Alnylam Earns Milestone Payment from GlaxoSmithKline in VaxiRNA Collaboration on Flu Vaccine Production

Alnylam Earns Milestone Payment from GlaxoSmithKline in VaxiRNA Collaboration on Flu Vaccine Production

Cynthia Clayton, 617-551-8207Vice President, Investor Relations andCorporate CommunicationsorSpectrumAmanda Sellers (Media), 202-955-6222 x2597

(Nasdaq: ALNY), a leading RNAi therapeutics company, announced today that it has earned a development milestone payment from GlaxoSmithKline (GSK), totaling $3.2 million. The milestone payment is related to progress in the companies’ collaboration on the use of VaxiRNA™ technology for the production of GSK influenza vaccine. Alnylam’s VaxiRNA platform uses RNAi technology for the enhanced manufacturing of vaccine products.

“We have made important progress with GSK in advancing Alnylam’s VaxiRNA technology, and are pleased to have achieved a key milestone in our collaborative effort,” said Rachel Meyers, Ph.D., Vice President, Research and RNAi Lead Development. “At Alnylam, we continue to pioneer innovative applications of our RNAi platform that could have a transformative impact in medicine and the biopharmaceutical industry at large. Our VaxiRNA platform is representative of this strategy, where RNAi technology is being used to increase virus titers in the production of vaccine products. With GSK, we are applying RNAi technology with the aim to enhance influenza vaccine production in cell culture. We look forward to continuing our efforts in this strategic collaboration.”

Alnylam’s VaxiRNA platform applies siRNA for the silencing of specific genes that limit or prevent efficient manufacturing of vaccine antigens, including those produced in cell culture and in eggs. The VaxiRNA platform stems from work Alnylam has performed as part of its Alnylam Biotherapeutics efforts, where RNAi technology has been applied to improve the manufacturing of biotherapeutic products, such as recombinant proteins and monoclonal antibodies. Alnylam and GSK formed their collaboration in the fourth quarter of 2011. The effort is focused initially on influenza vaccine production in cell culture systems. Under the terms of the agreement, GSK will provide research funding and certain milestone payments to Alnylam, such as the $3.2 million received this quarter. If successfully applied in the manufacturing of commercial product, Alnylam will receive payments on unit product sales of commercialized vaccine product. In addition, GSK has obtained an option for VaxiRNA applications toward two additional vaccine products.

Alnylam is applying RNAi technology to improve the manufacturing processes for vaccines in an effort called VaxiRNA. With VaxiRNA, Alnylam is using siRNA that silence specific genes in vaccine production systems, such as cells or eggs, which limit or prevent the efficient manufacture of vaccine products. New innovations in vaccine manufacturing are needed to enable the scale and speed of global immunization for a number of pathogens. In 2011, Alnylam formed a VaxiRNA partnership with GlaxoSmithKline for influenza vaccine production.

RNAi (RNA interference) represents a breakthrough in understanding how genes are turned on and off in cells, and adds a new approach to drug discovery and development. Its discovery represents a promising and rapidly advancing frontier 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. This process can be used to enhance the manufacturing of vaccines or medicines. In addition, 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 might be possible in the future. Small interfering RNA (siRNA), 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.

Alnylam is a biopharmaceutical company developing novel therapeutics based on RNA interference, or RNAi. The company is leading the translation of RNAi as a new class of innovative medicines with a core focus on RNAi therapeutics for the treatment of genetically defined diseases, including ALN-TTR for the treatment of transthyretin-mediated amyloidosis (ATTR), ALN-AT3 for the treatment of hemophilia, ALN-PCS for the treatment of severe hypercholesterolemia, ALN-HPN for the treatment of refractory anemia, and ALN-TMP for the treatment of hemoglobinopathies. As part of its “Alnylam 5x15” strategy, the company expects to have five RNAi therapeutic products for genetically defined diseases in clinical development, including programs in advanced stages, on its own or with a partner by the end of 2015. Alnylam has additional partnered programs in clinical or development stages, including ALN-RSV01 for the treatment of respiratory syncytial virus (RSV) infection, ALN-VSP for the treatment of liver cancers, and ALN-HTT for the treatment of Huntington’s disease. The company’s leadership position on RNAi therapeutics and intellectual property have enabled it to form major alliances with leading companies including Merck, Medtronic, Novartis, Biogen Idec, Roche, Takeda, Kyowa Hakko Kirin, Cubist, and Ascletis. In addition, Alnylam and Isis co-founded Regulus Therapeutics Inc., a company focused on discovery, development, and commercialization of microRNA therapeutics; Regulus has formed partnerships with GlaxoSmithKline and Sanofi. Alnylam has also formed Alnylam Biotherapeutics, a division of the company focused on the development of RNAi technologies for applications in biologics manufacturing, including recombinant proteins and monoclonal antibodies. Alnylam’s VaxiRNA™ platform applies RNAi technology to improve the manufacturing processes for vaccines; GlaxoSmithKline is a collaborator in this effort. Alnylam scientists and collaborators have published their research on RNAi therapeutics in over 100 peer-reviewed papers, including many in the world’s top scientific journals such as , , , and . Founded in 2002, Alnylam maintains headquarters in Cambridge, Massachusetts. For more information, please visit

Various statements in this release concerning Alnylam’s future expectations, plans and prospects, including without limitation, Alnylam’s views with respect to the potential for VaxiRNA to apply RNAi technology to improve the manufacturing process for vaccines, its expectations regarding the receipt of research funding, milestone payments and payments on unit product sales under its collaboration with GSK, as well as Alnylam’s expectations with respect to its “Alnylam 5x15” product strategy, 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, without limitation, Alnylam’s ability to successfully apply RNAi technology to improve the manufacturing process for vaccines, including in connection with its GSK collaboration, demonstrate the efficacy and safety of its drug candidates in pre-clinical and human clinical trials, and establish and maintain strategic business alliances and new business initiatives, 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.