Results from a phase 2 clinical trial showed the drug vamorolone had a consistent safety profile in boys with Duchenne muscular dystrophy (DMD) and did not negatively affect growth, according to results published recently in the Journal of Neurology.
Boys who had previously taken standard corticosteroids even experienced catch-up growth after switching to the medication, suggesting it may help address one of the major long-term side effects of traditional steroid treatment.
Corticosteroids such as prednisone or deflazacort are commonly used to slow muscle damage in DMD, but long-term use can cause serious side effects including growth suppression, bone problems and hormone disturbances. Vamorolone is designed to activate beneficial anti-inflammatory pathways similar to steroids while reducing some of these unwanted effects.
The VBP15-006 trial enrolled 34 boys aged 7 to younger than 18 years. Twelve participants had never taken corticosteroids while 22 had previously received them and switched to vamorolone. Participants received either 2 mg/kg/day or 6 mg/kg/day for 12 weeks. All completed the study and entered an expanded access program in Canada, where most continued treatment for a median of about 1.3 years among steroid-naive participants and 1.7 years among those previously treated with steroids.
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“The data suggest no negative effect of vamorolone on growth (i.e., height) in 7- to < 18-year-old CS [corticosteroid]-untreated and previously CS-treated boys with DMD, and a potential recovery of bone health parameters related to previous CS treatment,” explaiend the study’s authors.
Growth outcomes were encouraging. Boys who had not previously used corticosteroids maintained stable height during treatment. In contrast, those who had experienced growth delays after years of steroid therapy showed measurable recovery.
Among 14 participants with available data, height scores improved over time, with some adolescents gaining more than 8 centimeters within 12 months. Blood markers related to bone health also increased substantially, suggesting recovery of normal bone turnover after switching therapies.
Weight changes varied. In the steroid-naive group receiving 6 mg/kg/day, weight increased by a median of 2.25 kilograms over the initial 12-week study period, and about 55% of participants later experienced notable increases in body mass index during long-term follow-up. However, most participants who had previously used corticosteroids maintained relatively stable weight during treatment.
Most side effects were mild. The most common treatment-emergent adverse events involved musculoskeletal symptoms, gastrointestinal complaints or nervous system symptoms. Some participants developed reduced morning cortisol levels, indicating adrenal suppression, and two boys who switched from deflazacort to the lower 2 mg/kg/day dose developed generalized weakness consistent with adrenal insufficiency. Researchers noted that switching to the higher 6 mg/kg/day dose appeared to reduce this risk.
For patients and families, these findings suggest that vamorolone may offer a promising alternative to traditional steroids for DMD. While additional studies are needed, the drug may help preserve the benefits of steroid treatment while reducing some of the growth and bone complications that often affect boys living with the disease.
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