Sarepta Therapeutics Inc. shares lost more than half their value in after-hours trading Thursday, after the company said a drug candidate produced mixed results in a clinical study.
announced that the drug managed to help patients with Duchenne muscular dystrophy produce specific proteins that they typically do not produce due to the disease in the first 12 weeks of treatment. The functional changes over a longer time period — 48 weeks — were not statistically significant against a placebo, however.
“We intend to continue to move forward with diligence and urgency to generate the evidence necessary to bring SRP-9001 to waiting Duchenne patients around the world,” Chief Executive Doug Ingram said in a news release Thursday afternoon.
Sarepta shares dove more than 50% following a halt on after-hours trading while the news was announced and executives held a conference call Thursday. The stock closed Thursday with a 1.5% gain at $168.95, but was trading for less than $80 in the extended session. Sarepta shares have gained nearly 30% in the past year, as the S&P 500 index
has gained 15.8%.