ZALTRAP (aflibercept) Receives CHMP Positive Opinion in the European Union for Previously Treated Metastatic Colorectal Cancer Paris, France and Tarrytown, NY

ZALTRAP (aflibercept) Receives CHMP Positive Opinion

in the European Union for Previously

Treated Metastatic Colorectal

Paris, France and Tarrytown, NY November 16, 2012 Sanofi (EURONEXT: SAN and

NYSE: SNY) and Regeneron Pharmaceuticals, Inc. (NASDAQ: REGN) today announced that the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) adopted a positive opinion and recommended the granting of

marketing authorization for ZALTRAP (aflibercept) 25mg/ml concentrate for solution for infusion in combination

with irinotecan/5-fluorouracil/folinic acid (FOLFIRI) chemotherapy in adults with metastatic colorectal cancer (mCRC) that is resistant to or has progressed after an oxaliplatin-containing regimen.

The European Commission now needs to ratify the positive opinion from CHMP to grant marketing authorization of ZALTRAP in all 27 European Union member

countries. A decision is expected from the European Commission in the first quarter of 2013. The CHMP opinion was based on data from the pivotal VELOUR trial.

We are pleased that CHMP has supported our ZALTRAP application. This brings us one step closer to bringing this novel treatment with a proven survival benefit to colorectal cancer patients in

Europe, said Debasish Roychowdhury, M.D., Senior Vice President and Head, Sanofi Oncology.

It is gratifying to see the

years of effort that went into designing and developing the angiogenesis inhibitor ZALTRAP translate into a clinical benefit for patients with metastatic colorectal cancer that has progressed on prior therapy, said George D. Yancopoulos,

M.D., Ph.D., Chief Scientific Officer of Regeneron and President of Regeneron Laboratories. ZALTRAP is the only agent that has demonstrated a statistically significant improvement in overall survival in combination with FOLFIRI versus

FOLFIRI alone in patients who progressed on a prior oxaliplatin-containing regimen.

ZALTRAP received approval from the U.S. Food

and Drug Administration (FDA) in August 2012, and marketing authorization applications for ZALTRAP are under review with other regulatory agencies worldwide.

About the VELOUR Phase III Study

The VELOUR trial was a Phase III multinational,

randomized, double-blind trial comparing FOLFIRI in combination with either ZALTRAP or placebo in the treatment of patients with mCRC. The study randomized 1,226 patients with mCRC who previously had been treated with an oxaliplatin-containing

regimen. Twenty-eight percent of patients in the study received prior bevacizumab therapy. The primary endpoint was overall survival. Secondary endpoints included progression-free survival, overall response rate, and safety

The VELOUR trial showed that in patients previously treated with an oxaliplatin-containing regimen, adding ZALTRAP to FOLFIRI significantly improved

median survival from 12.06 months to 13.50 months (HR=0.817 [95% CI 0.714 to 0.935]; p=0.0032, an 18 percent relative risk reduction. A

significant improvement in progression-free survival from 4.67 months to 6.90 months (HR=0.758 [95% CI 0.661 to 0.869]; p=0.00007), a 24 percent relative risk reduction, was also observed. The

overall response rate in the ZALTRAP plus FOLFIRI arm was 19.8% vs. 11.1% for FOLFIRI (p=0.0001).

The most common adverse reactions (all

grades, greater than or equal to 20% incidence) reported at a higher incidence (2% or greater between-arm difference) in the ZALTRAP-FOLFIRI arm, in order of decreasing frequency, were leucopenia, diarrhea, neutropenia, proteinuria, AST increased,

stomatitis, fatigue, thrombocytopenia, ALT increased, hypertension, weight decreased, decreased appetite, epistaxis, abdominal pain, dysphonia, serum creatinine increased, and headache. The most common Grade 3-4 adverse reactions (greater than or

equal to 5%) reported at a higher incidence (2% or greater between-arm difference) in the ZALTRAP-FOLFIRI arm, in order of decreasing frequency, were neutropenia, diarrhea, hypertension, leucopenia, stomatitis, fatigue, proteinuria, and asthenia.

