Vamorolone shared similar efficacy and disease modification as traditional glucocorticoid treatments and demonstrated fewer adverse outcomes with long-term use compared with traditional glucocorticoid therapy in patients with Duchenne muscular dystrophy (DMD), according to the results of a new study published in JAMA Network Open.

The Cooperative International Neuromuscular Research Group conducted a nonrandomized, open-label, controlled, extension trial at 11 US and non-US locations and analyzed the data from July 2020 until November 2021. Investigators assessed clinical outcomes following 30 months of vamorolone therapy in 46 boys with DMD between 4.5 and 7.5 years of age.

Only 41 boys of the 46 who completed the original 6-month dose-finding study completed the 24-month long-term extension study in which researchers elevated the vamorolone dose to either 2.0 mg/kg/d or 6.0 mg/kg/d. Outcome measures included change in time-to-stand velocity (primary outcome), timed function tests, the 6-Minute Walk Test, and the NorthStar Ambulatory Assessment (NSAA).


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Although the time-to-stand velocity decreased from baseline to 30 months after vamorolone therapy (0.206 rises/second vs 0.189 rises/second), the change failed to achieve statistical significance compared with traditional glucocorticoid use.

Additionally, the investigators observed no significant changes in NSAA total score (P =.92), body mass index (P =.58), or the timed function test. This indicated that both vamorolone and traditional glucocorticoids successfully maintained muscle strength and improved motor function in those with DMD.

Moreover, patients taking vamorolone exhibited stable height percentiles while those taking traditional glucocorticoids demonstrated significant growth delays over time. This finding suggested that clinicians in the future may consider vamorolone a more attractive standard-of-care treatment for DMD.

“A randomized double-blind vamorolone study (VBP15-004; NCT03439670) is near completion; results from this study will provide class I evidence for vamorolone efficacy and safety,” the authors concluded.

Reference

Mah JK, Clemens PR, Guglieri M, et al. Efficacy and safety of vamorolone in Duchenne muscular dystrophy: a 30-month nonrandomized controlled open-label extension trial. JAMA Network Open. 2022;5(1):e2144178. doi:10.1001/jamanetworkopen.2021.44178