This study will evaluate the safety, tolerability, and descriptive efficacy of BIIB017 in pediatric participants with relapsing-remitting multiple sclerosis (RRMS) and to assess the pharmacokinetics (PK) of BIIB017 in pediatric participants with RRMS in Part 1. In Part 2, the study will evaluate the long-term safety of BIIB017 and further describe safety and the long-term multiple sclerosis (MS) outcomes after BIIB017 treatment in participants who completed the study treatment at Week 96 in Part 1 of the study.
An Open-Label, Randomized, Multicenter, Active-Controlled, Parallel-Group Study to Evaluate the Safety, Tolerability, and Efficacy of BIIB017 in Pediatric Subjects Aged 10 to Less Than 18 Years for the Treatment of Relapsing-Remitting Multiple Sclerosis, With Optional Open-Label Extension