Sanofi Pasteur Starts a Phase II Vaccine Trial for Primary Prevention of Clostridium Difficile

Vaccine Against one of the Most Common Causes of Hospital-acquired Infection in North America & Europe Tested in the U.S.

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Sanofi Pasteur

Nov 29, 2010, 09:00 ET

SWIFTWATER, Pennsylvania, November 29, 2010 /PRNewswire-FirstCall/ -- Sanofi Pasteur, the vaccines division of sanofi-aventis Group, announced today that it has started its phase II clinical study of a vaccine for primary prevention of Clostridium difficile infection (CDI). The trial starting in the United States is focused on evaluating prevention of the first episode of CDI in at-risk individuals, which includes adults with imminent hospitalization or current or impending residence in a long-term care or rehabilitation facility.

The incidence of CDI has increased significantly in recent years in both North America and Europe. CDI-related treatments in these two regions of the world are estimated to be costing more than $7 billion a year. The recent emergence and spread of a hyper-virulent strain of C. difficile further highlights the importance of preventing CDI.

C. difficile is present worldwide and has become the most frequent hospital-acquired infection in the U.S., Europe, and Canada. Standard treatment of C. difficile infection involves the use of antibiotics. The Sanofi Pasteur trial is investigating the safety and immunogenicity of different formulations of a Clostridium difficile toxoid vaccine administered in adults aged 40 to 75 years who are at risk of C. difficile infection.

"Sanofi Pasteur has chosen a well established approach for this particular vaccine. Toxoids have been used as the basis of a number of highly successful vaccines," explained Michel DeWilde, PhD, Senior Vice President for R&D at Sanofi Pasteur."This candidate vaccine has completed phase I clinical trials in more than 200 participants to evaluate its safety and immunogenicity."

The U.S. Food and Drug Administration (FDA) recently granted fast-track designation to Sanofi Pasteur's investigational Clostridium difficile vaccine candidate. The fast-track program of the FDA is designed to facilitate the development and expedite the review of new drugs and vaccines that are intended to treat or prevent serious or life-threatening conditions and demonstrate the potential to address unmet medical needs.

The phase II trial hopes to recruit approximately 650 participants at some 30 health-care centers across the U.S. For more information on the trial and the sites conducting the study, go to http://www.Clintrials.gov.

About C. difficile

C. difficile is an anaerobic spore-forming bacterium, present asymptomatically in approximately 60 percent of infants and approximately three percent of healthy adults. It belongs to the Clostridium family of bacteria, which also includes C. tetani (tetanus) and C. botulinum (botulism). The C. difficile bacteria produce two potent toxins: A and B. When the natural microbial flora of the gut is disturbed, usually as a result of antibiotic treatment for other illnesses, and a patient is exposed to C. difficile spores, the bacteria can multiply and release the two toxins, which cause a broad range of gastrointestinal symptoms in humans known collectively as CDI.

Hospital-acquired infections caused by C. difficile are a considerable problem in many industrialized countries, including the U.S., Canada, and Europe. It is estimated that there are about 500,000 cases of CDI in the US alone[1], with annual costs to the healthcare system of $3.2 billion[2]. In the EU, assuming a population of about 460 million people, the healthcare costs of CDI are estimated to be around $4.4 billion per year.[3] Additional information is available at the US Centers for Disease Control and Prevention and UK Health Protection Agency C. difficile information pages[1],[4].

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: SAN) and in New York (NYSE: SNY). For more information, please visit: http://www.sanofi-aventis.com

Sanofi Pasteur, the vaccines division of sanofi-aventis Group, provided more than 1.6 billion doses of vaccine in 2009, making it possible to immunize more than 500 million people across the globe. A world leader in the vaccine industry, Sanofi Pasteur offers the broadest range of vaccines protecting against 20 infectious diseases. The company's heritage, to create vaccines that protect life, dates back more than a century. Sanofi Pasteur is the largest company entirely dedicated to vaccines. Every day, the company invests more than EUR 1 million in research and development. For more information, please visit: http://www.sanofipasteur.com or http://www.sanofipasteur.us

References:

1. CDC: http://www.cdc.gov/ncidod/dhqp/id_Cdiff.html

2. O'Brien et al, The Emerging Infectious Challenge of Clostridium difficile-Associated Disease in Massachusetts Hospitals: Clinical and Economic Consequences. Infection Control and Hospital Epidemiology, 2007; 28(11):1219-1227

3. European Centre for Disease Prevention and Control, Emergence of Clostridium difficile-associated disease in North America and Europe, Clinical Microbiology and Infectious Diseases, 2006; 12 (Suppl. 6): 2-18

    4. HPA:
http://www.hpa.nhs.uk/webw/HPAweb&Page&HPAwebAutoListName/Page/1179744911867

Forward Looking Statements

This press release contains forward-looking statements as defined in the Private Securities Litigation Reform Act of 1995, as amended. Forward-looking statements are statements that are not historical facts. These statements include projections and estimates and their underlying assumptions, statements regarding plans, objectives, intentions and expectations with respect to future financial results, events, operations, services, product development and potential, and statements regarding future performance. Forward-looking statements are generally identified by the words "expects," "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 among other things, the uncertainties inherent in research and development, future clinical data 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 their decisions regarding labelling and other matters that could affect the availability or commercial potential of such products candidates, the absence of guarantee that the products candidates if approved will be commercially successful, the future approval and commercial success of therapeutic alternatives, the Group's ability to benefit from external growth opportunities as well as 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, 2009. Other than as required by applicable law, sanofi-aventis does not undertake any obligation to update or revise any forward-looking information or statements.

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