June 23 (Reuters) - Sarepta Therapeutics shares (SRPT.O) slumped 11% on Friday as some analysts voiced concerns that upcoming confirmatory trial data for its gene therapy to treat Duchenne muscular dystrophy (DMD) may not be enough to secure approval for expanded use. The U.S. health regulator had on Thursday granted Sarepta's Elevidys therapy accelerated approval to treat DMD patients aged between 4 and 5 years who can walk, contrary to the company's application for all patients who can walk. Sarepta's gene therapy is the first of its kind for DMD, an inherited progressive muscle-wasting disorder that almost always affects young boys. Elevidys, a one-time treatment, is expected to change the way that DMD patients are treated as current therapies require regular use. William Blair's Tim Lugo called the treatment "transformational for Duchenne's patients" and "a significant opportunity for Sarepta".

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Persons: Sarepta's, Gavin Clark, Gartner, William Blair's Tim Lugo, Leroy Leo, Khushi, Devika Organizations: Sarepta Therapeutics, Food and Drug, BioMarin Pharmaceuticals, Thomson Locations: U.S, Bengaluru