Aventis and Intercell Sign Collaboration and License Agreement to Develop Bacterial vaccines

Swiftwater, PA and Vienna, Austria, February 17, 2004 - Intercell AG and Aventis S.A. announced today the signing of a commercial license agreement for the development of bacterial vaccines.

Under the terms of the agreement, Intercell will apply its Antigen Identification Program (AIP) to identify relevant antigens, which will allow Aventis Pasteur, the vaccines business of Aventis, to develop a next generation protein-based vaccine.

Intercell will receive upfront payments, license fees, research and development funding, milestone payments, and royalty payments on product sales. Aventis Pasteur will receive exclusive worldwide rights to commercialize the vaccines developed in the collaboration. Further financial details of the agreement were not disclosed.

"Aventis Pasteur is a leader and innovator in the vaccine field, and this collaboration validates our capabilities in the development of novel and improved vaccine products," stated Intercell�'s CEO Alexander von Gabain. "Intercell�'s AIP is a novel, utterly comprehensive, rapid genomic technology for identification of the most protective pathogen antigens that are discovered, using human immune responses as the discovery engine."

"This program will enable Aventis Pasteur to maintain its leadership position in next generation vaccine development," commented Dr. Jeffrey Almond, senior vice-president, global research and external R&D at Aventis Pasteur. "We expect that the collaboration will allow Aventis Pasteur to significantly improve its competitive position in the focus area of the collaboration."

About Intercell

Intercell is a biotechnology company focused on the development of vaccines against infectious diseases. Intercell�'s lead products are, a therapeutic hepatitis C vaccine, which has entered Phase II clinical testing in November 2002, and a vaccine against Japanese encephalitis that has successfully undergone a phase II clinical study. A phase III clinical study is planned for 2004.

To date, Intercell AG has succeeded in raising venture capital totaling USD 100 million since becoming operational.

About Aventis

Aventis is dedicated to treating and preventing disease by discovering and developing innovative prescription drugs and human vaccines. In 2003, Aventis generated sales of € 16.79 billion, invested € 2.86 billion in research and development and employed approximately 69,000 people in its core business. Aventis corporate headquarters are in Strasbourg, France.

Aventis Pasteur, the vaccines business of Aventis, produced 1.4 billion doses of vaccine in 2003, making it possible to protect 500 million people across the globe, which is about 1.4 million per day. The company offers the broadest range of vaccines, providing protection against 20 bacterial and viral diseases.

For Intercell

This press release contains forward-looking statements that involve inherent risks and uncertainties. We have identified certain important factors that may cause actual results to differ materially from those contained in such forward-looking statements.

For Aventis

Statements in this news release containing projections or estimates of revenues, income, earnings per share, capital expenditures, capital structure, or other financial items; plans and objectives relating to future operations, products, or services; future economic performance; or assumptions underlying or relating to any such statements, are forward-looking statements subject to risks and uncertainties. Actual results could differ materially depending on factors such as the timing and effects of regulatory actions, the results of clinical trials, the company�'s relative success developing and gaining market acceptance for new products, the outcome of significant litigation, and the effectiveness of patent protection. Additional information regarding risks and uncertainties is set forth in the current Annual Report on Form 20-F of Aventis on file with the Securities and Exchange Commission and in the current Annual Report -"Document de Référence"- on file with the "Commission des Opérations de Bourse" in France, recently renamed "Autorité des marchés financiers".

Aventis Pasteur contact:

Len Lavenda Aventis Pasteur

US Media Relations

Tel.: +1 570 839 4446