MultiStem cell therapy for treatment of ischemic stroke shows promise

Athersys, Inc. has published interim results from its exploratory Phase 2 clinical study of the intravenous administration of MultiStem® cell therapy to treat patients who have suffered an ischemic stroke

Lloyd Dunlap
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CLEVELAND, Ohio—Athersys, Inc. has published interim results from its exploratory Phase 2 clinical study of the intravenous administration of MultiStem® cell therapy to treat patients who have suffered an ischemic stroke. The study results demonstrate favorable safety and tolerability for MultiStem, consistent with prior studies. With respect to the primary and secondary endpoints, the cell therapy did not show a difference at 90 days compared to placebo. However, MultiStem treatment was associated with lower rates of mortality and life threatening adverse events (AEs), infections and pulmonary events. Furthermore, post-hoc analysis shows that patients who received MultiStem treatment earlier in the treatment window had more robust recovery rates in comparison to placebo and relative to patients who received later MultiStem treatment.
Dr. David Hess, lead clinical investigator in the study, stroke specialist and chairman of the Department of Neurology at the Medical College of Georgia at Georgia Regents University, was scheduled to present the summary results at the European Stroke Organization conference on April 19 in Glasgow, Scotland.
Data highlights from the 90-day interim analysis showed that MultiStem cell therapy demonstrated favorable tolerability and safety profile through the evaluation date, which was at least 90 days for all patients. Patients who received intravenous administration of MultiStem did not show a significant difference from placebo-treated patients for the primary endpoint (Global Stroke Recovery Assessment) and the related secondary endpoints—which were defined as the proportion of patients achieving a modified Rankin Scale (mRS) value of 0-2, improvement in the NIH Stroke Scale (NIHSS) by greater than or equal to 75 percent and achieving Barthel Index (BI) greater than or equal to 95 at day 90, however, among all subjects who received MultiStem treatment, 15.4 percent of patients achieved an Excellent Outcome, defined clinically as attaining mRS 0-1, NIHSS 0-1 and BI greater than or equal to 95, compared to 6.6 percent of patients that received placebo, (p=0.10).
Importantly, patients who received MultiStem treatment earlier in the treatment window (24-36 hours post-stroke) exhibited more favorable recovery on the primary and key secondary endpoints than patients who received placebo or patients who received MultiStem treatment later (e.g., Excellent Outcome, p = 0.03), and this treatment effect was even more pronounced the earlier the MultiStem administration within the 24-36 hour timeframe. A higher proportion of patients who received treatment with MultiStem achieved a good clinical outcome by day 7 after treatment, defined as achieving mRS 0-2, which was 12.9 percent for patients receiving MultiStem, compared to 5.2 percent of patients who received placebo, and a similar pattern was seen for improvement in NIHSS greater than or equal to 75 percent, which was achieved by 10.2 percent of MultiStem treated patients vs. 3.9 percent of patients who were treated with placebo. Mortality was lower among patients who received treatment with MultiStem in comparison with placebo. There were 9 subject deaths (14.8 percent) among those receiving treatment with placebo, and only 4 patient deaths (6.2 percent) among patients receiving treatment with MultiStem.
The MultiStem treatment group had a lower rate of life threatening adverse events and death (p=0.04), and also exhibited lower rates of pulmonary events (p=0.08) and infections. The MultiStem treated group also had a significantly lower level of circulating CD-3+ T-cells at two days following dosing (p<0.01), suggesting a reduction in the inflammatory response post-stroke, consistent with the therapeutic hypothesis.
"This exploratory Phase 2 trial represents our first clinical study in stroke and was designed to evaluate the safety and efficacy of a single dose of MultiStem 24-48 hours following the occurrence of the stroke. This treatment window extends well beyond the limits of current standard of care, treatment with tPA, which may only be administered within the first several hours after a stroke," commented Dr. Gil Van Bokkelen, chairman and CEO at Athersys. "Going into this trial, based on extensive preclinical work we have conducted internally and with independent labs, we anticipated that administration of MultiStem could provide several mechanisms of benefit, including down regulation of key inflammatory pathways, up regulation of multiple reparative mechanisms, and could also extend the treatment window in a meaningful way."
"While the trial did not achieve the primary or component secondary endpoints, we believe the evidence indicating that patients who received MultiStem treatment early appeared to exhibit meaningfully better recovery is very important and promising," continued Van Bokkelen. "The results appear to confirm that our window of intervention with MultiStem therapy may extend well beyond the limits of current care. Additional key observations from the trial also appear consistent with key elements of our initial hypothesis. In particular, we are encouraged by the reduced mortality and lower incidence of infections, pulmonary events and life threatening adverse events among MultiStem-treated patients, as well as the limited biomarker data we have seen so far. We anticipate additional data and information from the study and will conduct further analyses to generate more insight about the potential for MultiStem treatment in this area."
"We also continue to advance other clinical programs in acute myocardial infarction (AMI) and acute respiratory distress syndrome (ARDS). In AMI, we have previously published promising data from our Phase 1 study, testing localized delivery of MultiStem shortly following a heart attack, and look forward to completing this Phase 2 study as soon as possible. With respect to ARDS, we are encouraged by the apparent impact in this study on mortality, life threatening adverse events, infection and pulmonary events, which together with our non-clinical study results in pulmonary injury models, suggests the potential for benefit in this patient population. We have a good balance sheet to support this ongoing work and remain confident that our MultiStem therapy and other technologies will have an important impact," concluded Van Bokkelen. 
Ischemic stroke is caused by a blockage of blood flow to the brain. A leading cause of death and disability globally, each year more than 15 million people are estimated to suffer a stroke, including more than two million people in the United States, Japan and European Union, combined. According to the American Heart Association, ischemic strokes comprise more than 85 percent of all strokes. Current standard of care for ischemic stroke involves the administration of a thrombolytic (clot dissolving) agent within three to four hours after a stroke has occurred, a narrow window that results in only a small percentage of patients receiving such treatment.
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 therapeutic factors produced in response to signals of inflammation and tissue damage. MultiStem therapy's potential for multidimensional therapeutic impact distinguishes it from traditional biopharmaceutical therapies focused on a single mechanism of benefit. The product 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. Based upon its efficacy profile, its novel mechanisms of action, and a favorable and consistent safety profile demonstrated in both preclinical and clinical settings, MultiStem therapy could provide a meaningful benefit to patients, including those suffering from serious diseases and conditions with unmet medical need.
Athersys is an international 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, initially for disease indications in the cardiovascular, neurological, inflammatory and immune disease areas, and has several ongoing clinical trials evaluating this potential regenerative medicine product. Athersys has forged strategic partnerships and collaborations with leading pharmaceutical and biotechnology companies, as well as world-renowned research institutions to further develop its platform and products.

Lloyd Dunlap

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