Sarepta Therapeutics and Roche suffered a major setback after the European Medicines Agency’s Committee for Medicinal Products for Human Use issued a negative opinion on Elevidys, their gene therapy for Duchenne muscular dystrophy. The panel said the study submitted for boys aged three to seven who can still walk failed to show a statistically significant improvement in motor function on the North Star Ambulatory Assessment, and therefore did not support conditional approval. The rejection compounds regulatory pressure already faced by the treatment. Brazil’s health authority Anvisa has temporarily suspended all marketing and distribution of Elevidys, and in the United States the Food and Drug Administration earlier asked Sarepta to halt shipments following two fatal cases of acute liver failure in patients who received the therapy. Roche, which holds commercial rights outside the U.S., said it will engage with the EMA to explore a path forward but acknowledged the decision was a disappointment. Investors reacted swiftly: Sarepta shares fell about 14% in pre-market trading to roughly $11.34, adding to a 6% slide after JPMorgan downgraded the stock to Underweight. The string of regulatory setbacks raises fresh doubts over the commercial prospects of one of the most closely watched gene therapies in neuromuscular disease.