Alnylam Pharmaceuticals, Inc. (Nasdaq: ALNY), a leading RNAi therapeutics company, announced today that the United States Patent and Trademark Office (USPTO) has maintained key claims in the company’s KSP RNAi patent (US Patent No. 7,718,629) in interference proceedings. The interference was declared on February 28, 2011, between Alnylam’s patent and a patent application (US Patent Application No. 11/807,872) filed by Protiva Biotherapeutics Inc., a subsidiary of Tekmira Pharmaceuticals Corporation, which included a pending claim to an siRNA sequence that was identical to one described in the earlier filed Alnylam patent. The next phase of the interference proceedings will examine the respective priority date for each of the parties’ claims consistent with current U.S. patent law’s “first to invent” statute. “The maintained claims in the KSP RNAi patent cover the siRNA composition of matter used in ALN-VSP and define the relevant claims for further development and commercialization of this promising RNAi therapeutic for liver cancers,” said Laurence Reid, Senior Vice President and Chief Business Officer of Alnylam. “We look forward to the start of the priority phase in these proceedings and believe that our patent will prevail at this stage of the interference.” The KSP RNAi patent claims the siRNA sequence used in Alnylam’s ALN-VSP investigational drug product, which has completed a Phase I clinical study and which the company intends to partner prior to initiation of Phase II trials. In addition to the KSP RNAi patent, Alnylam has additional issued patents that specifically cover siRNA sequences in the ALN-VSP drug product (US Patent Nos. 7,947,659 and 7,919,473), and other patents pending. Further, the company maintains an exclusive position on a broad intellectual property estate covering RNAi therapeutics including fundamental patents covering siRNA architecture, chemistry patents covering siRNA modifications, and delivery patents covering conjugates and lipid nanoparticles (LNP), including the Semple and Wheeler LNP patent families that broadly cover the formulation used in ALN-VSP.