Astellas to Pay $295 Million to Extend License of Regeneron's VelocImmune® Antibody Technology through 2023

TARRYTOWN, N.Y.andTOKYO,July 28/PRNewswire-FirstCall/ -- Regeneron Pharmaceuticals, Inc. ("Regeneron"; Nasdaq:REGN) and Astellas Pharma Inc. ("Astellas"; Headquarters:Tokyo, Japan; President & CEO:Masafumi Nogimori) announced today that Astellas has extended through 2023 the non-exclusive license agreement that allows Astellas to utilize Regeneron'sVelocImmune®technology in its internal research programs to discover fully human monoclonal antibody product candidates.

Astellas will pay$165 millionupfront and another$130 millioninJune 2018unless it terminates the agreement prior to that date.  Upon commercialization of any antibody products discovered utilizingVelocImmune, Astellas will pay a mid-single-digit royalty on product sales.

InMarch 2007, Astellas and Regeneron entered into a six-yearVelocImmunelicense agreement pursuant to which Astellas made license payments of$20 millionper year in 2007 through 2010.  This amendment supersedes the original agreement and as such, Astellas will no longer make annual license payments in 2011 and 2012.  Approximately 20 monoclonal antibody projects usingVelocImmunetechnology are ongoing at Astellas and Agensys, Inc., a U.S. affiliate of Astellas.

"VelocImmuneis the centerpiece of Regeneron's suite of technologies for the discovery and development of fully human monoclonal antibodies," said George D. Yancopoulos, M.D., Ph.D., President of Regeneron Research Laboratories and Regeneron's Chief Scientific Officer.  "We are pleased that Astellas, a company with a clear strategic commitment to developing therapeutic antibodies, has elected to continue to utilize theVelocImmuneplatform for its internal development programs."

"We are excited about this extension of the license agreement with Regeneron," said Shinichi Tsukamoto, Ph.D., Astellas' Senior Vice President, Drug Discovery Research.  "As described in our recently announced mid-term management plan toward FY2014, Astellas is putting the highest strategic priority on the development of antibody drugs, and VelocImmunewill continue to be the indispensable technology for our antibody drug development program."

Regeneron'sVelocImmunetechnology offers the potential to increase dramatically the speed and efficiency of discovering fully-human, therapeutic monoclonal antibodies.  TheVelocImmuneplatform generates fully human monoclonal antibodies (hMAbs) to address clinically relevant targets of therapeutic interest.  TheVelocImmunemouse, unlike other hMAb mice, mounts a robust immune response that is virtually indistinguishable from that of a wild type mouse, resulting in a reliable and efficient platform for discovering fully human monoclonal antibodies.

Astellas Pharma Inc., located inTokyo, Japan, is a pharmaceutical company dedicated to improving the health of people around the world through the provision of innovative and reliable pharmaceutical products.  Astellas has approximately 15,000 employees worldwide. The organization is committed to becoming a global category leader by rapidly establishing a business model in urology, immunology & infectious diseases, neuroscience, DM complications & metabolic diseases and oncology.  Astellas has discovered a treatment for over-active bladder (OAB), Vesicare®  (solifenacin succinate) and an immunosuppressant, Prograf® (tacrolimus), which have enabled Astellas to become an established leader in both Urology and Transplant.  For more information on Astellas Pharma Inc., please visit Astellas' website athttp://www.astellas.com/en.

Regeneron is a fully integrated biopharmaceutical company that discovers, develops, and commercializes medicines for the treatment of serious medical conditions.  In addition to ARCALYST® (rilonacept) Injection for Subcutaneous Use, its first commercialized product, Regeneron has therapeutic candidates in Phase 3 clinical trials for the potential treatment of gout, diseases of the eye (wet age-related macular degeneration and central retinal vein occlusion), and certain cancers.  Additional therapeutic candidates developed from proprietary Regeneron technologies for creating fully human monoclonal antibodies are in earlier stage development programs in rheumatoid arthritis and other inflammatory conditions, pain, cholesterol reduction, allergic and immune conditions and cancer.  Additional information about Regeneron and recent news releases are available on Regeneron's web site atwww.regeneron.com.

This news release includes forward-looking statements about Regeneron and its products, development programs, finances, and business, all of which involve a number of risks and uncertainties.  These include, among others, risks and timing associated with preclinical and clinical development of Regeneron's drug candidates, determinations by regulatory and administrative governmental authorities which may delay or restrict Regeneron's ability to continue to develop or commercialize its product and drug candidates, competing drugs that are superior to Regeneron's product and drug candidates, uncertainty of market acceptance of Regeneron's product and drug candidates, unanticipated expenses, the availability and cost of capital, the costs of developing, producing, and selling products, the potential for any license or collaboration agreement, including Regeneron's agreements with Astellas, the sanofi-aventis Group and Bayer HealthCare, to be canceled or terminated without any product success, and risks associated with third party intellectual property.  A more complete description of these and other material risks can be found in Regeneron's filings with the United States Securities and Exchange Commission (SEC), including its Form 10-K for the year endedDecember 31, 2009and Form 10-Q for the quarter endedMarch 31, 2010.  Regeneron does not undertake any obligation to update publicly any forward-looking statement, whether as a result of new information, future events, or otherwise, unless required by law.

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