A Phase 3 trial published in The Lancet reports that deramiocel, a donor-derived heart-derived cell therapy, slowed muscle decline in boys and young men with advanced Duchenne muscular dystrophy in the HOPE-3 study. Participants received the therapy via IV every three months for one year, and the company and investigators reported slower deterioration in upper-limb function versus placebo. The paper also describes subgroup signals that may extend to cardiac outcomes, including better heart function preservation among participants with pre-existing heart muscle disease based on available scan assessments. The therapy was generally safe, but allergic-type reactions were more common in the deramiocel arm. The publication strengthens the scientific record behind the program even as it faces regulatory headwinds in the advisory process. Clinicians and investors will be watching how FDA reviewers weigh the primary and key secondary endpoints when deciding on its regulatory submission. For the field, HOPE-3 represents the first Phase 3 study of a donor-cell therapy administered through the bloodstream in advanced DMD, potentially setting a template for future cell-therapy endpoint designs in muscular dystrophies.