About ZALTRAP (aflibercept)

ZALTRAP is recombinant fusion protein

that binds the angiogenic proteins Vascular Endothelial Growth Factor-A (VEGF-A), VEGF-B and placental growth factor (PIGF). VEGF-A is one of the mediators contributing to angiogenesis. VEGF-B and PlGF, related growth factors in the VEGF family, may

contribute to tumor angiogenesis as well. In the U.S., ZALTRAP is a registered trademark of Regeneron Pharmaceuticals, Inc.

ZALTRAP is approved with the U.S. proper name ziv-aflibercept for use in combination with FOLFIRI, in patients with metastatic colorectal cancer (mCRC) that is resistant to or has progressed following an oxaliplatin-containing regimen. The World

Health Organization (WHO) recommended international non-proprietary name for ZALTRAP is aflibercept.

About Colorectal Cancer

Worldwide, colorectal cancer is the third most commonly diagnosed cancer in males and the second most in females, with more than

1.2 million new cases diagnosed in 2008. One of the deadliest cancers, colorectal cancer was responsible for more than 600,000 deaths globally in 2008 alone. According to the American Cancer Society, approximately 60 percent of colorectal

cancer cases are diagnosed at the locally advanced or metastatic stage. Although survival for early stage disease is relatively high, once colorectal cancer metastasizes to distant organs, five-year survival is estimated to be 12

About Sanofi Oncology

Based in Cambridge, Massachusetts, USA and Vitry, France, Sanofi Oncology is dedicated to translating science into effective therapeutics that address

unmet medical needs for cancer and organ transplant patients. Starting with a deep understanding of the disease and the patient, Sanofi Oncology employs innovative approaches to drug discovery and clinical development, with the ultimate goal of

bringing the right medicines to the right patients to help them live healthier and longer lives. We believe in the value of partnerships that combine our internal scientific expertise with that of industry and academic experts. Our portfolio

includes 11 marketed products and more than 15 investigational compounds in clinical development, including small molecules and biological agents.

Sanofi, a global and diversified healthcare leader, discovers, develops and

distributes therapeutic solutions focused on patients needs. Sanofi has core strengths in the field of healthcare with seven growth platforms: diabetes solutions, human vaccines, innovative drugs, consumer healthcare, emerging markets, animal

health and the new Genzyme. Sanofi is listed in Paris (EURONEXT: SAN) and in New York (NYSE: SNY).

About Regeneron Pharmaceuticals, Inc.

Regeneron is a fully integrated biopharmaceutical company that discovers, invents, develops, manufactures, and commercializes

medicines for the treatment of serious medical conditions. Regeneron markets three products in the United States,

EYLEA (aflibercept) Injection, ZALTRAP (ziv-aflibercept) Injection for Intravenous Infusion, and ARCALYST (rilonacept) Injection for Subcutaneous Use; ZALTRAP is co-commercialized with Sanofi. Phase 3 studies are in progress with EYLEA in two additional indications and

with product candidates sarilumab and REGN727. Regeneron has active research and development programs in many disease areas, including ophthalmology, inflammation, cancer, and hypercholesterolemia. Additional information and recent news releases are

available on the Regeneron web site at www.regeneron.com.

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and analysis, including post marketing, decisions by regulatory authorities, such as the FDA or the EMA, regarding whether and when to approve any drug, device or biological application that may be filed for any such product candidates as well as

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Regeneron Forward-Looking Statements

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future performance of Regeneron, and actual events or results may differ materially from these forward-looking statements. These statements concern, and these risks and uncertainties include, among others, the nature, timing, and possible success

and therapeutic applications of Regeneron s products, product candidates and research and clinical programs now underway or planned, including without limitation ZALTRAP (ziv-aflibercept), unforeseen safety issues resulting from the administration of products and product candidates in patients, the likelihood and timing of possible

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with third party intellectual property and pending or future litigation relating thereto. 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, including its Form 10-K for the year ended December 31, 2011 and its Form 10-Q for the quarter ended September 30, 2012. Regeneron does not undertake any obligation to update publicly any forward-looking statement, whether as a

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