FDA approves vamorolone to treat Duchenne muscular dystrophy

The FDA has approved vamorolone (Agamree; Santhera Pharmaceuticals) to treat Duchenne muscular dystrophy (DMD) in patients aged 2 years and older, according to the federal agency. The oral corticosteroid was approved on October 26, 2023. Catalyst Pharmaceuticals, the US-license holder for vamorolone, plans a commercial launch in the first quarter of 2024.^1,2

DMD, a disorder that causes muscle weakness because of a lack of muscle protein (dystrophin), is a potentially fatal disorder that more commonly affects males.¹ The inherited X-chromosome-linked disease is characterized by inflammation presented at birth or shortly after. The inflammation, which is clinically manifested by progressive muscle weakness and degeneration, can lead to fibrosis of the muscle.²

The FDA approval of vamorolone was based on data from the phase 2b VISION-DMD study (NCT03439670) that featured 3 open-label trials in which vamorolone was administered at 2 to 6 mg / kg per day for a period of up to 48 months. The primary outcome, Time to Stand (TTSTAND) velocity compared to placebo at 24 weeks was met.²

The novel treatment demonstrated comparable efficacy, as data suggest of a reduction in adverse events, most notably for bone health, growth trajectory, and behavior, compared to current standard of care corticosteroids.²

Current available data demonstrates that vamorolone has no restriction of growth and “no negative effects on bone metabolism as demonstrated by normal bone formation and bone resorption serum markers,” according to Santhera.²

The FDA stated that the most common side effects are cushingoid features, psychiatric disorders, weight gain, vomiting, vitamin D deficiency, and weight gain. Vamorolone was granted orphan drug designation by the FDA, which occurs when the federal agency supports the development of a new product to treat or prevent a rare disease.³

The designation qualifies sponsors for tax credits for qualified clinical trials, exemption from user fees, and the potential of 7 years of market exclusivity following FDA approval as incentives. A request for this designation must be submitted to the FDA.³

References:

1. FDA Roundup: October 27, 2023. FDA. Press release. October 27, 2023. Accessed October 20, 2023. https://www.fda.gov/news-events/press-announcements/fda-roundup-october-27-2023

2. Santhera receives US FDA approval of Agamree (vamorolone for the treatment of Duchenne muscular dystrophy. Santhera Pharmaceuticals. Press release. October 27, 2023. Accessed October 30, 2023. Orsanthera.com/assets/files/press-releases/2023-10-27_FDA-approval_e_final.pdf

3. Designating an orphan product: drugs and biological products. FDA. Updated July 8, 2022. Accessed October 30, 2023. https://www.fda.gov/industry/medical-products-rare-diseases-and-conditions/designating-orphan-product-drugs-and-biological-products