2017 USFDA New Drug Apporval: Emflaza tablets to treat Duchenne muscular dystrophy

The US Food and Drug Administration has approved Emflaza (deflazacort) tablets and oral suspension to treat patients age 5 years and older with Duchenne muscular dystrophy (DMD), a rare genetic disorder that causes progressive muscle deterioration and weakness. Emflaza is a corticosteroid that works by decreasing inflammation and reducing the activity of the immune system.

Corticosteroids are commonly used to treat DMD across the world. This is the first FDA approval of any corticosteroid to treat DMD and the first approval of deflazacort for any use in the United States.

DMD is the most common type of muscular dystrophy. DMD is caused by an absence of dystrophin, a protein that helps keep muscle cells intact. The first symptoms are usually seen between 3 and 5 years of age and worsen over time. The disease often occurs in people without a known family history of the condition and primarily affects boys, but in rare cases it can affect girls. DMD occurs in about one of every 3,600 male infants worldwide.

People with DMD progressively lose the ability to perform activities independently and often require use of a wheelchair by their early teens. As the disease progresses, life-threatening heart and respiratory conditions can occur. Patients typically succumb to the disease in their 20s or 30s; however, disease severity and life expectancy vary.

The effectiveness of deflazacort was shown in a clinical study of 196 male patients who were 5 to 15 years old at the beginning of the trial with documented mutation of the dystrophin gene and onset of weakness before age 5. At week 12, patients taking deflazacort had improvements in a clinical assessment of muscle strength across a number of muscles compared to those taking a placebo. An overall stability in average muscle strength was maintained through the end of study at week 52 in the deflazacort-treated patients. In another trial with 29 male patients that lasted 104 weeks, deflazacort demonstrated a numerical advantage over placebo on an assessment of average muscle strength. In addition, although not statistically controlled for multiple comparisons, patients on deflazacort appeared to lose the ability to walk later than those treated with placebo.

The FDA granted this application fast track designation and priority review. The drug also received orphan drug designation, which provides incentives to assist and encourage the development of drugs for rare diseases.

The sponsor is receiving a rare pediatric disease priority review voucher under a program intended to encourage development of new drugs and biologics for the prevention and treatment of rare pediatric diseases. A voucher can be redeemed by a sponsor at a later date to receive priority review of a subsequent marketing application for a different product. This is the ninth rare pediatric disease priority review voucher issued by the FDA since the program began.

Emflaza is marketed by Marathon Pharmaceuticals of Northbrook, Illinois.