"We are completely shocked at how they decided to review and analyze this data. It just shows that you can take any clinical-trial data and make it look quite dark and cloudy when you apply the wrong statistical analysis plan," said Capricor CEO Linda Marbán.
The reviewers also questioned whether the trial population had DMD-related cardiomyopathy, noting that patients had normal heart-pumping function on average at the outset.
There are currently no FDA-approved therapies specifically for DMD-associated cardiomyopathy, a form of heart disease that commonly develops as the disease progresses.
Agency questions changes to trial analysis
The agency's staff said Capricor changed how it measured the main results after the therapy's late-stage trial ended, calculating arm-function performance as a percentage change instead of the original plan of analyzing scores in a 42-point test.
Measurement of heart function was also changed to ranking patients' results, from monitoring changes in the percentage of blood pumped by the heart with each beat, the reviewers said in their briefing document.
"FDA does not consider the conversion of raw change to percent change and then back to raw change to have been scientifically justified, as it adds complexity and reduces accuracy," the agency's staff said in their briefing document.
Last year, the Food and Drug Administration had declined to approve the therapy and sought additional data after saying the treatment did not meet efficacy requirements.
Capricor said it submitted an updated analysis plan in September 2025 but received no FDA feedback before finalizing and sending a newer version locked in November.
FDA staff said the November revision was not submitted for agency review before the marketing application was filed.
FDA reviewers raise questions ahead of advisory meeting
U.S. FDA staff reviewers raised concerns about the effectiveness data for Capricor Therapeutics' CAPR.O cell therapy for a heart condition related to Duchenne muscular dystrophy, dragging the company's shares 65% lower in early trading.
The briefing documents, released on Monday, mention the effectiveness and risk-benefit profile of the experimental therapy, deramiocel, to be discussed at the FDA's external advisers' meeting on Wednesday.
"The briefing documents raise many more concerns versus what we originally were anticipating, putting Capricor in a tough situation for Wednesday," said Cantor analyst Kristen Kluska.
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