Release issued 5th August 2002

Athersys Inc. today announced that it has successfully completed the initial phase of its alliance with Bristol-Myers Squibb Company (NYSE: BMY) and has expanded the collaboration to include the delivery of additional validated drug targets during the next 3 years, with guaranteed yearly minimums. The agreement covers the use of the targets for drug discovery in multiple therapeutic areas.

The companies originally entered into a research and development collaboration in January 2001. Under the terms of that agreement, Athersys applied its RAGE-VT(tm) technology to provide Bristol-Myers Squibb with an initial set of validated drug targets for use in pharmaceutical screening and development. The collaboration anticipated a potential expansion upon successful conclusion of the initial phase, at the option of both companies.

Bristol-Myers Squibb plans to use its combinatorial chemistry capabilities to develop small molecule drug candidates against the validated drug target cell lines produced and optimized for high-throughput screening by Athersys. In exchange, Athersys will receive license fees for each target cell line, as well as milestone payments on the development of therapeutic candidates, and royalty payments on sales of products that are developed by Bristol-Myers Squibb against the designated drug targets.

"Athersys is committed to partnering with leading pharmaceutical companies like Bristol-Myers Squibb to provide access to cell lines expressing validated biological targets for applications in high-throughput drug screening and lead compound optimization. Our relationship with Bristol- Myers Squibb has been highly successful and the expansion of this collaboration marks an important landmark for Athersys," said Gil Van Bokkelen, Ph.D., chairman, president and chief executive officer of Athersys. "This collaboration is in keeping with our overall business strategy to improve our partners' access to drug targets, while using the revenues from these collaborations to build our in-house pipeline of novel therapeutics."

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 ExpressionÔ) and SMCÔ (Synthetic MicrochromosomeÔ) 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

--Page 1 of 2-- 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 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

(13th December 2001) ATHERSYS TO PROVIDE PFIZER WITH DRUG TARGETS