New Drug Approved for Rare Disease Despite Lack of Data

The Food and Drug Administration has just approved a new medication for a rare disease, but the approval is controversial.

Duchenne Muscular Dystrophy:

Duchenne muscular dystrophy is a muscle wasting condition that frequently leads to muscle weakness, degeneration and paralysis. Until recently, most victims died before their early 20s.

The drug that the FDA approved is eteplirsen and will be sold under the brand name Exondys 51. This drug is intended for boys with a specific genetic mutation that affects only about 13 percent of those with Duchenne muscular dystrophy. (The mutation affects exon 51, hence the name.) Thus, it is for an unusual variant of a rare disease.

The drug had fast track approval because there are no other accepted treatments for this condition. But because there are so few people with the condition, the usual randomized, placebo-controlled studies were not done.

What Happens Next?

The manufacturer will be required to conduct a post-marketing trial to show the drug really works to make patients’ lives better. Many of the boys and young men affected by this condition are in wheelchairs, and their testimonies at the FDA hearing were apparently effective. There will be a cost, though: As an orphan drug for a rare disease, the anticipated price is breathtaking: $300,000 after discounts.

Did the FDA Follow Its Own Rules?

Drug approval without randomized controlled trials is highly unusual. The FDA’s advisory committee did not recommend approval, because it did not believe the data the company (Sarepta Therapeutics) presented were compelling. FDA’s lead reviewer criticized the data the company presented and left the agency. The acting chief scientist has also objected to the decision. But the head of FDA’s Center for Drug Evaluation and Research, Dr. Janet Woodcock, overruled the scientists for this approval.