Athersys (NASDAQ: ATHX) is an international biotechnology company that is focused in the field of regenerative medicine. We are committed to the development of innovative and best-in-class therapies designed to address areas of significant unmet medical need, and that have the potential to extend and enhance the quality of human life.

We have established a portfolio of therapeutic product development programs focused on treating neurological, inflammatory and immune, and other indications where there is an unmet medical need, and we have a particular emphasis on the critical care area. Our MultiStem® cell therapy, a patented and proprietary, “off-the-shelf” stem cell product, is our lead platform product and is currently being evaluated in several clinical programs, the most advanced of which is a Phase 3 clinical trial for treating stroke patients. This technology has received three Fast Track designations (for stroke, ARDS, and transplant support), RMAT designation from the FDA, as well as Sakigake designation in Japan.

3RD QUARTER 2020NASDAQ: ATHX

Inflammatory, Immune & Related

HSC Transplant / GvHDAcute Respiratory Distress Syndrome

Trauma

Solid Organ Transplant Support

MACOVIA (Athersys) - Fast Track and RMAT Designation by FDA

MATRICS-1 with funding from the DOD (MTEC) and UTHealth

SPA agreement and Fast Track designation by FDA; Orphan drug designation by FDA and EMA

Cardiovascular

Acute Myocardial Infarction

PVD/PAD/CLI

Congestive Heart FailureAbility to move directly

to Phase 2

Neurological

Ischemic Stroke Hemorrhagic Stroke Traumatic Brain Injury Multiple Sclerosis Spinal Cord Injury

Ability to move directly to Phase 2

TREASURE (Healios) - enrollment ongoingPriority review designation from PMDA (Sakigake)

MASTERS-2 (Athersys) - enrollment ongoingSPA, Fast Track and RMAT Designation fromFDA & Positive Scientific Advice from EMA

Preclinical IND/CTA Phase 1 Phase 2 Phase 3 NDA/BLA Commercial

ONE-BRIDGE (Healios) - Orphan Designation - enrollment ongoing

Development Status of Regenerative Medicine Programs

CORPORATEFACT SHEET

KEY PROGRAMS

Approximately 17 million people suffer a stroke every year, and it is the leading cause of long-term serious disability in the world. While there are some treatments available for treating an ischemic stroke, patients must receive these therapies within only a few hours of having a stroke. Unfortunately, only a modest percentage of stroke patients arrive at the hospital in time to receive these remedies.

Athersys is developing MultiStem for the treatment of ischemic stroke, which may be administered to a patient up to 36 hours after the stroke, based on prior clinical results. This could dramatically extend the time window for therapy, potentially enabling up to 90-95% of stroke patients to be eligible to receive the therapy.

We are currently in Phase 3 clinical development for the MASTERS-2 study, our trial for the treatment of ischemic stroke that is being conducted primarily in North America and Europe. This pivotal, 300-patient clinical trial is being run under a Special Protocol Assessment, or SPA, by the FDA for the design and planned analysis. In addition, the program has received multiple regulatory designations meant to expedite approval, including Fast Track designation and Regenerative Medicine Advanced

Therapy, or RMAT, from the FDA. The European Medicines Device Agency, or EMA, granted the program a Final Scientific Advice positive opinion establishing alignment between European and the United States regulators about the potential for approval based on the success of the planned MASTERS-2 study, which further expedites development.

MultiStem is also being evaluated in ischemic stroke patients in the TREASURE trial in Japan, a pivotal clinical trial being conducted by our partner, HEALIOS K.K. (Healios). This double-blind, randomized, placebo-controlled study is enrolling approximately 220 patients at leading stroke centers in Japan and is being conducted under the innovative regulatory framework established for regenerative medicine therapies implemented by the PMDA and MHLW. This framework is designed to expedite the development and commercialization of promising and innovative regenerative medicines that are shown to exhibit safety and demonstrate potential effectiveness. This clinical program has also received Priority Review (or Sakigake) designation in Japan under the regulatory framework for innovative therapies. Enrollment for this trial is expected to be completed in 2020.

Acute respiratory distress syndrome (ARDS) is a serious immunological and inflammatory condition characterized by

widespread inflammation in the lungs. ARDS can be triggered by pneumonia,

sepsis, or trauma and represents a major cause of morbidity and mortality in the critical care

setting. It has significant implications, as it may result in prolonged intensive care unit (ICU) and hospital stays and may also require convalescence in the hospital and rehabilitation. ARDS is the leading cause of death among COVID-19 patients that become seriously or critically ill.

