Sanofi-aventis and Regeneron Pharmaceuticals announced the discontinuation of the Phase 3 trial that evaluated aflibercept (VEGF Trap) plus gemcitabine versus placebo plus gemcitabine for the first-line treatment of metastatic pancreatic cancer (VANILLA), based on the recommendations by an Independent Data Monitoring Committee (IDMC).

PARIS, France, and TARRYTOWN, NY, USA I, September 11, 2009 I Sanofi-aventis (Euronext: SAN and NYSE: SNY) and Regeneron Pharmaceuticals, Inc. (Nasdaq: REGN – News) today announced the discontinuation of the Phase 3 trial that evaluated aflibercept (VEGF Trap) plus gemcitabine versus placebo plus gemcitabine for the first-line treatment of metastatic pancreatic cancer (VANILLA), based on the recommendations by an Independent Data Monitoring Committee (IDMC). As part of a planned interim efficacy analysis, the IDMC determined that the addition of aflibercept to gemcitabine would be unable to demonstrate a statistically significant improvement in the primary endpoint of overall survival compared to placebo plus gemcitabine in this study. The types and frequencies of adverse events reported on the combination arm with aflibercept were generally as anticipated.

With the closure of the study, a detailed analysis of the efficacy and safety results will be conducted by the companies and results will be presented at a future medical meeting. Sanofi-aventis and Regeneron have notified the study investigators and appropriate regulatory authorities of the decision to discontinue the study. Patients in the study will continue to be provided access to aflibercept at the determination of the study investigators in consultation with the patients.

Metastatic pancreatic cancer is among the most intractable cancers. Clinical development of new therapies, including anti-VEGF agents, has been generally characterized by a failure to achieve significant incremental clinical benefit over existing treatments.

"We are disappointed with the result of this study and we will continue our efforts to bring new and effective treatments for these patients," said Dr. Marc Cluzel, Senior Vice President, Research and Development sanofi-aventis. "We remain committed to the other ongoing Phase 3 trials of aflibercept in colorectal cancer, non-small cell lung cancer, and hormone-refractory metastatic prostate cancer."

Three Phase 3 studies continue, each of which is currently over 70 percent enrolled:

* VELOUR study: 2nd-line metastatic colorectal cancer in combination with fluorouracil, leucovorin, and irinotecan (FOLFIRI)
* VITAL study: 2nd-line non-small cell lung cancer in combination with docetaxel
* VENICE study: 1st-line hormone-refractory metastatic prostate cancer in combination with docetaxel and prednisone

About Pancreatic Cancer

Each year in the United States, more than 42,000 individuals are diagnosed with pancreatic cancer and over 35,000 die. The prognosis is generally poor; less than five percent of those diagnosed are still alive five years after diagnosis. Gemcitabine is considered the standard backbone of first-line treatment in patients with first-line metastatic pancreatic cancer.

About Aflibercept

Aflibercept is an anti-angiogenesis inhibitor with a unique mechanism of action. This fusion protein binds all forms of Vascular Endothelial Growth Factor-A (VEGF-A), as well as VEGF-B and placental growth factor (PIGF), additional angiogenic growth factors that appear to play a role in tumor angiogenesis and inflammation. Aflibercept has been shown to bind VEGF-A, VEGF-B, and PlGF with higher affinity than their natural receptors.

About sanofi-aventis

Sanofi-aventis, a leading global pharmaceutical company, discovers, develops, and distributes therapeutic solutions to improve the lives of everyone. Sanofi-aventis is listed in Paris (EURONEXT PARIS: SAN) and in New York (NYSE: SNY – News).

About Regeneron Pharmaceuticals, Inc.

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 clinical trials for the potential treatment of cancer, eye diseases, inflammatory diseases, and pain, and has preclinical programs in other diseases and disorders. Additional information about Regeneron and recent news releases are available on Regeneron’s web site at www.regeneron.com.