May 15 (Reuters) - Shares of Sarepta Therapeutics (SRPT.O) soared 29% premarket on Monday as a backing by the U.S. health regulator's advisers increased the certainty of an accelerated approval for the company's gene therapy for a muscle-wasting genetic disorder. Eight of the 14 advisers to the Food and Drug Administration late Friday voted that the company had enough data to support an accelerated approval for its gene therapy for Duchenne muscular dystrophy (DMD). The vote came after FDA staff had earlier last week voiced concerns that the data from the company's mid-stage trial lacked "unambiguous evidence" about benefits from the therapy. TD Cowen analyst Ritu Baral expects an approval for the therapy, especially considering the FDA leadership's interest in promoting biomarker-based accelerated approvals for gene therapies. The FDA, often follows the advice of its expert advisers but is not obligated to do so, is slated to make a decision on accelerated approval by May 29.

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