The U.S. Food and Drug Administration rejected Capricor Therapeutics’ marketing application for deramiocel, an off-the-shelf cell therapy aimed at treating cardiomyopathy linked to Duchenne muscular dystrophy. The agency issued a Complete Response Letter on 11 July stating the filing did not meet the statutory requirement for “substantial evidence of effectiveness” and pointed to outstanding chemistry, manufacturing and controls issues. Capricor’s shares dropped more than 60% following the announcement. Deramiocel would have been the first therapy specifically targeting Duchenne-related heart complications. Capricor said it will seek a Type A meeting with regulators and intends to resubmit the biologics license application in the third quarter, incorporating data from the ongoing Phase 3 HOPE-3 trial of roughly 100 patients. The FDA indicated the review clock will restart upon resubmission. The decision follows weeks of unusual internal turbulence at the agency. In mid-June the FDA placed Nicole Verdun, then head of its Office of Therapeutic Products overseeing cell and gene therapies, on leave after a disagreement with Center for Biologics Evaluation and Research chief Vinay Prasad over whether an external advisory committee should review deramiocel. The panel was first scheduled and later cancelled. The rejection, coupled with leadership changes and a tougher stance on single-arm studies, signals heightened scrutiny of novel cell and gene treatments under Prasad’s tenure. Companies pursuing similar therapies now face greater pressure to generate robust, controlled clinical evidence before approval.