Positive results have been reported from a pivotal phase 3 study of deflazacort (Marathon Pharmaceuticals), an investigational glucocorticoid with anti-inflammatory and immunosuppressant properties, in patients with Duchenne muscular dystrophy (DMD). Deflazacort significantly improved muscle strength in DMD patients compared with placebo.
The randomized, double-blind, placebo-controlled, and active-comparator study involved 196 patients with DMD. The patients were randomly assigned to receive deflazacort 0.9 mg/kg per day, deflazacort 1.2 mg/kg per day, prednisone 0.75 mg/kg per day, or placebo for 12 weeks. The study’s primary endpoint was the change in average muscle strength from baseline to week 12 with deflazacort or prednisone compared with placebo, as measured by the Medical Research Council Index.
Deflazacort met the study’s primary endpoint at week 12 compared with placebo (P = 0.0173 and P = 0.0003 for the 0.9 mg/kg per day and 1.2 mg/kg per day doses, respectively). In addition, the results of timed functional tests, a secondary endpoint, showed that patients treated with deflazacort at both dosages experienced significant improvement (P < 0.002) from baseline to week 12 compared with placebo in the ability to perform three tests: the time from lying down to standing; the time to climb four stairs; and the time to run or walk 30 feet.
Muscle strength was assessed in nonambulatory DMD patients receiving deflazacort at dosages of 0.9 mg/kg per day and 1.2 mg/kg per day. Deflazacort 1.2 mg/kg per day reached statistical significance at week 12 compared with placebo (P = 0.04).
The most common adverse events were cushingoid appearance, hirsutism, weight gain, central obesity, and increased appetite.
The findings were presented at the 68th American Academy of Neurology (AAN) annual meeting in Vancouver, Canada.
There is no cure for DMD and currently no FDA-approved treatment. The FDA has granted fast-track status, an orphan drug designation, and a rare pediatric disease designation to deflazacort for patients with DMD. A new drug application for deflazacort is expected to be submitted in May 2016. If approved by the FDA, the drug could be commercially available in the U.S. in early 2017.
DMD is the most common and most severe form of muscular dystrophy, and affects mainly boys and young men. The disease is marked by progressive muscle weakening and wasting, leading ultimately to the inability to walk by the teen years or earlier and severe respiratory and cardiac complications. Few patients live into their 30s.
Deflazacort is an investigational drug not currently approved in the United States. It is available in some countries outside the U.S., where it is approved for a number of uses, but not for DMD.
Source: PR Newswire; April 19, 2016.