Data at ASCO Showcase Sanofi’s Commitment to Research and Identify Treatments for Cancer Patients

Iniparib and Semuloparin Phase III Data Selected for Oral Presentation and Best of ASCO

Paris, France – May 19, 2011 – Sanofi (EURONEXT: SAN and NYSE: SNY) today announced that data from eight compounds in the company’s robust oncology portfolio will be showcased in more than 100 abstracts at the 47th Annual Meeting of the American Society of Clinical Oncology (ASCO) in Chicago, June 3-7, 2011.

Data presentations highlight the Sanofi Oncology pipeline in both solid tumors and hematologic malignancies. New research from early through late stage development will be reported, including data on cabazitaxel, docetaxel and oxaliplatin, as well as on investigational compounds iniparib and semuloparin.

“Sanofi fully supports this year’s ASCO Presidential Theme - Patients, Pathways and Progress. Our connection to the patient inspires us to partner with leading experts to exchange ideas that will help us discover innovative solutions to improve patient outcomes,” said Debasish Roychowdhury, MD, Senior Vice President and Head of Global Oncology Division. “Sanofi is committed to ASCO and its mission.”

Abstract titles of presentations selected for Best of ASCO include:
The 2011 Best of ASCO Meetings feature the most relevant and cutting-edge science in oncology
research.

• Abstract #1007: Monday, June 6, 2011, 11:00-11:15am CDT: A Randomized Phase III Study of Iniparib (BSI-201) in combination with Gemcitabine (G) and Carboplatin (C) in Metastatic Triple Negative Breast Cancer (mTNBC).
  - Joyce O’Shaughnessy, MD, Baylor-Charles A. Sammons Cancer Center
  - Breast Cancer – Triple-negative/Cytotoxics/Local Therapy Oral Abstract Session, Hall B1.
• Abstract #LBA9014: Monday, June 6, 2011, 2:45-3:00pm CDT: The ultra-low-molecular-weight heparin (ULMWH) Semuloparin for Prevention of Venous Thromboembolism (VTE) in Cancer Patients Receiving Chemotherapy: SAVE ONCO Study.
  - Giancarlo Agnelli, MD, University of Perugia, Italy
  - Patient and Survivor Care Oral Abstract Session, S404.

Abstract titles of other notable data accepted for presentation at the ASCO meeting include:

• Abstract #5004: Saturday, June 4, 2011, 3:15-3:30pm CDT: A Phase II Trial of Iniparib (BSI-201) in combination with Gemcitabine/Carboplatin (GC), in Patients with Platinum-Sensitive Recurrent Ovarian Cancer.
  - Richard T. Penson, MD, MRCP, Massachusetts General Hospital
  - Gynecological Cancer Oral Abstract Session, E354a.
• Abstract #5005: Saturday, June 4, 2011, 3:30-3:45pm CDT: A Phase II Trial of Iniparib (BSI-201) in combination with Gemcitabine/Carboplatin (GC), in Patients with Platinum-Resistant Recurrent Ovarian Cancer.
  - Michael J. Birrer, MD, PhD, Massachusetts General Hospital
  - Gynecological Cancer Oral Abstract Session, E354a.
• Abstract #4525: Saturday, June 4, 2011, 2:00-6:00pm: Survival Benefit from First Docetaxel Treatment for Cabazitaxel plus Prednisone Compared with Mitoxantrone plus Prednisone in Patients with Metastatic Castration-resistant Prostate Cancer (mCRPC) Enrolled in the TROPIC Trial.
  - A. Oliver Sartor, MD, Tulane School of Medicine
  - Genitourinary Cancer Poster Discussion Session, E450a, Poster #5.
• Abstract #4526: Saturday, June 4, 2011, 2:00-6:00pm CDT: A Subgroup Analysis of the TROPIC Trial Exploring Reason for Discontinuation of Prior Docetaxel and Survival Outcome of Cabazitaxel in Metastatic Castration-resistant Prostate Cancer (mCRPC).
  - Johann Sebastian De Bono MD, The Royal Marsden Hospital, UK
  - Genitourinary Cancer Poster Discussion Session, E450a, Poster #6.

About Iniparib (BSI-201)
BSI-201 is a novel investigational oncology agent that is in Phase III trials for patients with squamous non-small cell lung cancer, as well as in Phase II trials for patients with breast, lung and other cancers. Iniparib is the United States Adopted Name (USAN) for BSI-201.

About Cabazitaxel
Cabazitaxel is a semi-synthetic taxane and works differently than docetaxel and paclitaxel. An antineoplastic agent, it acts by disrupting the microtubular network in cells. It binds to tubulin and promotes the assembly of tubulin into microtubules while simultaneously inhibiting their disassembly. This leads to the stabilization of microtubules. Cabazitaxel demonstrated a broad spectrum of antitumor activity against advanced solid tumours xenografted in mice. Cabazitaxel is active in docetaxel sensitive tumors. In addition, cabazitaxel demonstrated activity in tumour models insensitive to chemotherapy, including docetaxel.

About Semuloparin
Semuloparin is an investigational, selectively engineered anticoagulant that belongs to the ultra- lowmolecular-weight heparin (ULMWH) class. Semuloparin has a novel anti-thrombotic profile resulting from an enriched antithrombin binding site and high-activity against factor Xa and residual activity
against factor IIa. A large phase III clinical study (SAVE ONCO study) investigated semuloparin in cancer patients receiving chemotherapy that has been completed. The SAVE ONCO study assessed the efficacy and safety of semuloparin for the prevention of symptomatic VTE, Pulmonary Embolism and VTE related death in cancer patients receiving chemotherapy. There is currently no product registered in this  indication.

About BiPar Sciences
BiPar Sciences is a biopharmaceutical organization dedicated to pioneering novel tumor-selective
therapies designed to address urgent unmet needs of cancer patients. Located in South San
Francisco, California, BiPar is a wholly owned subsidiary of Sanofi. For more information, please
visit www.biparsciences.com.

About Sanofi Oncology
Based in Cambridge, Massachusetts, and Vitry, France, Sanofi Oncology is translating science into effective cancer therapeutics to address unmet medical needs for patients with cancer. Starting with a deep understanding of the mechanisms by which cancer develops, grows and spreads, the company employs innovative approaches in drug discovery, clinical development and partnerships to bring the right medicines to the right patients with the goal of helping cancer patients live healthier and longer lives.

Sanofi Oncology is committed to the pursuit of science and innovative cancer therapies. We believe in partnership with leading experts, and combining that expertise with our own internal scientific strength and heritage. There are currently more than 10 compounds in clinical development including small  molecules and biological agents.

Contacts:
Oncology Division Communications
Lauren Musto
Tel: 1 (617) 665-4618
E-mail: lauren.musto@sanofi.com

Corporate Media Relations
Marisol Peron
Tel: +33 (0) 1 53 77 45 02
Mobile: +33 (0) 6 08 18 94 78
E-mail: marisol.peron@sanofi.com

Investor Relations
Sébastien Martel
Tel.: + (33) 1 53 77 45 45
E-mail: ir@sanofi.com