Sarepta's mega-orphan Duchenne's drug faces more roadblocks
- Sarepta Therapeutics has been developing eteplirsen for the treatment of Duchenne's, a form of muscular dystrophy caused by a genetic abnormality in the exon 51 gene. Without intervention, patients are in wheelchairs by adolescence.
- Sarepta had hoped to file by the end of this year and gain approval by early 2015, but the FDA has requested more information, including more data on a wider selection of patients—meaning that a new clinical trial needs to be initiated.
- Sarepta shares were down 35% on the news and have been hovering at that level since the FDA made its announcement on Monday.
Last year, Sarepta was flying high when data on its phase IIb study, which included just 12 patients, came back positive. However, the FDA has continually had challenges with the size of the clinical trial population, citing concerns about reproducibility.
The phase IIb data showed that eteplirsen helped patients walk better—and there was even a petition initiated by advocates demanding that the FDA allow Sarepta to move forward. However, in addition to the concerns over the tiny sample size, the FDA also has some issues with the trial methodology. The agency specifically wants Sarepta to enroll 60 to 80 patients in a new trial to confirm the results.