Covance and Sanofi-Aventis Sign Definitive Agreements for 10-Year Strategic R&D Alliance

Sanofi-Aventis Names Covance its R&D Partner as part of US$2.2 Billion Agreement -

PRINCETON, New Jersey, September 30, 2010 - Covance Inc. (NYSE: CVD) today announced the signing of definitive
agreements with sanofi-aventis (EURONEXT: SAN and NYSE: SNY) for Covance to
become sanofi-aventis' R&D partner. Over the next ten years, Covance expects
to provide drug development services to sanofi-aventis, with estimated
payments ranging from approximately US$1.2 billion to US$2.2 billion.
Sanofi-aventis will sell their Porcheville, France and Alnwick, United
Kingdom sites and facilities to Covance for approximately US$25 million and
Covance will maintain employment on these sites for at least the next five
years. The transaction is expected to be completed before the end of the
year.

"A key strategy for sanofi-aventis is to transform its R&D model and
discover new medicines through the use of novel technologies and innovative
partnerships," declared Marc Cluzel, M.D., PhD, Executive Vice-President,
Research & Development, sanofi-aventis. "This alliance with Covance will help
us preserve hundreds of valuable jobs in Porcheville and Alnwick, while
driving our R&D efficiency for the benefit of the patients."

"We look forward to welcoming the world-class scientific talent in
Porcheville and Alnwick to Covance, as well as adding state-of-the-art assets
and new services to our portfolio," said Joe Herring, Covance Chairman and
Chief Executive Officer. "Today's announcement represents another win-win
solution to the R&D productivity challenges facing the pharmaceutical
industry and provides Covance with a unique source of growth."

Under the agreements, sanofi-aventis will utilize Covance's global R&D
portfolio of discovery support, toxicology, chemistry, clinical Phase I - IV,
central laboratory, and market access services with annual commitments for
these services increasing over the next decade. These agreements include a
10-year sole-source relationship for central laboratory services. Covance
will acquire CMC (Chemistry, Manufacturing and Controls) services with the
addition of the Porcheville and Alnwick sites, including preformulation, drug
formulation, preclinical and early-stage clinical API (Active Pharmaceutical
Ingredient) manufacturing, and radiolabeled chemistry.

Covance will host an investor teleconference and webcast today at 9:00
a.m. USA ET to discuss its strategic alliance with sanofi-aventis. The live
investor call will be available via webcast at www.covance.com and by
listen-only telephone: USA/Canada toll-free: 888-809-5987 or International:
+1-719-325-2334 (participant code: 7106804). An archived call will be
available by the end of the day via webcast at www.covance.com and via
telephone at USA/Canada toll free: 888-203-1112 or International:
+1-719-457-0820 (participant code: 7106804).

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).

About Covance

Covance, with headquarters in Princeton, New Jersey, is one of the
world's largest and most comprehensive drug development services companies
with annual revenues greater than US$1.8 billion, global operations in more
than 30 countries, and more than 10,000 employees worldwide. Information on
Covance's products and services, recent press releases, and SEC filings can
be obtained through its website at www.covance.com.

Forward Looking Statements

Statements contained in this press release, which are not historical
facts, such as statements about prospective earnings, savings, revenue,
operations, revenue and earnings growth and other financial results are
forward-looking statements pursuant to the safe harbor provisions of the
Private Securities Litigation Reform Act of 1995. All such forward-looking
statements including the statements contained herein regarding anticipated
trends in the Company's business are based largely on management's
expectations and are subject to and qualified by risks and uncertainties that
could cause actual results to differ materially from those expressed or
implied by such statements. These risks and uncertainties include, without
limitation, competitive factors, outsourcing trends in the pharmaceutical
industry, levels of industry research and development spending, the Company's
ability to continue to attract and retain qualified personnel, the fixed
price nature of contracts or the loss of large contracts, risks associated
with acquisitions and investments, the consummation of the transaction with
sanofi-aventis, the Company's ability to increase order volume, the pace of
translation of orders into revenue in late-stage development services, and
other factors described in the Company's filings with the Securities and
Exchange Commission including its Annual Report on Form 10-K and Quarterly
Reports on Form 10-Q. The Company undertakes no duty to update any forward
looking statement to conform the statement to actual results or changes in
the Company's expectations.

Media: Laurene Isip, +1-609-419-2466 or Investors: Paul Surdez, +1-609-452-4807