Release issued 13th December 2001

CLEVELAND, Ohio, December 13, 2001 - Athersys Inc. today announced it has entered into a drug discovery collaboration with Pfizer (NYSE: PFE) to provide cell lines expressing protein drug targets.

Athersys will use its proprietary RAGE (Random Activation of Gene Expression (TM)) technology platform to provide Pfizer with human cell lines expressing specific protein drug targets, which are also optimized for use in high-throughput drug screening programs. Athersys will receive licensing fees for each validated target cell line it delivers, milestone payments on the development of candidate therapeutics, and milestone or royalty payments based on sales of products that are developed by Pfizer using the RAGE technology.

"This is our fourth collaboration for the RAGE-VT (TM) technology, indicating the high value placed on Athersys' ability to rapidly provide drug targets for the discovery and development of new therapeutic products," said Dr. Gil Van Bokkelen, chairman, president and chief executive officer of Athersys. "Our technology provides leading pharmaceutical companies like Pfizer with access to biological targets. The RAGE platform is enabling a significant number of drug discovery programs to move forward."

Athersys is a functional genomics and biopharmaceutical company engaged in the development, application and commercialization of novel gene expression tools and therapeutic products. The company's research and development programs are focused on its two proprietary platform technologies: RAGE (Random Activation of Gene Expression (TM)) and SMC (TM) (Synthetic Microchromosome (TM)) vector system. RAGE is a novel gene expression system that provides the unique ability to produce protein from virtually every gene in the human genome, without requiring the cloning of individual genes or use of cDNA libraries. RAGE greatly accelerates the identification and validation of novel drug targets by enabling the direct correlation of a disease process or characteristic with expression of a specific protein. As a result, RAGE has powerful applications in functional genomics; the generation of validated drug targets; discovery of novel antibody drug targets; structural proteomics and rational drug design; and the production of protein therapeutics. Athersys is developing novel therapeutic products based on its proprietary technologies, through partnerships and internal research and development programs. This press release and further information on Athersys, Inc. can be found on the World Wide Web at: www.athersys.com.

Statements herein that are not descriptions of historical facts are forward-looking and subject to risk and uncertainties. Actual results could differ materially from those currently anticipated due to a number of factors, including risks relating to the early stage of products under development; uncertainties related to patent protection; uncertainties relating to clinical trials; dependence on third parties, including strategic partners, collaborators and key personnel; and risks relating to the development and commercialization, if any, of Athersys' proposed products (such as effectiveness of our products, marketing, manufacturing, safety, regulatory, patent or product liability, supply, competition and other risks).

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(23rd May 2002) Athersys Issued Patent for Secreted Protein Activation, Production

(23rd May 2002) ATHERSYS CO-FOUNDER AND CHIEF SCIENTIFIC OFFICER NAMED ONE OF THE WORLD'S TOP YOUNG INNOVATORS BY TECHNOLOGY REVIEW, MIT'S MAGAZINE OF INNOVATION

(13th May 2002) ATHERSYS ANNOUNCES COMPLETION OF $16.2 MILLION PRIVATE PLACEMENT FINANCING

(13th May 2002) ATHERSYS INC. NAMED TO THE RED HERRING 100