Sanofi and DNDi - Drugs for Neglected Diseases initiative - Sign an Innovative Agreement to Generate New Drugs for Neglected Tropical Diseases

PARIS and GENEVA, June 2, 2011 -

Sanofi (EURONEXT: SAN and NYSE:SNY) and Drugs for Neglected
Diseases initiative (DNDi) announced today a three-year research
collaboration agreement for the research of new treatments for nine neglected
tropical diseases (NTDs), listed by the World Health Organization (WHO) for
which new, adapted, and efficient tools are urgently needed to treat patients
in endemic countries. This agreement is built upon a history of successful
collaboration between Sanofi and DNDi.

In the framework of this agreement, Sanofi will initially
bring molecules from its libraries into the partnership, while DNDi and
Sanofi collaborate in research activities on innovative molecular scaffolds.
The core of the agreement lies in the innovative management of intellectual
property generated through the collaboration. The rights to results produced
by this partnership will be co-owned by Sanofi and DNDi. The partners will
facilitate publication of the results to ensure access to the wider community
of researchers focusing on NTDs. The public sector will benefit from the
drugs developed through this agreement under the best possible conditions to
ease access for patients in all endemic countries, irrespective of their
level of economic development.

"Sanofi is committed to bringing therapeutic solutions to
those most affected and exposed to neglected tropical diseases (NTDs)," said
Dr. Elias Zerhouni, President, Global Research & Development, Sanofi. "In
this new research collaboration with DNDi, we have taken a firm step towards
greater flexibility in the sharing of knowledge to produce new medicines."

"This agreement is a major milestone in our access to
molecules that can help combat neglected diseases," said Dr. Bernard Pécoul,
Executive Director of DNDi. "We believe that this level of private-sector
involvement in open-research collaboration to deliver appropriate medicines
as public goods is vital to addressing the needs of the most vulnerable
populations of the world. The agreement allows DNDi to continue making
science work more efficiently for the patients who need it most. We encourage
and commend such engagement."

Neglected Tropical Diseases covered by the agreement

This agreement covers nine neglected tropical diseases (NTDs):
kinetoplastid diseases (leishmaniass, Chagas disease, and human African
trypanosomiasis), helminth infections (lymphatic filariasis, onchocerciasis,
and soil-transmitted helminthiasis), and dracunculiasis, fascioliasis, and
schistosomiasis.

Sanofi's involvement in neglected disease

Sanofi has been involved in the field of NTDs since the 1940s,
through research programmes and manufacturing of treatments for sleeping
sickness and leishmaniasis. In 2001, Sanofi entered into a partnership
agreement with WHO to fight sleeping sickness. In 2006, this partnership was
expanded to include leishmaniass, Buruli ulcer, and Chagas disease and
renewed for a further 5 years in 2011. To improve existing drugs and
anticipate tomorrow's challenges, Sanofi created in 2010, within its Research
& Development organization, a Therapeutic Strategic Unit dedicated to new
anti-infectives. Its scope includes multiresistant bacterial infections as
well as some NTDs.

About Sanofi

Sanofi, a global and diversified healthcare leader, discovers,
develops and distributes therapeutic solutions focused on patients' needs.
Sanofi has core strengths in the field of healthcare with seven growth
platforms: diabetes solutions, human vaccines, innovative drugs, rare
diseases, consumer healthcare, emerging markets and animal health. Sanofi is
listed in Paris (EURONEXT: SAN) and in New York (NYSE: SNY).

About Drugs for Neglected Diseases initiative (DNDi)

DNDi is a not-for-profit product development partnership
working to research and develop new treatments for neglected diseases, in
particular human African trypanosomiasis, leishmaniasis, Chagas disease,
malaria, paediatric HIV, and specific helminth-related infections. DNDi was
established in 2003 by the Oswaldo Cruz Foundation from Brazil, the Indian
Council for Medical Research, the Kenya Medical Research Institute, the
Ministry of Health of Malaysia, Pasteur Institute, and Médecins sans
Frontières (MSF). WHO/TDR acts as a permanent observer. Since 2007, DNDi has
delivered four products: two fixed-dose anti-malarials (ASAQ developed with
Sanofi and ASMQ), NECT (nifurtimox-eflornithine combination therapy for
sleeping sickness), and SSG&PM, a combination therapy to treat visceral
leishmaniasis in Africa. For more information, www.dndi.org

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
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similar expressions. Although Sanofi's management believes that the
expectations reflected in such forward-looking statements are reasonable,
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predict and generally beyond the control of Sanofi, 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 labeling 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, including those listed under "Risk
Factors" and "Cautionary Statement Regarding Forward-Looking Statements" in
Sanofi's annual report on Form 20-F for the year ended December 31, 2010.
Other than as required by applicable law, Sanofi does not undertake any
obligation to update or revise any forward-looking information or statements.

Contacts: Sanofi Corporate Media Relations, Marisol Peron, Tel: +33(0)1-53-77-46-46, marisol.peron at sanofi.com; DNDi, Violaine Dällenbach, Tel: +41(0)22-906-92-47, vdallenbach at dndi.org