Athersys Shares Pummeled as Ischemic Stroke Study Misses Endpoint

Stroke

A study conducted by Athersys partner Healios on a potential treatment for ischemic stroke may have failed to meet the primary endpoint but consistent improvement observed in the long term and in other age groups still seems to support its high potential for success.

Topline results from the TREASURE trial, which evaluates the use of MultiStem cell (invimestrocel) on patients with moderate to moderate-severe ischemic stroke, showed that the drug did not achieve statistical significance based on the primary endpoint of Excellent Outcome at 90 days.

When the participants were evaluated after one year, Excellent Outcome remained insignificant in MultiStem versus the placebo group, but Global Recovery was at 27.9% versus 15.7% and Barthel Index ≥95 was at 35.6% versus 22.5%. The latter two are used as measures of functional independence and positive outcomes.

Because the study failed to meet the primary endpoint, Athersys’ shares dropped 43% on Friday. However, despite the outcome, researchers remained unfazed as an earlier study, MASTERS-1, had shown positive results.

The TREASURE study assesses MultiStem cells in patients with a median age group of 78 years, while the median age in the MASTERS-1 study was 63 years. Another upcoming study, MASTERS-2, will be observing a significantly younger population with lower average stroke severity. The TREASURE trial's contribution to the discovery of a treatment for ischemic stroke is defining the right age group for the drug and refining expectations for the MASTERS-2 trial.

"The TREASURE results demonstrate therapeutic impact on multiple clinically relevant endpoints in this population of older stroke patients, with continued improvement over time. We are particularly pleased by the results for the younger TREASURE study patients who are most relevant to our ongoing MASTERS-2 trial, which we believe suggest a high potential for success in the study," commented Dr. John Harrington, the chief scientific officer of Athersys.

Athersys is working closely with its partner Healios to continue analyzing TREASURE data, including factors associated with the effects of the treatment and its impact on biomarkers. The companies are also preparing for future regulatory applications in Japan.

As regards the MASTERS-2 trial, Athersys said it will refine enrollment processes through site productivity and expansion initiatives to complete the study as soon as possible. The company is also planning to conduct a Phase III study in the U.S., Asia-Pacific and Europe soon.

"The TREASURE study enrolled an elderly stroke population with a median age of 78 years, making these results even more remarkable. We are excited about the MASTERS-2 study and the potential to add a new, clinically meaningful treatment option to stroke clinicians and patients," added David Hess, M.D., the investigator and lead author of the MASTERS-1 study, in the same announcement.

TREASURE involved 206 patients; MASTERS-1 had 126 patients while MASTERS-2 is targeting to enroll 300 patients.

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