FDA Approves Emflaza for Duchenne Muscular Dystrophy

First U.S. approval of a corticosteroid for DMD

The FDA has approved deflazacort (Emflaza, Marathon Pharmaceuticals) tablets and oral suspension for the treatment of patients 5 years of age and older with Duchenne muscular dystrophy (DMD), a rare genetic disorder that causes progressive muscle deterioration and weakness. Deflazacort is a corticosteroid that works by reducing both inflammation and the activity of the immune system.

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

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

The adverse events (AEs) associated with deflazacort are similar to those caused by other corticosteroids. The most common AEs include Cushingoid appearance (facial puffiness), weight gain, increased appetite, upper respiratory tract infection, cough, pollakiuria (excessive daytime urination), hirsutism, and central obesity.

Other less-common AEs include problems with endocrine function, increased susceptibility to infection, hypertension, the risk of gastrointestinal perforation, serious skin rashes, behavioral and mood changes, decreased bone density, and vision problems, such as cataracts. Patients receiving immunosuppressive doses of corticosteroids should not be given live or live attenuated vaccines.

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 approximately one of every 3,600 male infants worldwide.

Individuals with DMD progressively lose the ability to perform activities independently and often require the 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.

Source: FDA; February 9, 2017.