Sarepta Therapeutics (NASDAQ:SRPT)gained 70% in August and has seen another 30% increase in September. This run can be attributed to Sarepta's potentially game-changing drug for muscular dystrophy, currently in phase 2 trials. Early reports have been positive, with a significantly slower decline in function and an increase in muscle fibers. While the drug won't undo damage, it could greatly improve the outlook for sufferers.

October will see the release of 48-week data, and if it substantiates the 36-week data, expect this stock's run to continue. Watch the following video for Fool.com analyst David Williamson's full report.

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