The shares of Sarepta Therapeutics Inc. lost more than half their value in after-hours trading Thursday after the company said a drug candidate showed mixed results in a clinical trial.
Sarepta SRPT,
announced that the drug was able to help patients with Duchenne muscular dystrophy produce specific proteins that they typically do not produce because of the disease in the first 12 weeks of treatment. However, the functional changes over a longer period – 48 weeks – were not statistically significant compared to placebo.
“We intend to continue with zeal and urgency to generate the evidence needed to bring SRP-9001 to waiting Duchenne patients around the world,” Chief Executive Doug Ingram said in a press release Thursday afternoon.
Sarepta shares plunged more than 50% following an out-of-hours trading halt while the news was announced and executives held a conference call Thursday. The stock closed on Thursday with a gain of 1.5% at $ 168.95, but traded below $ 80 in the extended session. Sarepta stocks are up nearly 30% in the past year as the S&P 500 index SPX,
has gained 15.8%.