In 2019 we announced positive results for an exploratory Phase 1/2 clinical study evaluating MultiStem cell therapy for the treatment of ARDS. Patients in the double-blind, randomized, placebo-controlled exploratory study were evaluated through 28 days for the primary clinical assessment and were further assessed through a one-year follow-up period. Top line clinical trial results showed meaningful improvements in mortality, ventilator-free days, and ICU-free days among MultiStem treated patients in comparison with patients receiving placebo. Additional data was presented at the 2019 American Thoracic Society International Conference in May 2019.

This program has been granted Fast Track and RMAT designation by the FDA as a result of this promising data.

In April 2020 we initiated the MACOVIA study to evaluate MultiStem cell therapy for the treatment of COVID-19 induced ARDS patients. This trial is a multicenter study with an open-label, single active treatment arm for cohort 1 followed by a double-blind, randomized, placebo-controlled Phase 2/3 portion. The primary objectives of the MACOVIA study are to evaluate the safety and efficacy of MultiStem as a therapy for subjects with moderate to severe ARDS due to COVID-19.

The primary efficacy endpoint will be an evaluation of ventilator-free days through day 28 as compared to placebo, a well-established endpoint for ARDS trials that evaluates an intervention’s combined impact on survival and liberation from invasive mechanical ventilation. The secondary objectives of this study include evaluation of pulmonary function, all-cause mortality, time in intensive care, hospitalization, tolerability and quality of life (QoL) among survivors. The study is designed to enroll approximately 400 subjects and will be conducted at leading pulmonary critical care centers throughout the United States.

KEY PROGRAMS NASDAQ: ATHX 3RD QUARTER 2020

Ischemic Stroke and Other Neurological Programs

Acute Respiratory Distress Syndrome (ARDS)

We believe our technology has broad potential applications in critical care medicine, including complications from trauma, transplant support, and other areas.

In November 2020 we initiated a trauma study with the University of Texas Health Science Center at Houston. The MATRICS-1 study will evaluate MultiStem cell therapy for early treatment and prevention of complications after severe traumatic injury. This first-ever study of cell therapy for the treatment of a wide range of traumatic injuries is being conducted at Memorial Hermann-Texas Medical Center, one of the busiest Level 1 trauma centers in the United States and will receive grant support from the Department of Defense through the Medical Technology Enterprise Consortium (MTEC) and the Memorial Hermann Foundation.

The objective of the clinical study is intended to evaluate the safety and effectiveness of MultiStem as a therapy for severely injured trauma patients, and for the prevention and early treatment of complications after severe traumatic injury. The study is a randomized, double-

blind, placebo-controlled Phase 2 clinical trial estimated to enroll approximately 150 severely-injured trauma patients who have survived initial care and are admitted to the intensive care unit. These patients will be randomly assigned to receive MultiStem or placebo within hours of hospitalization, and both groups will receive standard care for their injuries.

According to the Centers for Disease Control (CDC), trauma is the leading cause of death for individuals under the age of 45 and the third leading cause of death in the United States, accounting for approximately 180,000 fatalities each year. It is also a leading cause of serious disability, especially among young people that suffer trauma and members of the military. The CDC reports that, in the most recent year evaluated, 2013, there were more than 2.5 million emergency department visits for traumatic brain injury (TBI) and more than 282,000 hospitalizations. Over 5 million people in the United States are living with a TBI-related disability, and an estimated 80,000 - 90,000 people suffer a serious disability from TBI each year in the United States at an estimated cost of $37.8 billion, annually.

• Received Regenerative Medicine Advanced Therapy (RMAT) designation for MultiStem® from the U.S. Food and Drug Administration (FDA) for the treatment of acute respiratory distress syndrome (ARDS), a designation enabling additional interactions with the FDA that are focused on expediting development;

• Commenced patient screening for the Phase 2 clinical trial led by The University of Texas Health Science Center at Houston (UTHealth) evaluating MultiStem Administration for Trauma Related Inflammation and Complications (MATRICS-1) in patients at Memorial Hermann-Texas Medical Center, a leading Level 1 Trauma center;

• Further advanced the MACOVIA Phase 2/3 trial evaluating MultiStem administration to patients with COVID-19 induced ARDS and advanced preparations to potentially expand the study to include a broader range of patients with ARDS, including from influenza and other pathogens;

