Paris and Brisbane, California (ots/PRNewswire) -

- Data Highlighted in Plenary Session of 2009 American Society of
Clinical Oncology Annual Meeting

Sanofi-aventis (EURONEXT: SAN and NYSE: SNY) and its fully owned
subsidiary, BiPar Sciences, today announced results from a randomized
Phase 2 clinical trial of BSI-201, a poly ADP-ribose polymerase
(PARP) inhibitor, in combination with gemcitabine and carboplatin
(GC) chemotherapy, in patients with metastatic triple-negative breast
cancer (TNBC). BSI-201 is a novel investigational agent that acts by
inhibiting PARP1, an enzyme that repairs DNA damage.

In this study, 116 women with metastatic TNBC, defined as tumors
lacking expression of estrogen and progesterone receptors and without
overexpression of HER2, were randomly assigned to receive GC in
combination with the investigational agent BSI-201 or GC alone.
Patients assigned to receive chemotherapy without BSI-201 were
allowed to receive BSI-201 at the time of disease progression.

The primary study endpoint was the rate of clinical benefit,
defined as complete or partial response or stable disease of at least
6 months. Secondary study endpoints included progression-free
survival, overall survival and safety.

Approximately 62 percent of patients receiving BSI-201 in
combination with GC showed clinical benefit, compared with 21 percent
in the group receiving chemotherapy alone (p= 0.0002). Tumor response
(complete or partial response) was observed in 48 percent of patients
who received BSI-201 combined with chemotherapy, whereas patients
receiving chemotherapy alone showed a response rate of 16 percent.
Women who received BSI-201 had a median progression-free survival of
6.9 months and overall survival of 9.2 months compared with 3.3 and
5.7 months, respectively, for women who received chemotherapy alone.
The hazard ratios for progression free survival and overall survival
were 0.342 (p< 0.0001) and 0.348 (p=0.0005), respectively.

The most common severe (grades 3 and 4) side effects included
neutropenia [25/57 in patients treated with GC and BSI-201; 31/59
patients treated with GC alone], thrombocytopenia and anemia. No
febrile neutropenia was observed in patients receiving BSI-201
combined with chemotherapy. BSI-201 did not add to the frequency or
severity of adverse events associated with chemotherapy.

"The improvement in overall survival and progression free
survival together with the responses seen in this study are
promising. We did not observe added toxicities. BSI-201 may provide a
potential new treatment option for patients suffering from this
disease," said Joyce O'Shaughnessy, M.D., co-director of the Breast
Cancer Research Program at Baylor-Charles A. Sammons Cancer Center
and Texas Oncology in Dallas, Texas.

"These results represent an important development for a disease
that currently has no approved standard of treatment," said Barry
Sherman, M.D., BiPar's Executive Vice President of Development.
"Further study of BSI-201 will help us determine its full therapeutic
potential in triple negative breast cancer, as well as in other
cancers".

BiPar Sciences and sanofi-aventis expect to begin a Phase 3
trial with BSI-201 in metastatic TNBC this summer.

About ASCO

ASCO is the world's leading professional organization
representing physicians who care for people with cancer.
Approximately 30,000 cancer specialists from around the world are
expected to gather at ASCO to discuss the latest advances in cancer
care, treatment, prevention and survivorship. More than 4,000
abstracts have been accepted to the meeting, which will focus on the
theme of "Personalizing Cancer Care", a practice focusing on caring
for the individual - not just treating the disease - through the
entire spectrum of care from prevention, diagnosis, and treatment to
survivorship and end of life care. For information on abstract
embargo schedules and other ASCO information and resources, visit
http://www.asco.org/presscenter.

About BSI-201

Among other investigational PARP inhibitors in the industry,
BSI-201 is the furthest along in clinical development in metastatic
TNBC. BSI-201 is currently being evaluated for its potential to
enhance the effect of chemotherapy-induced DNA damage. The clinical
development of BSI-201 is supported by well documented safety profile
based on studies of more than 200 patients.

About TNBC

When patients are diagnosed with breast cancer, their tumors are
routinely tested for the presence of estrogen and progesterone
receptors and for the over-expression of HER2. Commonly used breast
cancer therapies target these receptors; for example, tamoxifen for
estrogen receptor and trastuzumab (Herceptin(r)) for HER2. However,
15-20% of all breast cancers lack over-expression of all three
proteins, thus giving rise to the term "triple- negative breast
cancer" or "TNBC."

TNBC can be an aggressive disease, with higher rates of
metastases and poorer survival rates than other breast cancer
subtypes. No treatment has been approved specifically for TNBC.

About BiPar Sciences

BiPar Sciences is a biopharmaceutical organization pioneering
novel tumor-selective therapies designed to address urgent unmet
needs of cancer patients. In addition to BSI-201, the company also
has two additional compounds in preclinical development. BiPar
Sciences, located in Brisbane, California, is a fully-owned
subsidiary of sanofi-aventis, Inc. For more information, please visit
http://www.biparsciences.com.

About sanofi-aventis

Sanofi-aventis is a leading global pharmaceutical company that
discovers, develops and distributes therapeutic solutions to help
improve the lives of patients. Sanofi-aventis is listed in Paris
(EURONEXT: SAN) and in New York (NYSE: SNY).

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 sanofi-aventis' 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.

ots Originaltext: sanofi-aventis Group
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Contact:
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