Sanofi pasteur, the vaccines business of the sanofi-aventis Group (NYSE: SNY), initiated its first clinical study today with a new generation of seasonal influenza vaccine produced using cell culture technology. This trial represents one of the company's initiatives to diversify flu vaccine manufacturing technologies.

The trial conducted in the United States is part of a contract awarded by the U.S. Department of Health and Human Services (HHS) to accelerate the development of a new cell culture-based influenza vaccine.

"This trial will assess the safety and ability to generate an immune response of a cell culture-based vaccine that could provide an important alternative to traditional egg-based flu vaccines," said Dennis Morrison, MD, Clinical Investigator at the first trial site, Bio-Kinetic Clinical Applications, Inc. in Springfield, Missouri. The clinical study is the first step toward sanofi pasteur filing a Biologics License Application with the Food and Drug Administration (FDA) to support development of a cell culture- based trivalent split inactivated seasonal influenza vaccine.

The phase I clinical trial will be conducted on 100 healthy adults, 18-64 years of age. Half of the study participants will receive the cell-based vaccine and the other half a traditional egg-based control vaccine. "We are pleased to participate in a study that evaluates next-generation influenza vaccines," said Cynthia Strout, MD, Clinical Investigator at the second trial site, the Coastal Carolina Research Center in Mt. Pleasant, South Carolina.

This vaccine was developed using PER.C6(R) cell culture technology, licensed from Dutch biotechnology company, Crucell N.V. Cell culture technology could allow sanofi pasteur to diminish dependence on eggs while offering a reliable production technology.

The production scale potential of the PER.C6 cell line has been demonstrated in a successful bioreactor run of 20,000 liters. This project breaks new ground in vaccines technology by demonstrating effective large scale production capacity using cell culture on a commercial scale. This scale-up process was achieved under a subcontracting agreement between sanofi pasteur and Lonza Biologics plc, a biotechnology contract manufacturer and subsidiary of the Lonza Group.

As the world leader in the research, development and manufacture of influenza vaccine, sanofi pasteur is actively involved in other projects in the U.S. and Europe with the goal of developing new and improved influenza vaccines.

Seasonal Influenza Overview

Influenza is a highly infectious virus that spreads easily from person to person, primarily when an infected individual coughs or sneezes. According to the World Health Organization (WHO), 5-15% of the population is affected with upper respiratory tract infections in annual influenza epidemics. Hospitalization and deaths mainly occur in high-risk groups (elderly or people with chronic conditions/illness). Although difficult to assess, these annual epidemics are thought to result in between three and five million cases of severe illness and between 250,000 and 500,000 deaths every year around the world. Most deaths currently associated with influenza in industrialized countries occur among the elderly over 65 years of age.

About Lonza

Lonza is a chemical and biotechnology company headquartered in Switzerland. Lonza is listed on the SWX Swiss Exchange. For more information, please visit http://www.lonza.com.

About Crucell

Crucell N.V. is a Dutch biotechnology company (Euronext, Nasdaq: CRXL; Swiss Exchange: CRX). For more information, please visit http://www.crucell.com.

About sanofi pasteur and Crucell Exclusive Agreement

Sanofi pasteur, the vaccines business of the sanofi-aventis Group, entered on December 31, 2003 into a strategic and exclusive agreement with Crucell N.V. to further develop, manufacture and market cell-based novel influenza vaccine products based on Crucell's proprietary PER.C6 cell line technology. The agreement covers both pandemic and seasonal influenza vaccines.

Crucell's PER.C6 technology is a cell line developed for the large-scale manufacture of biological products including vaccines.

About sanofi-aventis

The sanofi-aventis Group is the world's third-largest pharmaceutical company, ranking number one in Europe. Backed by a world-class R&D organization, sanofi-aventis is developing leading positions in seven major therapeutic areas: cardiovascular disease, thrombosis, oncology, metabolic diseases, central nervous system, internal medicine and vaccines. The sanofi- aventis Group is listed in Paris (EURONEXT: SAN) and in New York (NYSE: SNY).

Sanofi pasteur, the vaccines business of the sanofi-aventis Group, sold more than a billion doses of vaccine in 2005, making it possible to protect more than 500 million people across the globe. The company offers the broadest range of vaccines compared to other vaccine companies, providing protection against 20 bacterial and viral diseases. For more information, please visit: http://www.sanofipasteur.com.

Forward Looking Statements

This press release contains forward-looking statements as defined in the Private Securities Litigation Reform Act of 1995. 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 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 "expect," "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, 2005. Other than as required by applicable law, sanofi-aventis does not undertake any obligation to update or revise any forward-looking information or statements.

sanofi pasteur
http://www.sanofipasteur.com