Factsheet

Athersys

CORPORATE FACT SHEET 2008

i n c.

CORPORA TE PROFILE CORPORATE Athersys is a biopharmaceutical company engaged in the discovery and development of therapeutic product candidates designed to extend and enhance the quality of human life. Through the application of our proprietary technologies, we have established a pipeline of highly differentiated, potential “best-in-class” candidate therapeutics. Athersys is committed to the development of therapeutic products that have the potential to extend and enhance the quality of human life. One of our lead development programs is focused on a proprietary non-embryonic stem cell product candidate, MultiStem®, that we believe has potential utility for treating a broad range of diseases and could have widespread application in the field of stem cell medicine. MultiStem is a drug-like, proprietary stem cell product that is produced on a commercial scale by obtaining stem cells from consenting donors. The cells are capable of expressing multiple proteins and other factors involved in tissue repair and immune system regulation, such as reducing inflammation. Once obtained from a donor, the cells are processed and expanded on a commercial scale using proprietary techniques and manufacturing processes. Along with collaborators from leading research and clinical institutions, we have conducted extensive studies examining

the safety and effectiveness of MultiStem in preclinical models of human disease, and have received FDA authorization to conduct multiple clinical trials applying MultiStem. Current trials include administering MultiStem in patients that have suffered a severe heart attack (myocardial infarction) and for cancer treatment support (such as to reduce or prevent graft versus host disease (GVHD) in leukemia patients). In December 2008, we received FDA authorization to initiate a clinical study in patients suffering from an ischemic stroke, which represents the leading cause of disability in the United States, and the third leading cause of death. Working in collaboration with independent experts, we have also demonstrated the potential for MultiStem in other disease areas, and will continue to explore potential applications. We are also developing novel, orally active pharmaceutical products for the treatment of central nervous system disorders, including sleep disorders such as narcolepsy or excessive daytime sleepiness, and other potential indications such as attention deficit hyperactivity disorder, or ADHD, as well as other cognitive disorders. Additionally, we are developing nextgeneration back-up compounds that target the 5HT2c receptor, a key neurotransmitter receptor in the brain associated with appetite regulation.

KEY PROGRAMS MultiStem® for Bone Marrow Transplant Support, Acute Myocardial Infarction, and Stroke MultiStem is a biologic product that consists of undifferentiated human stem cells obtained from adult bone marrow or other non-embryonic tissue sources. Material from a single qualified donor may be used to produce hundreds of thousands of clinical doses or more. MultiStem has great potential as a “best-in-class” cell therapy based on the potential to deliver a therapeutic benefit through multiple mechanisms of action, its ability to be delivered “off-the-shelf” like a pharmaceutical product, and its safety profile. Histamine H3 Receptor Antagonists The H3 receptor regulates levels of histamine and other neuro-transmitters in certain

areas of the brain that play a direct role in regulating sleep and cognitive function. Our histamine H3 receptor antagonists represent a new class of drugs that could have an improved efficacy and safety profile relative to existing drugs used for the treatment of narcolepsy and related sleep disorders, or other conditions. 5HT2c Agonists The 5HT2c serotonin receptor plays an important role in the regulation of appetite. Numerous prior studies have demonstrated that stimulation of the 5HT2c receptor causes a significant reduction in appetite, resulting in weight loss over time. We are developing potent, selective, 5HT2c agonists for the treatment of obesity and potentially other indications.

DEVELOPMENT ST ATUS OF KEY PROGRAMS (THIRD QUARTER 2008) STA

CORPORATE FACT SHEET 2008 THIRD QUAR TER (2008) HIGHLIGHTS QUARTER ■ Revenues of $1.3 million and a net loss of $4.5 million were

recorded for the quarter ended September 30, 2008; ■ Announced successful initial patient dosing of MultiStem in

Phase I AMI trial; ■ Initiated patient dosing of MultiStem in Phase I trial for

GvHD; ■ Received Frost & Sullivan’s 2008 North American Product

■ Bristol-Myers Squibb notified Athersys that it has initiated a

Phase II trial for a small molecule discovered using a target provided by the Company, thereby triggering a milestone fee payment; ■ Company added to the Russell Microcap® Index in July 2008; ■ Favorable capital position of $34.7 million in cash, cash

equivalents and available-for-sale securities.

Innovation of the Year Award for MultiStem;

SELECTED FINANCIAL DA TA DAT

Key Ratios (December 3, 2008) Price & Volume

Valuation Ratios

Recent Price $

0.35

Price/Earnings (TTM)

N/A

52 Week High $

5.01

Price/Sales (TTM)

1.82

52 Week Low $

0.15

Price/Book (MRQ)

0.19

Price/Cash Flow (TTM)

N/A

Average Vol (Mil) (RTMA)

1.153

Share Related Items

Per Share Data

Market Cap. ($Mil)

6.625

Earnings (TTM) $

Shares Out (Mil)

18.93

Sales (TTM) $

0.19

Float (Mil)

13.10

Book Value (MRQ) $

1.88

Cash Flow (TTM) $

-0.94

Financial Strength Quick Ratio (MRQ)

11.72

Current Ratio (MRQ)

11.72

LT Debt/Equity (MRQ)

0.00

Cash (MRQ) $

-0.95

1.77

Source: Reuters

ANAL YST COVERAGE ANALYST Adam Cutler — Canaccord Adams Phil Nadeau — Cowen and Company Matt Osbourne — Lazard Capital William Tanner, Ph.D. — Leerink Swann Stephen Brozak — WBB Securities

KEY PERSONNEL / CONT ACTS CONTACTS

Management Gil Van Bokkelen, Ph.D. Chairman and CEO John Harrington, Ph.D. Executive VP & Chief Scientific Officer

Robert Deans, Ph.D. Senior Vice President, Regenerative Medicine Laura Campbell, C.P.A Vice President, Finance

William (B.J.) Lehmann Jr., J.D. President & Chief Operating Officer

Athersys i n c.

Corporate Headquarters Athersys, Inc. 3201 Carnegie Avenue Cleveland, OH 44115-2634 eMail Corporate Partnerships: [email protected] Scientific Collaboration: [email protected] Human Resources: [email protected]

Telephone 216-431-9900 FAX 216-361-9495 Investor Relations In-Site Communications, Inc. Lisa M. Wilson 212-759-3929 [email protected]

The information contained herein was obtained from the management of Athersys, Inc. and other sources Athersys believes to be reliable. Except for the historical information contained herein, the matters discussed in this document are forward-looking statements, the accuracy of which is subject to risks and uncertainties. These forward-looking statements should not be relied upon as representing the Company’s views as of any date subsequent to December 4, 2008. Please see Athersys’s most recent Annual Report, Form 10-K and Form 10-Q for additional information about the Company and related risks. “MultiStem” is a trademark belonging to Athersys, Inc.

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