Introduction: Vamorolone is a novel dissociative steroid recently approved by the FDA in October 2023 for treatment of patients with Duchenne muscular dystrophy (DMD) age 2 years and older, regardless of genetic variants in dystrophin or ambulatory status. Early clinical trials were suggestive of efficacy and a more favorable safety profile with fewer side effects related to linear bone growth and bone turnover as compared to those treated with traditional glucocorticoids. _x000D_
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Methods: Clinical features and treatment response were reviewed retrospectively for 31 patients diagnosed with DMD who were transitioned to vamorolone from alternative glucocorticoid therapy since March 2024. _x000D_
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Results: Patients were ages 3 to 19 years old at time of initiation of vamorolone therapy. All patients were previously on prednisone or deflazacort therapy. 10 out of 31 patients were receiving exon skipping therapy and 4 out of 31 patients had received gene therapy with delandistrogene moxeparvovec at time of initiation of vamorolone therapy. 1 patient undergoing exon skipping therapy reported rapid weight gain trajectory on vamorolone for which he was transitioned back to prior deflazacort therapy. 4 other patients also reported significant weight gain within 3 months of vamorolone initiation for which the dose has been decreased to 4 to 5 mg/kg/day. Most notable, 4 patients in this cohort reported notable progression of weakness within 1 month of vamorolone initiation with treatment at 6 mg/kg/day. These patients did not have clear evidence of adrenal insufficiency. These 4 patients were transitioned back to prednisone or deflazacort therapy. _x000D_
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Conclusion: Data on optimal and safe transition to and from vamorolone for treatment in DMD in combination with other novel therapies is lacking at this time. Long-term efficacy and safety in this cohort remain to be determined.