Sanofi Pasteur Global Dengue Vaccine Clinical Program Expanded to Singapore and Vietnam

SINGAPORE - New Studies Advance the Development of Novel Vaccine for Dengue Prevention in Asia Pacific

SINGAPORE, April 21 /PRNewswire/ –

Sanofi Pasteur, the vaccines division of sanofi-aventis Group (EURONEXT : SAN and NYSE : SNY), announced today the start of clinical studies of its investigational tetravalent dengue vaccine in Singapore and Vietnam.

With these studies, sanofi pasteur is expanding its global dengue vaccine clinical study program in Asia where trials are already ongoing in Thailand and the Philippines. These studies are aimed at advancing the development of a novel vaccine for the prevention of dengue in the Asia-Pacific region.

“Dengue has emerged as a serious public health problem in Asia-Pacific in the last decades. There are 1.8 billion people in the region at risk of dengue fever,” said Chusak Prasittisuk, Coordinator Communicable Diseases Control at the World Health Organization South East- Asia Region. “WHO is committed to fostering vaccine development for the control of dengue disease in Asia.”

Currently, there is no specific treatment available against dengue fever, which is the most widespread tropical disease after malaria. Sanofi Pasteur is collaborating with the Communicable Disease Center in Singapore and the Pasteur Institute in Vietnam to conduct these clinical studies in children and adults.

“Controlling the mosquitoes that transmit dengue is necessary but not sufficient to fight against the disease. A safe and effective vaccine has been long awaited to prevent dengue epidemics,” said Professor Leo Yee Sin, director of the Communicable Disease Center in Singapore. “Clinical studies in Singapore are critical steps to advance the development of a vaccine for the prevention of dengue in Asia. We are happy to contribute to scientific research that would benefit the entire region.”

“Fighting against dengue is a main public health priority in Vietnam. About 100,000 people are infected each year, mostly children,” said Dr. Tran Ngoc Huu, director of Pasteur Institute in Ho Chi Minh City. “The Pasteur Institute is committed to supporting clinical studies for a dengue vaccine that would ultimately benefit children in Vietnam.”

A global clinical study program across endemic regions in Asia and Latin America

Sanofi Pasteur started the development of a dengue vaccine in the ’90s. Clinical studies with the most advanced tetravalent candidate vaccine started in the 2000s. Sanofi Pasteur tetravalent dengue vaccine candidate has been evaluated in clinical trials in adults and children from non-endemic and endemic countries (U.S., Mexico, Philippines). Overall, a balanced immune response against all four serotypes was observed after three doses of the vaccine. The vaccine appears to be well tolerated with a similar safety profile after each dose(1). Sanofi Pasteur’s dengue vaccine research program includes ongoing clinical studies in Mexico, Peru, The Philippines and Thailand, with adults and children. The goal of the pediatric clinical study in Thailand is to assess the efficacy of the vaccine in protecting children against symptomatic dengue infection. Sanofi Pasteur’s tetravalent dengue vaccine candidate is the first to reach this stage of clinical development.

About dengue fever

Dengue fever is a mosquito-borne disease caused by four types of dengue viruses (type 1 to 4). Overall, the disease is a potential threat for almost half the world’s population. Of the estimated 230 million people infected annually, two million, mostly children, develop dengue hemorrhagic fever (DHF), a severe form of the disease(2). DHF is a leading cause of hospitalization in South-East Asia, placing tremendous pressure on strained medical resources.

Dengue fever occurs mostly in tropical and subtropical countries and is spreading to new parts of the globe each year. The WHO has warned that the Western Pacific Region may be heading for a major dengue outbreak(3). Outbreaks recently have been observed in Paraguay and the Middle East. In addition, dengue affects countries such as Australia (Queensland) and the United States (Puerto Rico, Texas-Mexico border, Hawaii and the US-affiliated Pacific Islands). A substantial number of people traveling to endemic regions are also infected each year.

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).

Sanofi Pasteur, the vaccines division of sanofi-aventis Group, provided more than 1.6 billion doses of vaccine in 2008, 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: www.sanofipasteur.com or www.sanofipasteur.us.

References:

1. Bouckenooghe et al presented at 57th ASTMH annual meeting, New Orleans, December 2008

2. Pediatric Dengue Vaccine Initiative (PDVI), presentation “Estimating the global burden of dengue” at 2nd Int Conf on Dengue & DHF, 15-17 Oct 08 , Phuket, Thailand

3. WHO alarmed about the spread of dengue, www.wpro.who.int/media_centre/press_releases/pr_23072007.htm

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 financial projections and estimates and their underlying assumptions, statements regarding plans, objectives, intentions and expectations with respect to future events, operations, products and services, 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 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 sanofiaventis’ annual report on Form 20-F for the year ended December 31, 2008. Other than as required by applicable law, sanofi-aventis does not undertake any obligation to update or revise any forward-looking information or statements.

www.sanofipasteur.com

www.sanofipasteur.us

SINGAPORE, April 21 /PRNewswire/ –

Source: Sanofi Pasteur

Contacts: Global Media Relations: Pascal Barollier, T. +33-(0)4-37-37-50-38, pascal.barollier at sanofipasteur.com; US Media Relations: Len Lavenda, T. +1-570-957-0717, len.lavenda at sanofipasteur.com.