Athersys, Inc. announced that it continues to enroll patients in its MASTERS-2 trial, the Company?s pivotal Phase 3 trial evaluating MultiStem for the treatment of adults who have suffered an acute ischemic stroke. As of August 7, 2023, the Company has surpassed 2/3 patient enrollment in this 300-patient trial. As previously announced in March 2023, the Company held a Type B Meeting with the U.S. Food & Drug Administration and received approval on recommended protocol changes to the trial, including changing the Primary Endpoint to mRS Shift Analysis at Day 365 and adding an unblinded interim analysis for the purpose of study size adjustment.

More than 60% of active clinical sites have implemented the FDA approved trial modifications and the Company expects the remaining clinical sites to be complete by the end of August 2023. In addition, the Company plans to conduct the unblinded interim analysis in the next few weeks and anticipates the results will be available to share in early October 2023. In addition to approving the request for an interim analysis, the FDA is allowing the Company the opportunity to perform a subset analysis.