The FDA revised the label for Sarepta’s Duchenne muscular dystrophy gene therapy Elevidys, adding a boxed warning and narrowing use to ambulatory patients while requesting post‑marketing data. The agency’s actions follow physician concerns about safety and real‑world risk profiles for the AAV vector‑based therapy. BioCentury reports the FDA’s label changes aim to address adverse events and guide prescribing to patients who may benefit most; the agency also asked Sarepta to conduct a post‑marketing study to monitor long‑term outcomes. The decision reflects increased regulator scrutiny of in‑vivo gene therapies and a push for tighter safety monitoring. Clinicians and payers will need to adapt patient selection and monitoring protocols; sponsors of similar in‑vivo programs can expect heightened expectations for post‑approval evidence.