Athersys Confirms Completion of Patient Enrollment of Pfizer's Phase II Study of MultiStem(R) Cell Therapy for Ulcerative

Athersys Confirms Completion of Patient Enrollment of Pfizer's Phase II Study
of MultiStem(R) Cell Therapy for Ulcerative Colitis

Top-Line Data Readout Expected in Second Quarter 2014

CLEVELAND, Dec. 19, 2013 (GLOBE NEWSWIRE) -- Athersys, Inc. (Nasdaq:ATHX)
today announced that Pfizer Inc. has completed patient enrollment of a Phase
II clinical study involving administration of Athersys' MultiStem^® cell
therapy to ulcerative colitis patients as part of a 2009 collaboration
agreement between Athersys and Pfizer. The study is a randomized,
double-blind, placebo-controlled, multi-center clinical trial evaluating the
safety and efficacy of MultiStem therapy in subjects with moderate to severe
ulcerative colitis. Athersys expects initial results from the study to be
disclosed in the second quarter of 2014.

"With enrollment now completed, we and our partner, Pfizer, look forward to
the results from this study," commented Dr. John Harrington, Chief Scientific
Officer at Athersys. "Despite progress in recent years, there remains a
substantial need for new and improved treatments for ulcerative colitis and
Crohn's disease, especially among patients with more advanced disease.Based
upon MultiStem's preclinical safety and efficacy profile and novel mechanisms
of action, we believe that MultiStem could provide meaningful benefit to these
patients.The results from this study should provide significant insight into
the potential for MultiStem therapy for the treatment of inflammatory bowel

Inflammatory bowel disease (IBD) is a group of inflammatory and autoimmune
conditions that affect the colon and small intestine, typically resulting in
severe abdominal pain, weight loss, vomiting and diarrhea.The most common IBD
conditions include ulcerative colitis and Crohn's disease, which are estimated
to affect four million people or more in the United States, the major European
markets and Japan.IBD can be a severely debilitating condition, and advanced
cases may require surgery to remove the affected region of the bowel, and may
also require temporary or permanent colostomy or ileostomy.In many cases,
surgery does not achieve a permanent or durable cure, and patients suffer a
return of the disease.

The randomized, double-blind, placebo-controlled Phase II clinical trial is
being conducted by Pfizer at sites in the United States, Canada and
Europe.Subjects enrolled in the study have received either MultiStem
treatment or placebo initially, followed by a second round of treatment with
MultiStem cells or placebo at eight weeks, resulting in two groups for
evaluation through eight weeks and four groups for evaluation through 16 weeks
and beyond.The primary endpoints for the study include incidence and severity
of adverse events over 16 weeks, change in endoscopic score (as measured by
modified Baron score) at week eight, and changes in the Mayo rectal bleeding
sub-score at weeks four and eight.Additionally, there are multiple secondary
and exploratory endpoints evaluating disease indicators and markers over 16
weeks and through the entire study period.

Athersys expects that study data will be available in the second quarter 2014
in two parts.The firstresults, anticipated to be available in April or May,
will describe the primary endpoints and certain secondary and exploratory
endpoints for all subjects through eight weeks following the initial
treatment.The second results, expected later in the second quarter, will
cover additional data for subjects through 16 weeks following treatment.

About MultiStem

MultiStem cell therapy is a patented regenerative medicine product that has
shown the ability to promote tissue repair and healing in a variety of ways,
such as through the production of multiple therapeutic factors produced in
response to signals of inflammation and tissue damage.MultiStem has
demonstrated therapeutic potential for the treatment of inflammatory and
immune disorders, neurological conditions, and cardiovascular disease, as well
as other areas.It represents a unique "off-the-shelf" stem cell product that
can be manufactured in a scalable manner, may be stored for years in frozen
form, and is administered without tissue matching or the need for immune
suppression.The product is extensively characterized for safety, consistency
and potency.Athersys has forged a strategic partnership with Pfizer Inc. to
develop MultiStem for treating inflammatory bowel disease, while independently
evaluating it as a novel therapeutic approach for indications in the
neurological, cardiovascular and transplant support areas, as well as other
potential opportunities.

About Athersys

Athersys is a clinical stage biotechnology company engaged in the discovery
and development of therapeutic product candidates designed to extend and
enhance the quality of human life. The Company is developing its MultiStem^®
cell therapy product, a patented, adult-derived "off-the-shelf" stem cell
product platform for disease indications in the cardiovascular, neurological,
inflammatory and immune disease areas. The Company currently has several
clinical stage programs involving MultiStem, including for treating
inflammatory bowel disease, ischemic stroke, damage caused by myocardial
infarction, and for the prevention of graft-versus-host disease. Athersys has
also developed a diverse portfolio that includes other technologies and
product development opportunities, and has forged strategic partnerships and
collaborations with leading pharmaceutical and biotechnology companies, as
well as world-renowned research institutions in the United States and Europe
to further develop its platform and products. More information is available at

The Athersys, Inc. logo is available at:

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of
the Private Securities Litigation Reform Act of 1995 that involve risks and
uncertainties. These forward-looking statements relate to, among other things,
the expected timetable for development of our product candidates, our growth
strategy, and our future financial performance, including our operations,
economic performance, financial condition, prospects, and other future events.
We have attempted to identify forward-looking statements by using such words
as "anticipates," "believes," "can," "continue," "could," "estimates,"
"expects," "intends," "may," "plans," "potential," "should," "suggest,"
"will," or other similar expressions. These forward-looking statements are
only predictions and are largely based on our current expectations. A number
of known and unknown risks, uncertainties, and other factors could affect the
accuracy of these statements. Some of the more significant known risks that we
face that could cause actual results to differ materially from those implied
by forward-looking statements are the risks and uncertainties inherent in the
process of discovering, developing, and commercializing products that are safe
and effective for use as human therapeutics, such as the uncertainty regarding
market acceptance of our product candidates and our ability to generate
revenues, including MultiStem for the treatment of inflammatory bowel disease,
acute myocardial infarction, stroke and other disease indications, including
lysosomal storage disorders, and the prevention of graft-versus-host disease.
These risks may cause our actual results, levels of activity, performance, or
achievements to differ materially from any future results, levels of activity,
performance, or achievements expressed or implied by these forward-looking
statements. Other important factors to consider in evaluating our
forward-looking statements include: our ability to raise additional capital;
the timing of the results from Pfizer's Phase II clinical study involving
MultiStem cell therapy to ulcerative colitis patients; final results from our
MultiStem clinical trials; the possibility of delays in, adverse results of,
and excessive costs of the development process; our ability to successfully
initiate and complete clinical trials; changes in external market factors;
changes in our industry's overall performance; changes in our business
strategy; our ability to protect our intellectual property portfolio; our
possible inability to realize commercially valuable discoveries in our
collaborations with pharmaceutical and other biotechnology companies; our
ability to meet milestones under our collaboration agreements; our
collaborators' ability to continue to fulfill their obligations under the
terms of our collaboration agreements; the success of our efforts to enter
into new strategic partnerships and advance our programs; our possible
inability to execute our strategy due to changes in our industry or the
economy generally; changes in productivity and reliability of suppliers; and
the success of our competitors and the emergence of new competitors. You
should not place undue reliance on forward-looking statements contained in
this press release, and we undertake no obligation to publicly update
forward-looking statements, whether as a result of new information, future
events or otherwise.

CONTACT: William (B.J.) Lehmann, J.D.
         President and Chief Operating Officer
         Tel: (216) 431-9900
         Investor Relations:
         Lisa M. Wilson
         In-Site Communications
         Tel: (917) 543-9932

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