The US Food and Drug Administration (FDA) has approved Emflaza (deflazacort) tablets and oral suspension to treat patients with Duchenne muscular dystrophy (DMD).

The rare genetic disorder DMD causes progressive muscle deterioration and weakness.

Emflaza is marketed by Marathon Pharmaceuticals, is a corticosteroid and works by decreasing inflammation and reducing the immune system activity.

FDA Center for Drug Evaluation and research neurology products division director Billy Dunn said: “This is the first treatment approved for a wide range of patients with Duchenne muscular dystrophy.

“We hope that this treatment option will benefit many patients with DMD.”

DMD is the most common type of muscular dystrophy and occurs in patients aged five years and older due to an absence of a protein dystrophin that helps keep muscle cells intact.

The disease primarily affects boys, but in rare cases it can affect girls and its first symptoms are usually seen between three and five years of age.

People with DMD progressively cannot perform activities independently and life-threatening heart and respiratory conditions can occur as the disease progresses.

“We hope that this treatment option will benefit many patients with DMD.”

The effectiveness of deflazacort was shown in a clinical study, which involved 196 male patients at the beginning of the trial, with documented mutation of the dystrophin gene and onset of weakness before age five.

During week 12, patients taking the drug showed improvements in a clinical assessment of muscle strength across various muscles compared to those taking a placebo.

By the end of study at week 52 in the deflazacort-treated patients, an overall stability in average muscle strength was maintained.

The side effects caused by Emflaza are facial puffiness, weight gain, increased appetite, upper respiratory tract infection, cough, extraordinary daytime urinary frequency, unwanted hair growth and excessive fat around the stomach.

Image: Histopathology of gastrocnemius muscle from a patient who died of pseudohypertrophic muscular dystrophy, Duchenne type. Photo: courtesy of Dr. Edwin P. Ewing, Jr.