Investigational Oral Multiple Sclerosis Therapy Teriflunomide (Aubagio?(*)) Significantly Reduced Relapse Rate, Disability Progression and Disease Activity

Paris (ots/PRNewswire) -

- Findings from Two-Year Pivotal Phase III TEMSO Trial Published
today in The New England Journal of Medicine -

Sanofi and its subsidiary Genzyme announced today the
publication of the pivotal Phase III TEMSO study with investigational
once-daily oral medication teriflunomide in The New England Journal
of Medicine (NEJM). Results showed that teriflunomide at the 14mg
dosage significantly reduced the annual relapse rate, reduced
disability progressions and improved several magnetic resonance
imaging (MRI) measures of disease activity, including new or
worsening brain lesions. Teriflunomide has a well-characterized
safety profile, with a similar proportion of trial participants
reporting adverse events compared to placebo.

"The TEMSO data demonstrate the effect of teriflunomide in terms
of reducing relapse rates, disability progression and Magnetic
Resonance Imaging (MRI) lesions," said Dr. Paul O'Connor, Director of
the MS Clinic at St Michael's Hospital, Toronto, Canada and principal
investigator in the TEMSO study. "These results, sustained over two
years, provide clinically meaningfuldata for teriflunomide."

The two-year TEMSO (TEriflunomide Multiple Sclerosis Oral) trial
involved 1,088 people with relapsing forms of MS from 126 centers
across 21 countries. TEMSO is the first study from a broad clinical
development program that includes more than 4,000 trial participants
in 36 countries and is one of the largest and broadest clinical
programs of any oral MS agent under development, with five Phase III
clinical trials either completed or underway.

"The publication of the teriflunomide results in the New England
Journal of Medicine is an exciting milestone as we continue the
development of our product," said Dr. Elias Zerhouni, President,
Global Research & Development, Sanofi. "As we continue our commitment
to research, innovation and the Multiple Sclerosis community, we look
forward to providing therapeutic options for patients across the
Multiple Sclerosis spectrum."

Teriflunomide has been filed with the FDA in August of 2011 and
the EMA filing is expected in the first quarter of 2012. The results
from the TEMSO study are and will be included in each regulatory
submission.

TEMSO findings showed that, compared to placebo, teriflunomide
once daily:

- Significantly reduced the risk of annual relapses, the
primary endpoint, by 31% (both p<0.001) for 7mg and 14mg doses.

- Significantly increased the time to first relapse, and
allowed significantly more trial participants to remain free of relapses
during the two years of the study: 53.7% (7mg, p=0.01 vs. placebo),
56.5% (14mg, p=0.003 vs. placebo) and 45.6% (placebo).

- The risk of 12-week confirmed disability progression, the
key secondary endpoint, was significantly reduced by 30% (p=0.03) for
the 14mg dose and numerically reduced by 24% (p=0.08) for the 7mg dose.

- Improved several standard magnetic resonance imaging (MRI)
measures of disease activity as compared to placebo including new or
worsening brain lesions with an apparent dose dependent effect in favor
of the 14mg dose:
- Reduced burden of disease (by 39.4% [p=0.03] and 67.4 %
[p<0.001] for 7mg and 14mg, respectively)
- Reduced gadolinium-enhancing T1 lesions (relative risk
reduction of 57% and 80%, p<0.001 for both doses);
- Reduced unique active lesions per scan (relative risk
reduction of 48% and 69%, p<0.001 for both doses).

Similar adverse events, serious adverse events, and adverse
events leading to treatment discontinuation were observed with
teriflunomide compared to placebo. No serious or opportunistic
infections and no deaths occurred in trial participants treated with
teriflunomide. The proportion of participants who discontinued the
study medication because of disease progression was significantly
smaller in the group receiving the 14mg of teriflunomide than in the
placebo group (p=0.02). Malignancies were reported in three
participants in the placebo group and one in the teriflunomide 14mg
group.

