The U.S. Food and Drug Administration (FDA) is extending its review of deramiocel, an experimental cell therapy for Duchenne muscular dystrophy (DMD) as it reviews additional data.
Capricor Therapeutics, the company developing deramiocel, said it amended its application seeking FDA approval to include new long-term data from the Phase 3 HOPE-3 clinical trial (NCT05126758) and additional statistical analyses. Capricor also said it refined the proposed indication for deramiocel, focusing on the therapy’s impact on upper arm function.
The FDA set a new decision date of Nov. 22; a decision was originally expected by Aug. 22.
“We appreciate the FDA’s continued engagement and look forward to working constructively with the agency as it completes its review,” Linda Marbán, PhD, CEO of Capricor, said in a company press release.
DMD is a genetic disease in which muscles accumulate damage over time. Deramiocel uses immature heart cells called cardiosphere-derived cells, which are thought to dampen inflammation and scarring via the release of signaling molecules.
“In a progressive disease where function, once lost, cannot be recovered, we believe preservation of upper limb function has the potential to translate into meaningful differences in patients’ independence and daily lives,” Marbán said. “That impact reinforces the urgency of our work and our commitment to bringing Deramiocel to the Duchenne community as soon as possible.”
New studies, new data
Capricor has been developing deramiocel to improve mobility and heart function in people with DMD. The company initially applied for FDA approval of deramiocel based on data from the Phase 2 HOPE-2 clinical trial (NCT03406780) and its open-label extension (NCT04428476). Results from these early trials indicated that deramiocel improved measures of arm and heart function, but the studies included fewer than two dozen people with DMD, and in 2025 the FDA declined the application saying more data were needed.
Capricor resubmitted its application based on data from the larger Phase 3 trial HOPE-3, which involved more than 100 people with DMD who either were predicted to be unable to walk in two years or were already unable to walk. The trial’s main goal was to show that deramiocel led to better outcomes than placebo on the Performance of the Upper Limb test, version 2 (PUL 2.0), a standardized measure of arm and hand function.
According to Capricor, HOPE-3 met its goal, with deramiocel leading to significantly better PUL 2.0 scores than the placebo. Published results also showed that the therapy met a key second goal of improving left ventricular ejection fraction (LVEF), a measure of how well the heart pumps blood to the body.
The FDA disputed these claims, saying Capricor altered its statistical analysis plan and that, under the original plan, neither PUL 2.0 nor LVEF showed significant improvements with deramiocel relative to the placebo. Capricor has maintained that the study met its main goal.
“HOPE-3 met its primary endpoint, demonstrating a statistically significant benefit in upper limb function,” Marbán said.
The FDA convened an advisory committee meeting in which independent experts were asked to vote on whether the available evidence supports deramiocel as an effective treatment for heart disease in DMD. A few weeks ago, the council voted no.
As part of ongoing discussions with the FDA following that meeting, Capricor submitted an amendment that includes two years of data from the HOPE-3 open-label extension, in which all patients were treated with deramiocel and monitored for long-term outcomes. Since the FDA has classified these new data as a major amendment, the agency extended its review to allow time to analyze the new information.
“With an additional year of follow-up from HOPE-3, we now have one of the most extensive clinical datasets evaluating upper limb function in Duchenne,” Marbán said. “We believe the additional open-label data and further analyses included in the amendment strengthen the evidence supporting a refined proposed indication.”
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