Sanofi Pasteur's Dengue Vaccine in Final Stage of Clinical Development

Lyon, France, November 4 (ots/PRNewswire) - Sanofi Pasteur, the
vaccines division of sanofi-aventis Group , announced today that its
dengue vaccine is in final stage of clinical development. Sanofi
Pasteur's dengue vaccine, the world's most clinically advanced dengue
vaccine candidate(1,2), entered its first phase 3 clinical study in
Australia.

This study is part of a global phase 3 clinical study program
aimed at advancing the development of a novel vaccine for the
prevention of dengue disease in children and adults. Currently, there
is no specific treatment available for dengue fever, which is a
threat to nearly three billion people and a public health priority in
many countries of Latin America and Asia where epidemics occur.(3)

Phase 3 studies are the ultimate steps in the clinical
development of a vaccine before it is submitted to regulatory
authorities for evaluation for market authorization. Sanofi Pasteur's
candidate dengue vaccine is the first to reach phase 3 of clinical
development.

"To address the global health challenge represented by dengue
fever, we are conducting an unprecedented dengue vaccine research and
development program as well as a scale up of the vaccine production,"
said Wayne Pisano, President and Chief Executive Officer of Sanofi
Pasteur. "We are now entering the final laps of a long run that
Sanofi Pasteur started almost 20 years ago. If successful, we are
committed to introducing the vaccine in countries where dengue is of
highest public health priority."

The study in Australia is the first to use dengue vaccine doses
produced with industrial scale processes. The study is aimed at
demonstrating that production of the vaccine at industrial scale will
meet consistency criteria required for market authorization by
regulatory authorities. Details of the phase 3 study in Australia as
well as results of already completed studies are presented at the
59th annual conference of ASTMH (American Society of Tropical
Medicine and Hygiene), held in Atlanta (Georgia, United States),
November 3-7.

Sanofi Pasteur's global dengue vaccine clinical study program

Sanofi Pasteur's candidate dengue vaccine-which targets all four
virus serotypes-has been evaluated in clinical studies (Phase 1, 2)
in adults and children in the U.S., Asia and Latin America. Overall,
a balanced immune response against all four serotypes was observed
after three doses of the vaccine. The vaccine is well tolerated with
a similar safety profile after each dose.(4)

Clinical studies in adults and children are ongoing in Mexico,
Colombia, Honduras, Puerto Rico, Peru, the Philippines, Vietnam,
Singapore, Australia, and Thailand.

About dengue fever

Dengue fever is a mosquito-borne disease caused by four dengue
virus serotypes (1 to 4). Overall, the disease is a potential threat
to almost half of the world's population. Of the estimated 220
million people infected annually, two million-mostly children-develop
dengue hemorrhagic fever (DHF), a severe form of the disease.(5) DHF
is a leading cause of hospitalization, placing tremendous pressure on
strained medical resources and having a heavy economic and societal
impact. Many factors have contributed to the re-emergence and
dramatic increase in dengue fever including urbanization and
increased travel which facilitates dissemination of dengue viruses
and the circulation of all four dengue virus serotypes.

For continuous up to date information about dengue fever
outbreaks, visit http://www.denguewatch.org, a news hub reporting
worldwide alerts on dengue, provided by the Pediatric Dengue Vaccine
Initiative.

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 and in New
York . 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

1. Dengue vaccine efficacy trials in progress,
http://www.thelancet.com/infection, vol 9, November 2009

2. Jean Lang, Recent progress on Sanofi Pasteur's dengue vaccine
candidate. Journal of Clinical Virology 46, S2 (2009) 20-24

3. WHO Fact sheet No117, March 2009 Dengue and dengue
haemorrhagic fever

4. Saville et al, Clinical development of a tetravalent dengue
vaccine for endemic areas, ICID Miami, March 2010; Lang et al,
Toward a tetravalent dengue vaccine in Brazil, Tropical Medicine
meeting, Iguacu Falls, March 2010

5. PDVI Newsletter No 7, April 2010 accessible at
http://www.pdvi.org/PDVI_newsletter/newsletter.asp

Forward Looking Statements

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in the Private Securities Litigation Reform Act of 1995, as amended.
Forward-looking statements are statements that are not historical
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differ materially from those expressed in, or implied or projected
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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.

http://www.sanofipasteur.us

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ots Originaltext: sanofi-aventis Group
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Contact:
CONTACT: Contacts: Global Media Relations, Pascal Barollier,
T.+33-(0)4-37-37-50-38, pascal.barollier@sanofipasteur.com; US
MediaRelations, Len Lavenda, T.
+1-570-957-0717len.lavenda@sanofipasteur.com