PTC Therapeutics said it will stop pursuing FDA approval for Translarna (ataluren) after regulators indicated the submitted data are unlikely to meet the agency’s threshold for substantial evidence of effectiveness. The company’s decision follows a prior negative decision in Europe and reflects unresolved differences with the FDA over trial interpretation. Translarna has been under development for nonsense‑mutation Duchenne muscular dystrophy for nearly two decades. PTC’s withdrawal underscores regulatory challenges for long‑running rare‑disease programs when new analyses or regulator expectations shift; the move will reshape the company’s regulatory strategy and investor expectations.