PRESS RLEASE: Phase 3 Oncology Program for Aflibercept (VEGF Trap) Initiated by Regeneron and sanofi-aventis

Phase 3 Oncology Program for Aflibercept (VEGF Trap) Initiated by Regeneron and sanofi-aventis

TARRYTOWN, N.Y. -- Aug 23, 2007 - Regeneron Pharmaceuticals, Inc. (Nasdaq: REGN) today announced the initiation of two Phase 3 trials evaluating the safety and efficacy of aflibercept (VEGF Trap) in combination with standard chemotherapy regimens in patients with prostate cancer and non-small cell lung cancer (NSCLC). Aflibercept is an anti-angiogenic agent targeting Vascular Endothelial Growth Factor (VEGF), currently being developed by Regeneron in collaboration with sanofi-aventis. These two trials will be double-blind and placebo-controlled.

Sanofi-aventis will provide an update of the broad-based clinical development program planned for aflibercept, and additional details on these two trials, at its R&D Day meeting scheduled to be held in Paris, France on September 17, 2007. That meeting will be webcast and will be accessible at their corporate website: www.sanofi-aventis.com [1]. 

Information on the two studies discussed will be posted on the Internet at www.clinicaltrials.gov [2].

About Aflibercept (VEGF Trap) in Oncology

Aflibercept is a fully human soluble VEGF receptor fusion protein with a unique mechanism of action. It is a potent, investigational angiogenesis inhibitor, which binds VEGF-A more tightly than monoclonal antibodies. It blocks all VEGF-A isoforms plus placental growth factor (PIGF), another angiogenic growth factor that appears to play a role in tumor angiogenesis. Aflibercept has a relatively long half-life of approximately two weeks. Other anti-VEGF agents have been approved for certain cancer indications and neovascular age-related macular degeneration.

About Regeneron Pharmaceuticals

Regeneron is a biopharmaceutical company that discovers, develops, and intends to commercialize therapeutic medicines for the treatment of serious medical conditions. Regeneron has therapeutic candidates for the potential treatment of cancer, eye diseases, and inflammatory diseases and has preclinical programs in other diseases and disorders. Additional information about Regeneron and recent news releases are available on Regeneron's worldwide web site at www.regeneron.com [3].

Forward Looking Statements for Regeneron

This news release discusses historical information and includes forward-looking statements about Regeneron and its products, programs, finances, and business, all of which involve a number of risks and uncertainties, such as risks associated with preclinical and clinical development of our drug candidates, determinations by regulatory and administrative governmental authorities which may delay or restrict our ability to continue to develop or commercialize our drug candidates, competing drugs that are superior to our product candidates, unanticipated expenses, the availability and cost of capital, the costs of developing, producing, and selling products, the potential for any collaboration agreement, including our agreements with the sanofi-aventis Group and Bayer HealthCare, to be canceled or to terminate without any product success, risks associated with third party intellectual property, and other material risks. 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-Q for the quarter ended June 30, 2007. 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.