FDA Accepts Applications for Muscular Dystrophy Drug Deflazacort

Treatment wins priority review

New drug applications (NDAs) for the investigational treatment deflazacort (Marathon Pharmaceuticals) have been accepted for filing and granted a priority review designation by the FDA. The NDAs (one for immediate-release tablet formulations and one for an oral suspension formulation) request approval of deflazacort for the treatment of patients with Duchenne muscular dystrophy (DMD), the most common and most severe form of muscular dystrophy.

Priority review status is reserved for drugs that offer significant improvements over existing options or provide a treatment for a condition for which no approved treatment currently exists. The designation shortens the FDA’s review time from 10 months to a goal of six months. 

The NDA filing included data from studies showing that deflazacort improved muscle strength and other functional outcomes in patients with DMD regardless of genetic etiology and, in one of the studies, ambulation status.

Deflazacort is a glucocorticoid with anti-inflammatory and immunosuppressant properties. It is not approved in the United States for any indication. Versions of deflazacort are available in some countries outside the U.S., where it is approved for a number of indications, but not for DMD. If approved, deflazacort will be among the first commercially available treatments indicated for DMD in the U.S. There is no cure for DMD and currently no FDA-approved treatment.

In a pivotal, randomized, double-blind, placebo-controlled and active-comparator study that followed 196 patients with DMD, deflazacort met its primary endpoint of improved muscle strength compared with placebo at 12 weeks. Improvements in muscle strength continued through the end of study at week 52.

Adverse events associated with deflazacort include weight gain, increased appetite, Cushingoid appearance (facial puffiness), unwanted hair growth, skin redness, and headache.

DMD is the most common and most severe form of muscular dystrophy. It affects mainly boys and young men, with an incidence of approximately one in 5,000 live male births. The disease is marked by progressive muscle weakening and wasting, leading to the inability to walk by the teen years or earlier, and to severe respiratory and cardiac complications. Few patients live into their 30s.

Source: Marathon Pharmaceuticals; August 10, 2016.