Duchenne Muscular Dystrophy Update: FDA Weighs Its Options

muscular dystrophy
muscular dystrophy
The DMD space is becoming increasingly crowded as the FDA works to identify a drug worth approving.

The race to approval of a first-of-its-kind drug to treat Duchenne muscular dystrophy (DMD) just got more crowded.

This week, Marathon Pharmaceuticals announced that it submitted a New Drug Application (NDA) to the US FDA for deflazacort, which was previously granted Fast Track status, Orphan Drug designation, and Rare Pediatric Disease designation for the treatment of DMD.

The DMD space has seen an influx of NDAs over the last year as several pharmaceutical companies have tried (and some failed) to break open the treatment of DMD, the most common and severe form of muscular dystrophy which currently has no FDA-approved treatment and no cure.

After a lukewarm review in November, the FDA officially denied the NDA for BioMarin Pharmaceutical’s drisapersen, intended for the treatment of DMD amendable to exon 51 skipping. Late last month, BioMarin announced that it would abandon development of drisapersen and related experimental drugs BMN 044, BMN 045, and BMN 053, indicating that it would work on taking a “next-generation” approach to developing new drugs for the disease.

Perhaps a more promising fate is intended for Sarepta, whose drug eteplirsen is also meant to treat DMD in patients with mutations amendable to exon 51 skipping. After an FDA panel failed to recommend eteplirsen for approval in April, the FDA has extended its decision deadline twice. Most recently, the FDA requested additional data on dystrophin, a key biomarker of efficacy, as it attempts to identify at least one measure that could justify the drug’s approval.

Complicating the situation is the immense, vocal support from the DMD community, who has tried to exert their influence to no avail. While several patients and caregivers provided testimony during the panel review about eteplirsen’s positive effects on their condition, the FDA has struggled to see past Sarepta’s extremely thin data set.

Marathon is hoping for a more clear path to approval.

Different than drisapersen and eteplirsen, Marathon’s deflazacort is a glucocorticoid with anti-inflammatory and immunosuppressant properties intended to improve muscle strength and other functional outcomes in patients with DMD regardless of genetic etiology. The drug is currently approved abroad, but not in the US, for the treatment of several other indications, not DMD.

In an interview with Neurology Advisor, Tim Cunniff, Pharm D, executive vice president of Research and Development at Marathon, recognized the difficulty of developing drugs for rare diseases, but assured us that Marathon has worked closely with the FDA to ensure that its clinical trials ticked all of the boxes.