Release issued 23rd May 2002

As co-founder, Executive Vice President and Chief Scientific Officer of Athersys, Dr. Harrington is responsible for the day to day operations of the Company's research and development programs as well as the continued development of the Company's two proprietary platform technologies: RAGE (Random Activation of Gene Expression(tm)) for functional genomics, proteomics and drug discovery and the SMC(tm) (Synthetic Microchromosome(tm)) vector system for gene therapy. Athersys' RAGE technology enables the expression and production of virtually every protein in the human genome, leading to an accelerated, more efficient drug discovery process. Currently, Athersys has product development programs in oncology, inflammation, neurobiology and developmental biology.

To date, Athersys has raised approximately $100 million and has established strategic partnerships with a number of leading pharmaceutical and biotechnology companies, including Bristol-Myers Squibb, Pfizer, Medarex and 3- Dimensional Pharmaceuticals.

Dr. Harrington is being honored today during a conference and awards ceremony at the Massachusetts Institute of Technology. The event, themed "The Innovation Economy: How Technology is Transforming Existing Businesses and Creating New Ones", includes a full day of conference sessions and panel discussions followed by an evening gala awards ceremony. Hosted by Technology Review's Editor-in- Chief John Benditt and CNBC's Consuelo Mack, conference speakers include international leaders such as Kenneth Starr Esq.; Clayton Christensen, Harvard Business School professor and author of The Innovators Dilemma; Nadine Strossen, President of the ACLU; Rodney Brooks, Director of the Artificial Intelligence Laboratory and Co-director of Project Oxygen, MIT; Richard Rashid, Senior Vice President, Microsoft Research; and David Tennenhouse, Vice President and Corporate Technology Group Director, Intel Corporation.

TR100's unparalleled panel of judges includes:

Dr. David Baltimore, President, California Institute of Technology Alfred Berkeley III, Vice Chairman, NASDAQ Richard Demillo, Vice President and Chief Technology Officer, Hewlett-Packard Dr. Philippe Janson, Vice President, IBM Academy of Technology Dr. Robert M. Metcalfe, Venture Partner, Polaris Venture Partners Dr. Cherry A. Murray, Senior Vice President of Physical Science Research, Bell Labs/Lucent Technologies Nicholas Negroponte, Director, MIT Media Laboratory Dr. Judith Rodin, President, University of Pennsylvania

Athersys is a functional genomics and biopharmaceutical company engaged in the development, application and commercialization of therapeutic products and novel gene expression tools. 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).

(5th August 2002) ATHERSYS EXPANDS PARTNERSHIP WITH BRISTOL-MYERS SQUIBB

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

(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