The Food and Drug Administration on Monday approved a controversial drug to treat Duchenne muscular dystrophy, a rare disease that confines boys to wheelchairs and condemn them to an early death.
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The new drug targets a genetic mutation that affects about 13 percent of Duchenne’s patients. Exondys 51 received accelerated approval because the drug could potentially treat a serious disease that now does not have any effective treatments.
The clinical operations will need to confirm that Exondys indeed does more than improve biomarkers in patients, and actually changes patient outcomes. If the trial fails to verify clinical benefit, the FDA may initiate proceedings to withdraw approval of the drug.
Exondys 51 (eteplirsen) addresses the underlying cause of DMD by enabling the production of a functional dystrophin protein, and clinical studies have demonstrated a broadly favourable safety and tolerability profile as well as efficacy for the drug.
Given up for dead just five months ago, Sarepta Therapeutics Inc. has suddenly been reborn as one of the hottest stars in Kendall Square’s biotech constellation.
Sarepta Therapeutics says it may be 60 to 90 days before it begins generating revenue from Exondys 51, so it will still be a bit before we fully understand the commercial opportunity for this drug.
Roger Daltrey, left, of The Who and cofounder of Teen Cancer America, shakes the hand of Buddy Cassidy, 26, of Annandale, Va., who suffers from duchenne muscular dystrophy. It also bolsters faith that the kind of patient lobbying behind Exondys may be able to shift bureaucratic mountains.
The approval letter was penned by Janet Woodcock, director of the FDA’s Center for Drug Evaluation and Research (CDER).
Mainly, opponents of the treatment questioned the drug’s ability to produce the protein dystrophin, needed to keep muscle fibers from degenerating.
“Ultimately, it appears to us that the FDA bowed to external pressure from patient advocates and others who demanded that a safe and potentially efficacious drug be made available”, said Leerink Swann analyst Joseph Schwartz, in a note to investors. In April, Klobuchar and Wicker led a bipartisan letter urging the FDA to use all available resources and authorities to accelerate the process of getting safe and effective treatments to patients diagnosed with DMD.
FDA scientists, including Dr. Ellis Unger, director of the drug evaluations division overseeing the product, appealed Woodcock’s planned decision to an internal disputes board, according to a publicly available summary of the dispute written by FDA Commissioner Robert Califf on September 16. The most common adverse reactions contrast to a placebo group were vomiting (38%) and balance disorder (38%) with contusion, excoriation, arthralgia, rash, catheter site pain, and upper respiratory tract infection also stated more frequently than placebo (≥ 10%). Given the limited number of treatments for the condition, the agency had no option other than to approve it pending further trials.
“The FDA approval of a therapy that treats Duchenne is an event I once never imagined I would witness in Jett’s lifetime”, McSherry said. It occurs in about one out of every 3,600 male infants worldwide. Orphan drug designation provides incentives such as clinical trial tax credits, user fee waiver and eligibility for orphan drug exclusivity to assist and encourage the development of drugs for rare diseases.
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The approval will intensify an ongoing debate about whether or not the FDA’s record clip of approving drugs, particularly for unmet medical needs and rare disorders, over the last several years is a responsible tack for the agency.
