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More than three dozen medical experts are urging the Food and Drug Administration to approve a Sarepta Therapeutics medicine for combating Duchenne muscular dystrophy, a rare disease that causes muscles in boys to stop working and eventually results in death because they can no longer breathe.

In a Feb. 24 letter to the agency, the academics maintain that FDA staffers made several blunders in a so-called briefing document the agency released last January prior to a meeting to review the drug. That meeting was delayed due to a snowstorm and has since been rescheduled for April. In the document, FDA reviewers signaled doubts about whether the drug would pass muster.

But the FDA document “contains some scientifically questionable comparisons, and, in some instances, has errors that may lead to a false perception that there is little evidence that eteplirsen (the name for the Sarepta drug) has any effect at slowing the progression” of the disease, they wrote to Dr. Billy Dunn, who heads the division of neurology products at the agency. The letter began circulating yesterday.


Currently, no treatment has been approved to treat DMD, but efforts by a highly vocal advocacy community — largely driven by parents — have transformed the disease into something of a litmus test for the FDA and its mandate to become more responsive to patients. Agency officials say they are sympathetic, but have signaled that approval standards must be maintained.

In recent months, however, the FDA has rejected two other DMD drugs from BioMarin Pharmaceuticals and PTC Therapeutics, dashing the hopes of many parents that any treatment will become available any time soon and, perhaps, discourage further investment in researching other medicines.


And so, the campaign by the academics may add still more pressure on the agency to endorse the Sarepta treatment. Last month, more than 100 members of Congress — both Republicans and Democrats — wrote the FDA and implored the agency to employ the accelerated approval process for greenlighting medicines that would meet otherwise unmet medical needs.

The academics include experts in pediatrics, neurology, and muscular dystrophy, and claim they have collectively seen more than 5,000 DMD patients. They supported points Sarepta made in an unusual rebuttal to the FDA briefing document, and argued the totality of the Sarepta clinical trial data provides “substantial evidence” that the medicine is effective. And like the lawmakers, they argued for accelerated approval.

We should note that several of the academics have ties to Sarepta – eight are listed as principal investigators for its clinical trials and two serve on its advisory board. In addition, the first two experts to have signed the letter are Carrie Miceli and Dr. Stanley Nelson, who run the Center for Duchenne Muscular Dystrophy at UCLA and have a son with DMD. Several of the academics are also affiliated with the center and sit on the scientific advisory board of CureDuchenne, an advocacy group that raises money to invest in drug makers developing products to combat DMD.

In any event, some Wall Street analysts suggested the letter from the academics could make a difference.

“We believe this is a very significant asset for Sarepta going into next month’s panel,” wrote RW Baird analyst Brian Skorney to investors. “Even the most skeptical person is going to find it hard to argue that a regulator’s interpretation of a data set is more relevant than the interpretation of those with the most experience.”

Similarly, Needham analyst Chad Messer wrote in an investor note that, “assuming the top decision makers at the FDA are not as intractable as the authors of the FDA briefing documents, we believe the letter could help influence the ultimate accelerated approval decision.”

The letter is only four pages long, but goes into substantial detail in castigating the FDA for its analysis of the Sarepta clinical trial data. In particular, the academics were critical of an FDA suggestion to compare the drug with another from a competitor’s clinical trial, since that study enrolled boys with different ages and involved treatment for much less time.

(This story was updated to reflect the ties between some of the academics and the company.)

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