The FDA has issued a Complete Response Letter (CRL) rejecting Capricor Therapeutics’ marketing application for deramiocel, a cell therapy targeting cardiomyopathy in Duchenne muscular dystrophy (DMD) patients. The agency cited insufficient substantial evidence of efficacy and requested additional clinical data. This decision follows significant changes within the FDA’s cell and gene therapy leadership during the product’s regulatory review. The setback resulted in a notable decline in Capricor’s stock price and underscores ongoing challenges in the approval of novel cell-based therapies for rare diseases.