A phase 3 clinical trial published in The Lancet reports that deramiocel slowed muscle decline in boys and young men with advanced Duchenne muscular dystrophy, with signals also reported for heart-function preservation in participants with baseline heart disease. The HOPE-3 study randomized 106 patients aged 10–22 to deramiocel or placebo every three months for one year. After one year, deramiocel-treated patients showed slower decline in arm function compared with placebo, including about a 54% slower overall arm movement decline and about a 65% slower elbow movement decline. Among participants with suitable heart scans, heart function was better preserved, and a smaller subset analysis linked deramiocel to less spread of heart scarring. The trial reported no deaths and a generally tolerable safety profile, although allergic-type reactions were more common with deramiocel (42% vs 15%). The mixed regulatory reaction—publication-level efficacy versus adcomm skepticism—now puts the focus on how specific analytic definitions and endpoint handling will be adjudicated by regulators.