The U.S. Food and Drug Administration revised the label for Sarepta’s Duchenne gene therapy Elevidys, adding a boxed safety warning and restricting use to ambulatory patients. The agency also requested a postmarketing study to address emerging safety questions raised by clinicians and regulators. The change reflects ongoing regulatory scrutiny of in‑vivo gene therapies and highlights the FDA’s focus on balancing access with new safety data as gene‑therapy programs expand into broader patient populations.