Athersys Modifies Endpoints in Multistem Trial for Ischemic Stroke
The company also recently announced updates in the MATRICS-1 clinical trial for hemorrhagic trauma.
The FDA has accepted Athersys’ proposed modifications to its phase 3 MASTERS-2 clinical trial (NCT03545607) evaluating the cell therapy MultiStem (invimestrocel) for the treatment of ischemic stroke during a Type B meeting convened in late March.1
“The MASTERS-2 clinical trial protocol changes agreed to by the FDA reflect what we have learned from the completed MultiStem Phase 2 MASTERS-1 trial and the TREASURE clinical trial run in Japan by our partner Healios, as well as the significant evolution of standard of care in treating acute ischemic stroke. We appreciate the FDA’s guidance, which we believe ultimately willbenefit stroke patients worldwide,” Dan Camardo, Chief Executive Officer, Athersys, said in a statement.1 “We view the outcome of our meeting as the best-case scenario. Although changing the primary endpoint to Day 365 extends the duration of MASTERS-2, we believe our accepted modifications enable accelerated patient enrollment and provide a higher conviction for demonstrating treatment potential.”
Athersys proposed modifications to MASTERS-2 after holding a meeting with stroke experts in November 2022. These modifications include changing the primary endpoint timing to 365 days after treatment to assess modified Rankin Scale (mRS) score from 90 days, although mRS score at 90 days will be assessed as a secondary outcome.The trial will also no longer cap the concomitant reperfusion therapy that participants are allowed to receive, including tissue plasminogen activity, MR imaging, or both, to reflect the current standard of care in the eligible population. Additionally, Athersys may have an independent statistician conduct an interim analysis and potentially adjust sample sizes depending on the findings. MASTERS-2 has enrolled over 50% of the planned 300 patients.
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“The proposed changes we submitted to the FDA allow us to thoroughly evaluate the mechanisms through which we hypothesize MultiStem cell treatment can provide benefit to patients suffering an acute ischemic stroke,” Robert W. Mays, PhD, Executive Vice President of Regenerative Medicine, Athersys, added to the statement.1 “This outcome more accurately reflects our belief that MultiStem’s treatment effect extends beyond Day 90 and is better reflected with a Day 365 assessment of functional recovery.”
MultiStemis an allogeneic cell therapy designed to produce therapeutic factors in response to signals of inflammation and tissue damage. It is also being evaluated in the MATRICS-1 clinical trial (NCT04533464) for treatment of hemorrhagic trauma, which recently completed enrollment in the second cohort.2
MATRICS-1 is a phase 1/2 randomized, double-blind, placebo-controlled investigator-initiated study partly supported by Medical Technology Enterprise Consortium in partnership with the Department of Defense and underway at the University of Texas-Houston and the Memorial Hermann Hospital. The second cohort is using cells manufactured under Athersys’ new 3D manufacturing process to be compared against patients treated with 2D-manufactured cells in the first cohort. The trial plans to enroll 156 participants total with enrollment of the third and final cohort expected to begin later in 2023.
“We are pleased to report these enrollment updates as they demonstrate both increasing interest in MultiStem and improved execution by our team and our partners... Athersys’ enthusiasm about MultiStem for the treatment of ischemic stroke has been bolstered by results from completed clinical trials, and we look forward to providing updates on MASTERS-2 after we engage with regulatory authorities during the first quarter of 2023,” Camardo said in an earlier statement.2
