Athersys announces planned amendments to its MASTERS-2 trial protocol

Athersys announced planned amendments to its MASTERS-2 clinical trial protocol following a Type B meeting with the U.S. Food & Drug Administration, FDA. Held on March 21, 2023, the meeting addressed Athersys’ proposed modifications that seek to establish primary and secondary endpoints that it believes best reflect the full potential benefit of MultiStem treatment for patients with acute, moderate-to-severe ischemic stroke as well as the evolving standard of care. Following a meeting Athersys convened in November 2022 of leading stroke experts, regulatory specialists, and statisticians to discuss potential changes, Athersys proposed four modifications to its ongoing pivotal Phase 3 MASTERS-2 clinical trial protocol, all of which were accepted by the FDA. After finalizing agreement around the statistical approach, Athersys will implement the following amendments to the MASTERS-2 protocol: Athersys will change the timing of the primary endpoint assessed by shift analysis in modified Rankin Scale score to Day 365, from Day 90 previously. Athersys will retain shift analysis in mRS score at Day 90 as a key secondary endpoint, along with other revised secondary endpoints. Athersys will remove eligibility caps on concomitant reperfusion therapy to ensure the final study population is reflective of current standard of care in the population eligible for this therapy. Athersys may elect to have an independent statistician conduct an interim analysis to assess potential sample size adjustment. MASTERS-2 currently plans to enroll 300 patients and enrollment, as previously communicated, is greater than 50% complete.