FDA panel votes against Duchenne muscular dystrophy drug

Although the drug was successful with 12 patients in the small study, the agency said too little data and the lack of a control group for comparison is a problem.

By Stephen Feller

WASHINGTON, April 26 (UPI) -- A U.S. Food and Drug Administration panel voted against approval for eteplirsen, a drug that has showed promise with Duchenne muscular dystrophy patients in small trials, despite parents and children flying from as far as England to encourage the panel's approval.

Eteplirsen has been shown to prolong the ability of boys with the disease to walk long beyond the time they'd be expected to do so, but the panel voted against the drug because a clinical trial included just 12 patients and no control group.


DMD is caused by an absence of the the protein dystrophin, which keeps muscle cells intact, and worsens more quickly than other forms of MD, often occurring in people without a known family history of it, according to the Muscular Dystrophy Association. About 13 percent of MD patients have DMD, which can be seen around age 5 or 6, if not younger.


DMD patients lose the ability to walk and generally end up in a wheelchair -- and the drug has been shown to prolong the ability of patients to walk hundreds of yards farther than patients not on the drug following long-term treatment.

The comparison was based on historical data from patients from Italy and Belgium matched to patients in the trial, however, which FDA officials said is not good enough, the New York Times reports.

FDA officials opened the meeting with discussion of approving drugs that are not as safe as thought being just as a big a risk as holding back a drug that can save lives. Dr. Billy Dunn, director of agency's division of neurology products, pointed out the FDA requires "substantial evidence" when approving drugs.

"These words are not vague words to be defined according to whim or fashion," Dunn said. "Anecdote and emotion do not change the data with which we are confronted, no matter the attendance."

The panel's votes against approval, and against considering data presented to it sufficient for approval, were based on a 12-person study and four years of follow-up with patients, tracking progress. Data from the study was then compared to the historical control group.


Sarepta Therapeutics' eteplirsen is the second drug for DMD to be shot down by the FDA this year because of clinical trials that do not meet its standards after it said no to drisapersen in January with similar concerns about the lack of a placebo group to measure results against.

When it turned down the application for drisapersen for the same reason, doctors involved with studies of the drug said it was difficult, and borderline unethical, to enroll patients in a study who think they may be helped by a promising drug only for them not to receive it.

The agency's view is that effects of drugs must be measurable when being considered for approval, hence the need for control groups, but panel members pointed to other faults in the study, such as the lack of data on the participants' ability to open food, feed themselves or move their limbs -- all of which would show benefits of treatment with the drug.

Advocates and parents point to the success of eteplirsen with patients as reason enough for the FDA to approve the drug. "It's time to listen to the real experts," said Austin LeClaire, a DMD patient who has gained greater use of his arms since being treated with the drug.


So many parents and patients showed up for the hearing it had to be moved to another conference room and ran for nearly 12 hours as presentations and anecdotal evidence were presented in the hope of convincing the panel to approve the drug.

"FDA, please don't let me die early," said 15-year-old Billy Ellsworth, who is in the drug trial, according to the Washington Post. Ellsworth was shown in video to finish the Pittsburgh marathon and break into a jog toward the end, which he and his doctors credit to eteplirsen.

The FDA is not bound to follow the votes of its advisory committees, and is scheduled to complete its review on May 26. Sarepta said in a press release it would continue working with the agency with expectations that approval is on the horizon despite the panel's decision.

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