Background: Delandistrogene moxeparvovec (Elevidys) is a gene replacement therapy that was initially granted accelerated approval in June 2023. The label was recently expanded to treat both ambulatory and non-ambulatory patients over four years of age. Elevidys safety profile described in clinical trials has been manageable with a predictable time course. However, more serious adverse events can be present including myocarditis and immune mediated myositis.
Objective: To describe the adverse events in a cohort of patients with Duchenne Muscular Dystrophy (DMD) treated with Elevidys in the Neuromuscular Clinic at Children’s Health Dallas.
Methods: IRB approval was obtained. A retrospective chart review was performed, patients treated with Elevidys from July 2023 to December 2024 were included.
Results: Fourteen patients with confirmed DMD diagnosis were treated with Elevidys. Mean age in years at time of treatment was 6.5. The oldest patient was 14 years old and was non ambulatory at time of treatment. Six patients were naïve to steroids, six were on daily and two on weekend steroid regimen prior to gene therapy. All patients were placed on high daily dose steroids as recommended by the label. Two patients were considered high risk based on cardiac status (presence of late gadolinium enhancement on cardiac MRI) and required more frequent monitoring post treatment. One patient had mild myalgias. Eleven patients experienced mild gastrointestinal side effects, the most common were nausea, emesis and decreased appetite. One patient had acute liver injury and one acute myocarditis, both patients were hospitalized and treated with high dose IV steroids.
Conclusions: The most common side effect reported in clinical trials was emesis (58.8%). In our cohort of patients, the adverse effects reported were consistent with those reported in clinical trials. Additional real-world data is required to ascertain the prevalence of potential side effects in a broader patient population.