Sarepta rockets up as extension study delivers promising results for DMD

It took a few extra months of treatment, but a group of patients in a key Phase IIb study of Sarepta Therapeutics' (formerly AVI) Duchenne muscular dystrophy therapy eteplirsen registered much better walking distance compared to a placebo arm. The data marks a key vindication for CEO Chris Garabedian's gamble on spotlighting the program after a reorganization of the RNA company last fall. And investors cheered the news by igniting a boisterous rally that drove up the stock price by 140%.

Last April the Bothell, WA-based biotech ($SRPT) managed to hit the primary endpoint in the study while failing to impress investors with the results. Data at 24 weeks indicated that eteplirsen achieved what it aimed at: Raising the level of dystrophin in boys afflicted with DMD through its exon-skipping technology. But there was no improvement in walking distance, a key measure for prospective treatments of DMD, and its stock price plunged.

A dozen boys were recruited for the study. Eteplirsen-treated patients who received a 50 milligram dose demonstrated a decline of 8.7 meters in distance walked from baseline, Sarepta reports today, while patients who received placebo with delayed-eteplirsen treatment showed a decline of 78 meters from baseline. The 69.3 meter benefit was statistically significant.

"The magnitude of this clinical benefit is an unprecedented treatment effect in DMD. This result represents a major advance in the pursuit of a disease modifying treatment for this severe, progressive and life-threatening disease," said principal investigator Jerry Mendell in a statement. "The 6-minute walk test results with eteplirsen, combined with its safety profile to date, make eteplirsen the most promising advance to treat the underlying cause of muscular dystrophy I've seen in my more than 30 years in the field."

Just a few days ago Sarepta also reported positive animal data for its experimental therapy for Marburg virus. A non-human primate study demonstrated a significantly higher rate of survival among NHPs treated with AVI-7288 compared to the placebo-treated group when treatment was administered up to 96-hours post infection. 

- here's the press release on eteplirsen
- get the release on the Marburg virus study

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