Thirty-six doctors, all experts in Duchenne muscular dystrophy, or DMD, have written a letter to the U.S. Food and Drug Administration urging the agency to approve Sarepta Therapeutics' (SRPT) - Get Report experimental therapy eteplirsen.

The lobbying effort seeking to bolster support for eteplirsen and Sarepta -- and counter previously released FDA criticism of the drug -- is ramping up as an advisory committee meeting on April 25 nears.

Last month, 109 members of Congress sent their own letter to the FDA urging the agency to accelerate the approval of a DMD drug, without mentioning eteplirsen by name.

Sarepta shares rose 16% to $20.92 Monday after the scientific letter was released publicly. The letter was dated Feb. 24 and was addressed to Billy Dunn, the director of the FDA's neurology division in charge of the eteplirsen clinical review.

"We suggest that the most scientifically robust way forward and the most ethical choice for the Duchenne community is in the context of an accelerated approval followed by a confirmatory trial," wrote Dr. M. Carrie Miceli and Dr. Stanley Nelson, co-director of the Center for Muscular Dystrophy at UCLA, referring to eteplirsen.

The full letter can be downloaded and read here.

In the letter, Miceli and Nelson rebut some of the criticism leveled against the eteplirsen clinical data by FDA staff when the medical review of the drug was made public in January. The letter also expresses support for updated eteplirsen data submitted by Sarepta to the FDA.

The FDA accepted Sarepta's supplemental eteplirsen data and extended the drug's review period by three months from February to May.

As previously reported

, the FDA's decision to extend the eteplirsen review period could be a signal that the new data satisfy the agency's initial concerns.

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