regulus plans to identify a clinical development candidate in the second half of 2010 and file an investigational new drug (IND) application in 2011.

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 Hepatitis C Virus (HCV)

HCV infection is a disease with an estimated prevalence of 170 million patients worldwide, with more than 3 million patients in the United States. HCV shows significant genetic variation in worldwide populations due to its frequent rates of mutation and rapid evolution. There are six genotypes of HCV, with several subtypes within each genotype, which vary in prevalence across the different regions of the world. The response to treatment varies from individual to individual underscoring the inadequacy of existing therapies and highlights the need for combination therapies that not only target the virus but endogenous "host factors" as well. Strategies that include the Regulus miR-122 antagonist as part of emerging combination therapies to shorten duration of treatment and interferon use, improve the safety profile and sustained virologic response (SVR), increase the barrier to drug resistance, and address difficult-to-treat genotypes hold significant potential to expand the limited therapies available to physicians treating HCV patients.

About Regulus Therapeutics Inc.

Regulus Therapeutics is a biopharmaceutical company leading the discovery and development 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, fibrosis, oncology, immuno-inflammatory diseases, and metabolic diseases. 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

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, including statements regarding expectations around the relationship between GSK and 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' management 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.