GlaxoSmithKline’s (NYSE:GSK) investigational treatment for Duchenne muscular dystrophy has failed help patients walk better in a phase III clinical trial.
Duchenne muscular dystrophy has no cure. The rare neuromuscular disease affects an estimated one in 3,500 boys. In the failed phase III study, boys on the experimental treatment drisapersen failed to show statistically significant results in a six minute walking distance test compared to those on a placebo.
“We appreciate that these results will be disappointing for boys with DMD and their families. We would like to sincerely thank all those who participated in the study for their commitment,” Carlo Russo, Senior Vice President, Head of GSK Rare Diseases Research & Development said in a statement. “We are committed to evaluating the outcome of this study in the context of the overall development programme with experts in the field, and we expect such evaluation to help inform our next steps for drisapersen.”
GSK licensed drisapersen from Dutch pharma company Prosensa (NASDAQ:RNA) in 2009. Drisapersen has been granted orphan drug status in Europe, the United States and Japan. The designation eases some of the drug approval requirements and also includes tax breaks and marketing exclusivity as incentives to pharmas to develop treatments for rare medical conditions.
But the results call into question the future of the drug, as the partners said they will conduct a full evaluation of the benefit-to-risk profile across all studies that will be completed by the end of 2013.
Before today’s announcement, analysts predicted sales of $350 million for the drug in 2020, according to the average of three estimates compiled by Bloomberg.
Results from a separate late-stage study are expected late next year, and successful results combined with positive data from a mid-stage data could outweigh the results released today, Joseph Schwartz, a Boston-based analyst at Leerink Swann & Co., said in a report to investors.
“The Demand III safety data do not seem significant enough to bar drisapersen from obtaining regulatory approval,” Schwartz said.
Prosensa sold shares in June in an initial public offering at $13 each. The company had a market value of $840.1 million based on yesterday’s closing share price of $24. Prosensa dropped 70 percent to $7.16 as of 10 a.m. in New York with trading volume 45 times the three-month daily average.
GSK shares were trading at $50.61, up 34 cents from Thursday’s closing price.
Sarepta Therapeutics Inc. (NASDAQ:SRPT), which is developing a competing drug, rose as much as 9 percent and was trading 0.8 percent higher at $38.44.
(Bloomberg News contributed to this report)
