Safety and efficacy of natalizumab in children with multiple sclerosis

Abstract

Objective: To describe the effect of natalizumab in the treatment of subjects with active multiple sclerosis (MS) treated before the age of 18 years. Methods: Nineteen pediatric subjects with MS (mean age 14.6 ± 2.2 years, mean number of attacks 5.2 ± 1.9 during the pretreatment phase of 27.7 ± 19.7 months, median pretreatment Expanded Disability Status Scale score [EDSS] 2.5, range 1.0–5.0) were treated with natalizumab at the dose of 300 mg every 28 days. After treatment initiation, patients were reassessed clinically every month; brain MRI was performed at baseline and every 6 months. Results: Patients received a median number of 15 infusions (range 6–26). A transient reversible worsening of preexisting symptoms occurred in 1 subject during and following the first infusion. All the patients remained relapse-free during the whole follow-up. The median EDSS decreased from 2.5 to 2.0 at the last visit (p < 0.001). EDSS remained stable in 5 cases, decreased by at least 0.5 point in 6 cases, and decreased by at least 1 point in 8 cases. At baseline, the mean number of gadolinium-enhancing lesions was 4.1 (range 1–20). During the follow-up, no gadolinium-enhancing lesions were detected (p = 0.008); 3 patients developed new T2-visible lesions at month 6 scan but the overall number of T2 lesions remained stable during the subsequent follow-up. Transient and mild side effects occurred in 8 patients. Conclusions: Natalizumab was well-tolerated in all subjects. A strong suppression of disease activity was observed in all subjects during the follow-up. Classification of evidence: This study provides Class IV evidence that natalizumab, 300 mg IV once every 28 days, decreased EDSS scores in pediatric patients with MS over a mean treatment period of 15.2 months.