Natalizumab in pediatric multiple sclerosis: results of a cohort of 55 cases

Background: Limited information is available on the use of natalizumab (NA) in pediatric multiple sclerosis (ped-MS) patients. Objective: The purpose of this study was to describe the long-term effects of NA in a large cohort of active ped-MS patients. Methods: Patients with definite ped-MS were treated with NA if in the previous year they had experienced at least two relapses or a severe relapse with incomplete recovery while on immunomodulating treatment, or at least two relapses and new magnetic resonance imaging (MRI) lesions regardless of any prior treatment. Results: The study included 55 patients (mean age: 14.4 years, mean number of relapses: 4.4, pre-treatment mean disease duration: 25.5 months). They received a median number of 26 infusions. Three relapses occurred during the follow-up, one female patient continued to deteriorate in cognitive functioning. Mean Expanded Disability Status Scale (EDSS) scores decreased from 2.7 to 1.9 at the last visit (p<0.001). During the follow-up the majority of patients remained free from MRI activity. Transient and mild clinical adverse events occurred in 20 patients. Mild hematological abnormalities occurred in seven patients. Anti-JCV antibodies were detected in 20/51 tested patients. Conclusions: NA was well tolerated in all patients. A strong suppression of disease activity was observed in the majority of patients during the follow-up.