Study to Evaluate the Efficacy and Safety of Dimethyl Fumarate (Tecfidera) and Peginterferon Beta-1a (Plegridy) for the Treatment of Relapsing-Remitting Multiple Sclerosis in Pediatric Participants

A Randomized, Double-Blind, Double-Dummy, Placebo-Controlled, 3-Arm, Parallel Group Study in Pediatric Subjects Aged 10 Through 17 Years to Evaluate the Efficacy and Safety of BG00012 and BIIB017 for the Treatment of Relapsing-Remitting Multiple Sclerosis

The main objective of the study is to evaluate the efficacy of dimethyl fumarate (Tecfidera) and peginterferon beta-1a (Plegridy), both compared with placebo, in pediatric participants with RRMS. The other objectives of this study are to evaluate the safety and tolerability of dimethyl fumarate and peginterferon beta-1a and to assess the effect of dimethyl fumarate and peginterferon beta-1a, both compared with placebo, on additional clinical and radiological measures of disease activity.

Participants will be randomized in a 1:2:2 ratio to receive the double-blind study treatment (Dimethyl Fumarate, Peginterferon Beta-1a, and placebo). Participants experiencing a confirmed relapse or disability progression or high lesion burden on MRI will have the option to discontinue the blinded study treatment and switch to an alternative therapy or open-label BG00012.

Key Inclusion Criteria:

• Must have a diagnosis of RRMS as defined by the revised consensus definition for pediatric MS
• Must have an EDSS score between 0.0 and 5.0.
• Must have a body weight of ≥30 kg
• Must have experienced ≥1 relapse in the 12 months prior to randomization (Day 1), or must have evidence of asymptomatic disease activity seen on MRI in the 6 months prior to randomization, or ≥2 relapses in the 24 months prior to randomization (Day 1). Relapse is defined as the occurrence of a clinical demyelination event regardless of whether the event is a first or subsequent demyelinating event.

Key Exclusion Criteria:

• Participants having primary progressive, secondary progressive, or progressive RMS.
• Disorders mimicking MS, such as other demyelinating disorders, systemic autoimmune disorders, metabolic disorders, and infectious disorders.
• History of clinically significant cardiovascular, pulmonary, GI, hepatic, renal, endocrinologic, hematologic, immunologic, metabolic, dermatologic, growth, developmental, psychiatric (including depression), neurologic (other than MS), and/or other major disease and/or laboratory abnormality indicative thereof, that would preclude participation in a clinical study
• Occurrence of an MS relapse within the 30 days prior to randomization (Day 1) and/or the subject has not stabilized from a previous relapse prior to randomization

NOTE: Other protocol defined Inclusion/Exclusion criteria may apply.