Shares of Capricor Therapeutics plunged nearly 70% on Monday following the release of FDA briefing documents that cast serious doubt on the company’s cell therapy treatment, deramiocel. The steep decline came after the FDA reviewers highlighted multiple concerns regarding the reliability and validity of the clinical trial data for this therapy aimed at treating cardiomyopathy in patients with Duchenne muscular dystrophy (DMD).
FDA Questions Changes in Trial Data Analysis
The controversy centers on Capricor's decision to alter how trial results were measured after the HOPE-3 study had concluded. Initially, the primary endpoint focused on raw scores from a 42-point arm function test. However, Capricor switched to reporting percentage changes, a move the FDA staff described as unjustified scientifically. They argued that converting raw data to percentages and then back added unnecessary complexity and compromised accuracy.
Similarly, measurements of heart function shifted mid-study. Rather than tracking left ventricular ejection fraction changes as originally planned, the company adopted a ranking system for patient outcomes. This raised further questions about the consistency and robustness of the trial’s methodology.
Doubts About Therapy’s Impact and Patient Selection
The FDA also expressed skepticism about whether sufficient quantities of deramiocel, which is derived from donor heart cells, actually reached the heart to exert a therapeutic effect. Reviewers flagged the intravenous delivery method as potentially inadequate for targeting cardiac tissue effectively.
Another critical point was the makeup of the trial population itself. Patients enrolled reportedly had near-normal heart-pumping function at the start, casting doubt on whether they truly exhibited DMD-associated cardiomyopathy. This issue complicates the interpretation of the trial's effectiveness results.
Deramiocel’s regulatory journey has been challenging. The earlier phase 2 HOPE-2 study failed to show meaningful improvements in skeletal or cardiac function, leading to a Complete Response Letter from the FDA that cited insufficient evidence of effectiveness and an unfavorable benefit-risk profile.
No FDA-approved treatments currently address cardiomyopathy specifically caused by DMD. Existing therapies, such as Sarepta Therapeutics’ gene therapy Elevidys and other exon-skipping drugs, target the genetic root of DMD rather than its cardiac complications.
Upcoming Advisory Committee Review
The Cellular, Tissue, and Gene Therapies Advisory Committee is set to convene on Wednesday, July 29, to review the HOPE-3 study data and advise whether it provides substantial evidence supporting deramiocel’s efficacy. Investors are watching closely, as this meeting could determine the drug's future and Capricor's stock trajectory.
Capricor’s stock had already lost about 40% in early trading Monday before the FDA documents were made public, with the session's sell-off accelerating afterward. The company faces an uphill battle to convince regulators after these critical findings.
This material is for informational purposes only and does not constitute financial advice.
