The FDA revised the prescribing information for Sarepta Therapeutics’ Duchenne muscular dystrophy gene therapy Elevidys to include a boxed safety warning and to limit use to ambulatory patients, while requesting postmarketing studies. The agency’s actions respond to evolving safety data and clinician concerns about patient selection and risk management. Regulators and Sarepta continue to debate long‑term monitoring requirements and appropriate surveillance for gene therapy recipients. The FDA’s label change underscores heightened post‑approval scrutiny for in‑vivo gene therapies and an emphasis on real‑world safety data. Clinicians and payers will need to adjust treatment algorithms and monitoring protocols. The decision signals that even after approval, regulators expect rigorous postmarketing evidence generation to refine benefit‑risk profiles for novel genetic medicines.