Sanofi Pasteur Dengue Vaccine Enters Pediatric Efficacy Clinical Study

Lyon, France (ots/PRNewswire) -

- Global Clinical Study Program Across Dengue Endemic Regions in
Latin America and Asia

Sanofi Pasteur, the vaccines division of sanofi-aventis Group
(EURONEXT : SAN and NYSE : SNY), announced today that its
investigational tetravalent dengue vaccine is entering into a
pediatric clinical study in Thailand to assess the efficacy of the
vaccine in protecting children against dengue, the most widespread
tropical disease after malaria. Sanofi Pasteur's tetravalent dengue
vaccine candidate is the first to reach this stage of clinical
development.

Sanofi Pasteur is collaborating with Mahidol University of
Thailand, the Ministry of Public Health, and the Pediatric Dengue
Vaccine Initiative (PDVI) to conduct this efficacy study in the
province of Ratchaburi.

"Large scale pediatric studies are instrumental for the
development of a safe and efficacious dengue vaccine to protect
against a disease that primarily affects children," said Dr. Pratap
Singhasivanon, Dean of the Faculty of Tropical Medicine, Mahidol
University. "We are happy to contribute to an important milestone
with the actual start of an efficacy study in Ratchaburi."

The Sanofi Pasteur clinical study program follows guidelines from
the Initiative for Vaccine Research (IVR) led by the World Health
Organization (WHO), which fosters the global efforts towards dengue
vaccine development.

"WHO is committed to the availability of a dengue vaccine that
will ultimately benefit children in endemic countries," said Dr.
Joachim Hombach, Coordinator Implementation Research for IVR, WHO.

About Sanofi Pasteur dengue vaccine global clinical study
program

Sanofi Pasteur started the development of a dengue vaccine in the
90's. Clinical studies with the most advanced tetravalent candidate
vaccine started in the 2000's. In a study in the United States,
immunization with three doses of Sanofi Pasteur's tetravalent dengue
vaccine candidate generated a sero-neutralizing antibody response
against all four serotypes of the virus responsible for dengue fever
in 100 percent of adults who participated in the trial(1). The Sanofi
Pasteur dengue vaccine research program includes ongoing clinical
studies in Mexico, Peru, and The Philippines with adults and
children.

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: http://www.sanofipasteur.com

References:

1. Data generated by the WHO Flavivirus Laboratory Reference
Center, Mahidol University, Bangkok, Thailand, presented at the
American Society of Tropical Medicine and Hygiene's (ASTMH) 56th
annual meeting held in Philadelphia, Pennsylvania, USA

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,
http://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 product development, product
potential 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 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 EMEA, 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 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, 2007. Other than as required by
applicable law, sanofi-aventis does not undertake any obligation to
update or revise any forward-looking information or statements.

http://www.sanofipasteur.com

http://www.sanofipasteur.us

ots Originaltext: sanofi-aventis Group
Im Internet recherchierbar: http://www.presseportal.de

Contact:
Contacts : Global Media Relations, Pascal Barollier, T.
+33(0)4-37-37-50-38, pascal.barollier@sanofipasteur.com; US Media
Relations: Len Lavenda, T. +1-570-957-4446,
len.lavenda@sanofipasteur.com