The FDA updated the prescribing information for Sarepta Therapeutics’ gene therapy Elevidys (for Duchenne muscular dystrophy), adding stronger myocarditis language and troponin‑I monitoring warnings and narrowing use in certain patient populations. Regulators described observed “acute, serious, and life‑threatening” myocarditis cases and elevated cardiac biomarkers in treated patients. Sarepta faces heightened post‑marketing safety obligations and potential impacts on Elevidys uptake, particularly among non‑ambulatory patients who are now excluded from certain indications. The label change underscores ongoing safety surveillance for in vivo gene therapies and will shape clinical monitoring strategies and risk‑benefit discussions with caregivers and clinicians.