Sanofi-aventis (EURONEXT : SAN and NYSE : SNY) and Regeneron Pharmaceuticals, Inc. (Nasdaq: REGN) announced today that they have amended their Vascular Endothelial Growth Factor (VEGF) Trap collaboration agreement to include Japan.  The companies will now collaborate on the joint development and commercialization of the VEGF Trap throughout the world in all indications, except for intraocular delivery to the eye.

As remuneration for the inclusion of Japan into the VEGF Trap collaboration, Regeneron will receive an upfront payment of $ 25 million, milestone payments related to potential approvals in Japan, and royalties on sales of the VEGF Trap in Japan.  Sanofi-aventis will lead and fund the development of the VEGF Trap in Japan.

Under the collaboration agreement, sanofi-aventis will pay 100% of VEGF Trap development expenses; and, following commercialization of a VEGF Trap product, Regeneron will repay 50% of the development costs paid by sanofi-aventis out of VEGF Trap profits, including the Japanese royalty.

Role of VEGF in the Tumor Growth
Vascular Endothelial Growth Factor (VEGF) is a naturally occurring protein in the body whose normal role is to trigger formation of new blood vessels (angiogenesis) to support the growth of the body’s tissues and organs.  It has also been associated with the abnormal growth of new blood vessels surrounding tumors to support their expansion. Blocking tumor-associated angiogenesis has been shown to prevent tumor growth in a variety of clinical and pre-clinical evaluations, with the most widely recognized and highly validated results achieved based on approaches that block VEGF. The VEGF Trap has been shown in pre-clinical studies to block the action of VEGF, thereby blocking the abnormal growth of blood vessels.


About Sanofi-Aventis
Sanofi-aventis is the world’s third largest pharmaceutical company, ranking number one in Europe. Backed by a world-class R&D organization, sanofi-aventis is developing leading positions in seven major therapeutic areas: cardiovascular, thrombosis, oncology, metabolic disorders, central nervous system, internal medicine, and vaccines. Sanofi-aventis is listed in Paris (EURONEXT : SAN) and in New York (NYSE : SNY).


Forward-Looking Statements
This press release contains forward-looking statements as defined in the Private Securities Litigation Reform Act of 1995. Forward-looking statements are statements that are not historical facts. These statements include financial projections and estimates and their underlying assumptions, statements regarding plans, objectives and expectations with respect to future operations, products and services, and statements regarding future performance. Forward-looking statements are generally identified by the words “expect,” “anticipates,” “believes,” “intends,” “estimates,” “plans” and similar expressions. Although sanofi-aventis’ management believes that the expectations reflected in such forward-looking statements are reasonable, investors are cautioned that forward-looking information and statements are subject to various risks and uncertainties, many of which are difficult to predict and generally beyond the control of sanofi-aventis, that could cause actual results and developments to differ materially from those expressed in, or implied or projected by, the forward-looking information and statements. These risks and uncertainties include those discussed or identified in the public filings with the SEC and the AMF made by sanofi-aventis, including those listed under “Risk Factors” and “Cautionary Statement Regarding Forward-Looking Statements” in sanofi-aventis’ annual report on Form 20-F for the year ended December 31, 2004. Other than as required by applicable law, sanofi-aventis does not undertake any obligation to update or revise any forward-looking information or statements.
Sanofi-aventis subsidiaries in the United States include Sanofi-Synthelabo Inc., Aventis Pharmaceuticals Inc. and Sanofi Pasteur Inc.


About Regeneron
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.


Forward-Looking Statements
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 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 agreement with the sanofi-aventis Group, 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-K for the year ended December 31, 2004 and Form 10-Q for the quarter ended September 30, 2005.  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.