FDA Grants Rare Pediatric Designation to Two Drugmakers for DMD Therapies

The FDA has granted rare pediatric disease designation to two investigational Duchenne Muscular Dystrophy therapies — Sarepta Therapeutics’ eteplirsen and BioMarin Pharmaceutical’s drisapersen — the first DMD candidates to win the designation.

Sarepta announced eteplirsen had received the designation last week, two days after BioMarin’s drisapersen. Both drugs are intended for patients with DMD who are amenable to exon 51 skipping treatment, and both already have orphan drug and fast-track status.

Sarepta has been developing eteplirsen with input from advocacy group Parent Project Muscular Dystrophy, the same group that drafted the first-ever patient-initiated guidance for the FDA. That guidance formed the basis of the agency’s June draft guidance on the development of drugs for DMD.

The Cambridge, Mass., drugmaker designed its clinical studies of eteplirsen in accordance with the FDA’s recommendations and is waiting for the agency to sign off before beginning confirmatory trials, a spokesperson said.

Sarepta resubmitted its NDA for eteplirsen on June 26, and the FDA has until Aug. 25 to accept or reject it. The agency initially turned down the NDA last November, saying it needed additional data.

Sarepta is also working with the European Medicines Agency and hopes to submit a marketing authorization application in early 2016, a spokesperson said.

BioMarin’s drisapersen received its rare disease designation on Aug. 19. The drugmaker acquired the therapy with its January purchase of Prosensa and filed an NDA in April, which the FDA accepted in June. Drisapersen is also being reviewed by the EMA.

The trials BioMarin used for the NDA were completed before the FDA’s draft guidance was released, but the company worked closely with patient groups to design them, spokeswoman Debra Charlesworth said.

Companies that win approval of drugs for rare pediatric diseases are eligible for a voucher that can be redeemed for a priority review of an NDA for a different product. The voucher can also be sold or transferred, as was the case when Retrophin sold its voucher to Sanofi for $245 million. — Kellen Owings