Teriflunomide adverse events were usually of mild to moderate
intensity, managed with existing therapies and rarely led to
treatment discontinuation. The most common were diarrhea, nausea,
liver enzyme increases (that were mainly mild and asymptomatic with
no dose effect) and mild hair thinning/decreased hair density. In
general, diarrhea, nausea and alopecia, were mild to moderate,
transient, and infrequently led to treatment discontinuation.

About Teriflunomide

Teriflunomide is an immunomodulatory, disease-modifying oral drug
with anti-inflammatory properties, and is under investigation for the
treatment of MS. Teriflunomide blocks the proliferation and
functioning of activated T and B lymphocytes - which are thought to
be especially damaging in MS - by selectively and reversibly
inhibiting a critical mitochondrial enzyme. Slowly dividing or
resting lymphocytes are unaffected by teriflunomide, leaving the
immune system's response to infection uncompromised. With nine years
of continuous use in a Phase II extension, teriflunomide has the
longest clinical experience of any investigational oral MS therapy.
In addition to the TEMSO trial, two other Phase III trials, TOWER and
TENERE, are ongoing in people with RMS. A Phase III study, TOPIC, is
also underway in early MS or CIS (clinically isolated syndrome).
Teriflunomide is also being evaluated as an adjunct therapy to
interferon-beta in the Phase III TERACLES trial.

(*) Aubagio(TM) is the registered name submitted to health
authorities for the investigational agent teriflunomide.

About Multiple Sclerosis

Today more than 2,000,000 people around the world suffer from MS,
a chronic autoimmune disease that affects the central nervous system
- the brain, spinal cord and optic nerves. In MS, immune cells called
lymphocytes mistakenly attack myelin, the fatty "insulation" that
surrounds and protects nerves, resulting in abnormal nerve
transmission and MS symptoms such as fatigue, weakness, walking and
balance problems, vision problems, pain, spasticity and cognitive
difficulties. MS is the most common disabling neurological disease in
young adults after accidents, and is two to three times more common
in women than in men. MS is usually characterized by relapses
followed by periods of complete or incomplete recovery. There is no
typical individual with MS, as the disease is a very variable
condition and the symptoms depend on which areas of the central
nervous system are affected. MS symptoms can vary from time to time
and can change in severity and duration, even in the same person.The
vast majority of people with MS - approximately 90 percent - are
initially diagnosed with a relapsing form of MS.

Magnetic resonance imaging (MRI) is a common and important tool
used to help establish a diagnosis of MS and monitor the course of
the disease and effects of treatment. Providing a highly sensitive,
non-invasive way to image the brain, spinal cord or, other areas of
the body, MRI has made it possible to visualize and understand a
great deal about the underlying pathology of MS.

About Genzyme, a Sanofi Company

One of the world's leading biotechnology companies, Genzyme is
dedicated to making a major positive impact on the lives of people
with serious diseases. Since its founding in 1981, the company has
introduced breakthrough treatments that have provided new hope for
patients. The company's areas of focus are rare genetic diseases,
multiple sclerosis, cardiovascular disease, and endocrinology.
Genzyme is a Sanofi company. Genzyme's press releases and other
company information are available at http://www.genzyme.com [http://
cts.businesswire.com/ct/CT?id=smartlink&url=http%3A%2F%2Fwww.genzyme.
com&esheet=6385016&lan=en-US&anchor=www.genzyme.com&index=3&md5=65dc7
76b65f6d13feaa795379e70d40d ] .

Genzyme's Multiple Sclerosis business unit is responsible for the
development of teriflunomide, along with the investigational MS
therapy alemtuzumab.

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 and in New York
.

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approval and commercial success of therapeutic alternatives, the
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as those discussed or identified in the public filings with the SEC
and the AMF made by Sanofi, including those listed under "Risk
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ots Originaltext: sanofi-aventis Group
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Contact:
Contacts: Sanofi Media Relations, Jean-Marc Podvin, Tel:
+33(0)1-53-77-46-46, E-mail: mr@sanofi.com ; Genzyme Media Relations,
Bo
Piela, Tel: +1-617-768-6579, E-mail: bo.piela@genzyme.com ; Sanofi
Investor
Relations, Sébastien Martel, Tel: +33(0)1-53-77-45-45, E-mail:
ir@sanofi.com .