• Advanced the MASTERS-2 ischemic stroke study, reactivating all clinical sites previously impacted by COVID-19 operational disruptions, and adding new sites to the study;

• Received notification that HEALIOS K.K. (Healios), our Japanese partner, completed enrollment of its COVID-19 induced ARDS patient cohort in its ONE-BRIDGE study. Healios has previously stated it intends to complete enrollment of the entire ONE-BRIDGE study and the TREASURE ischemic stroke study by around the end of the year;

• Advanced our partnering negotiations regarding MultiStem for potential commercialization in Europe and other regions of interest; and

• Continued key initiatives for establishing commercialization readiness, including supply chain and logistics, process development, manufacturing, branding and other key areas.

NASDAQ: ATHX 3RD QUARTER 2020

Trauma and Transplantation Support

Multiple Important Objectives Achieved Recently

The information contained herein was obtained from the management of Athersys, Inc. and other sources Athersys believes to be reliable. The matters discussed in this document include forward-looking statements, the accuracy of which is subject to risks and uncertainties. Undue reliance should not be placed on these forward-looking statements and the Company undertakes no obligation to update forward-looking statements. Please see Athersys’s most recent Annual Report, Form 10-K, Form 10-Q, Form 8-K and other SEC filings for additional information about the Company and related risks.

MultiStem® is a registered trademark of Athersys, Inc. Athersys.com

ANALYST COVERAGE

Athersys, Inc.3201 Carnegie Avenue

Cleveland, OH 44115-2634Telephone: 216-431-9900

Fax: 216-361-9495

Greg Harrision - Bank of AmericaDavid Hoang - SMBC Nikko Securities

Jason Kolbert - Dawson JamesChad Messer - Needham & Co, LLC

Stephen Brozak - WBB Securities

Russo Partners, LLCDavid Schull

(212) 845-4271 or (858) 717-2310David.schull@russopartnersllc.com

General Inquires: info@athersys.comHuman Resources: jobs@athersys.com

Investor Relations: ir@athersys.com

MEDIA RELATIONS

EMAIL

CORPORATE HEADQUARTERS

CORPORATE COMMUNICATIONS &INVESTOR RELATIONS

Karen Hunady, (216) 431-9900khunady@athersys.com

NASDAQ: ATHX 3RD QUARTER 2020

Management

Gil Van Bokkelen, PhDChairman and CEO

John Harrington, PhDExecutive Vice President & Chief Scientific Officer

Gregory Liposky, MBA Senior Vice President of Commercial Manufacturing

Manal Morsy, MD, PhD, MBASenior Vice President, Global Regulatory Affairs

Robert (Willie) Mays, PhDVice President of Regenerative Medicine, Head of Neuroscience Programs

Rakesh Ramachandran, MSVice President, Information Technology & Communications

William (B.J.) Lehmann, Jr., JDPresident & COO

Ivor Macleod, MBA, CPAChief Financial Officer

Laura Campbell, CPA Senior Vice President of Finance

Maia Hansen, MBA, MSSenior Vice President, Operations and Supply Chain

Anthony Ting, PhDVice President of Regenerative Medicine, Head of Cardiopulmonary Programs

Eric Jenkins, MDSenior Medical Director and Head of Clinical Operations

SELECTED FINANCIAL DATA(in thousands, except per share data)

Year Ended December 31,2019 2018 2017

Consolidated Statement of Operations Data:Revenues:

Contract Revenue $ 162 $ 5,517 $ 23,737 $ 2,843Grant Revenue 8 116 554 865

Total Revenues 170 5,633 24,291 3,708Costs and Expenses:

Research and development 44,333 39,045 38,656 27,841General and administrative 11,606 11,378 10,442 8,466Depreciation 645 698 855 684 Total costs and expenses 56,584 51,121 49,953 36,991Gain from insurance proceeds, net - 617 - Loss from operations (56,414) (45,488) (25,045) (33,283)Other income, net (145) 906 762 314Income (expense) from change in fair value of warrants - - 728

Net loss and comprehensive loss $ (56,559) $ (44,582) $ (24,283) $ (32,241)Basic loss per share $ (0.31) $ (0.29) $ (0.18) $ (0.29)

Weighted average shares - outstanding, basic 183,841 151,696 136,641 112,053

YTD Ended September

30, 2020