Novel Corticosteroid Approved for Rare Disease

Vamorolone (Agamree), a novel corticosteroid treatment, won FDA approval to treat Duchenne muscular dystrophy (DMD) in patients ages 2 years and older, Catalyst Pharmaceuticals announced Thursday.

The dissociative steroidal anti-inflammatory therapy showed similar efficacy to traditional corticosteroids in treating Duchenne with fewer negative downstream effects related to bone health and growth trajectory.

“Corticosteroids have been a first line treatment for DMD for many years but their utility has always been limited by the side effect profile, which includes weight gain, short stature, and decreased bone density, among others,” Sharon Hesterlee, PhD, chief research officer of the Muscular Dystrophy Association (MDA), said in a news release.

Duchenne muscular dystrophy is a rare, progressive genetic muscle disease stemming from a lack of dystrophin, which results in muscle degeneration and weakness. Symptoms often emerge between ages 2 and 3. The disease primarily affects boys. Over time, it becomes fatal as lung and heart function are disrupted.

The FDA decision was based on data from the pivotal phase IIb VISION-DMD study, plus safety information from three open-label studies. In these trials, vamorolone was administered at doses ranging from 2 to 6 mg/kg/day for up to 48 months.

In VISION-DMD, time to stand from supine velocity was significantly greater in boys receiving vamorolone 6 mg/kg compared with placebo over 24 weeks (least squares mean velocity 0.05 vs -0.01 m/s, P=0.002).

Clinically meaningful changes from baseline were also seen in the 6-minute walk test of 42 m for vamorolone 6 mg/kg versus placebo (P=0.003). Time to run/walk 10 meters at 24 weeks was also increased from baseline by 0.24 m/s (P=0.002). The relative efficacy of prednisone and vamorolone 6 mg/kg was similar for motor outcomes.

The most commonly reported adverse events associated with vamorolone in VISION-DMD were cushingoid features, vomiting, and vitamin D deficiency, Catalyst noted. Adverse events were generally mild to moderate in severity.

Vamorolone’s research and development was largely funded by patient advocacy groups and non-profit groups like the MDA.

“MDA is extremely proud to have been involved with vamorolone since its inception,” Hesterlee said. “It was one of the earliest investments to be made by our venture philanthropy arm and we are gratified to see that paying off in the form of a viable new therapy for Duchenne patients and the community.”

Vamorolone is expected to be available in the first quarter of 2024, Catalyst said.