Duchenne Muscular Dystrophy: Patients speak, FDA listens

FDA approves Exondys — First Treatment for Duchenne Muscular Dystrophy

Score a major victory for the Duchenne boys.

This week, the Food and Drug Administration approved Exondys 51 — the first treatment for Duchenne muscular dystrophy. The rare genetic disorder is the most common type of muscular dystrophy and results in progressive muscle deterioration and weakness.

By approving Exondys 51, the FDA has offered hope to patients with Duchenne muscular dystrophy, who previously had no treatment options.

“Patients with a particular type of Duchenne muscular dystrophy will now have access to an approved treatment for this rare and devastating disease,” said Janet Woodcock, M.D., director of the FDA’s Center for Drug Evaluation and Research. “In rare diseases, new drug development is especially challenging due to the small numbers of people affected by each disease and the lack of medical understanding of many disorders. Accelerated approval makes this drug available to patients based on initial data, but we eagerly await learning more about the efficacy of this drug through a confirmatory clinical trial that the company must conduct after approval.”

As our executive director Terry Wilcox wrote earlier this year, “This treatment on trial before the F.D.A. Advisory Committee proved optimistic to the few boys able to enroll in the small trial, and yet it is only for 13% of Duchenne’s patients. Depending on what statistics you read, that’s less than 3000 boys in the U.S.”

The Long Path to FDA Approval for Duchenne Muscular Dystrophy Treatment

FDA approval was anything but easy.

Exondys 51 was approved under the accelerated approval pathway, a program designed specifically for serious or life-threatening diseases. Created in 2012 under the Food and Drug Administration Safety and Innovation Act (FDASIA), accelerated approval recognizes the challenges in treating rare diseases.

“For rare diseases, like Duchenne – with an unmet medical need, Congress has worked with FDA to provide tools and authorities that allow the agency to use flexibility when reviewing data for an experimental therapy intended to treat an unmet need, and appears safe and potentially efficacious,” explains Christine McSherry, the executive Director of the Jett Foundation.

At first, an FDA panel rejected the treatment due, in part, to the small number of patients in the clinical trial. It turns out the reason Sarepta Theraputic’s main clinical trial only involved 12 boys was that the company lacked the resources to manufacture more when it started out. Sarepta is a small biotech company with three compounds in their pipeline and no drugs on the market.

“The FDA did show a lot of flexibility,” Sarepta CEO Edward Kaye said. “One of the important things that came across is the FDA is very interested in the patient voice. The agency was very concerned about making sure the drug got to patients, and that was a very good thing.”

Credit Janet Woodcock for Leading Internal Effort at FDA

Robert Goldberg, vice president of the Center for Medicine In The Public Interest, explains in a piece at LinkedIn that much of the credit for the FDA approval goes to Janet Woodcock, M.D., director of the FDA’s Center for Drug Evaluation and Research.

“Woodcock stepped in at that meeting to note that too often the FDA focuses on not approving drugs because they are relatively safe and effective but that it often engages in ‘little consideration of another error, which is failing to approve a drug that actually works,’” he writes.

He adds, “Woodcock has been publically involved in taking the FDA’s good intentions about involving patients in the design of clinical trials and in defining study endpoints as well as encouraging scientifically rigorous alternatives to randomized clinical trials that can bring medicines to market faster as well as allow more patients to participate in a study without randomization.”

FDA Approval is Victory for Patient Engagement

Ultimately, the FDA approval is a win for patient engagement.

Patients spoke up, and to its credit, the FDA listened.

“Today is a huge victory for rare disease drug development, for patient input and perseverance, for constructive and educated advocacy, for scientific innovation and integrity, and, most importantly, for Duchenne families,” the Jett Foundation said in a statement on the decision.

“Our voices, our children’s voices, were heard through our advocacy, our unwillingness to stand down, and our irrefutable defense of a safe drug that has the potential to save lives. We are still foot soldiers in this war, there is so much work left to do and so many battles left to win.”

Learn More about Duchenne Muscular Dystrophy

Duchenne is a progressive neuromuscular disorder that causes a loss of motor, pulmonary, and cardiac function, and premature death.

It is the most common lethal pediatric genetic disorder, and it affects every 1 in 3,500 live male births and some females. Duchenne is caused by the body’s inability to create dystrophin, a large protein found in muscle cells. Duchenne has no FDA approved treatment or cure and is 100 percent fatal. Children with Duchenne are born normal and decline over time, usually losing their ability to walk around the age of 12 and succumbing to the disease in their early to mid-twenties.

Learn more about Duchenne muscular dystrophy by visiting the Jett Foundation’s website.

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