FDA Approves First Corticosteroid for Duchenne Muscular Dystrophy

The FDA approved deflazacort (Emflaza) tablets and oral suspension for the treatment of patients age 5 and older with Duchenne muscular dystrophy (DMD).

Deflazacort is a corticosteroid that decreases inflammation and the activity of the immune system in patients with this rare genetic disorder, which is characterized by muscle deterioration and weakness, according to a press release.

Corticosteroids are used to treat DMD worldwide, but this is the first FDA approval of this class of drug to treat DMD. This is also the first approval of deflazacort in the United States.

DMD is the most prevalent type of muscular dystrophy, and is caused by a lack of dystrophin, which is a protein used to keep muscle cells intact. Patients typically present symptoms between 3 and 5 years, and worsens over time.

DMD typically occurs in patients with a family history of the disease, and primarily affects 1 in 3600 male infants around the world, according to the press release.

Patients with DMD progressively lose their ability to fulfill day-to-day activities, and will require the use of a wheelchair by the time they reach their teens. Over the years, patients can develop heart and respiratory conditions, which causes death by their 20s or 30s.

The effectiveness of deflazacort was explored in a clinical trial that included 196 male children aged 5 to 15. At baseline, all patients presented mutation of the dystrophin gene and muscle weakness before age 5, according to the press release.

After 12 weeks of deflazacort treatment, patients were observed to have improvements in muscle strength, compared with those treated with placebo. Gains in muscle strength were observed through 52 weeks in patients treated with the drug.

In another clinical trial that included 29 male patients, deflazacort treatment was associated with gains in muscle strength. Patients treated with deflazacort were also seen to lose their ability to walk later compared with those treated with placebo, according to the press release.

Adverse events seen with deflazacort are similar to those seen with other corticosteroids, including facial puffiness, weight gain, increased appetite, upper respiratory tract infection, cough, extraordinary daytime urinary frequency, unwanted hair growth, and excessive stomach fat.

Other less common side effects include problems with endocrine function, increased likelihood of infection, high blood pressure, risk of gastrointestinal perforation, skin rashes, behavioral and mood changes, decrease in bone density, and vision problems.

The application was previously granted fast track and priority review designation, as well as orphan drug designation, to address the clinically unmet needs of patients with DMD.

“This is the first treatment approved for a wide range of patients with Duchenne muscular dystrophy,” said Billy Dunn, MD, director of the Division of Neurology Products in the FDA’s Center for Drug Evaluation and Research. “We hope that this treatment option will benefit many patients with DMD."