This double-blind, double-dummy study will evaluate the safety and efficacy of ocrelizumab compared with fingolimod in children and adolescents with RRMS aged between 10 and < 18 years over a flexible duration. The double-blind period will last until after the last participant randomized has completed 24 weeks.

This Phase III randomized, double-blind, double-dummy, multicenter study will evaluate the safety and efficacy of ocrelizumab administered by IV infusion every 24 weeks compared with fingolimod taken orally daily, in children and adolescents with RRMS aged between 10 and < 18 years. The study plans to enroll 171 participants in a 1:1 randomization (ocrelizumab:fingolimod), globally. This study consists of a double-blind, double dummy period in which participants will be treated with either active ocrelizumab or active fingolimod for a flexible duration. Participants who complete the double-blind period will be offered the possibility to enter an optional open-label extension (OLE) treatment period of at least 144 weeks with ocrelizumab.

Inclusion Criteria:

• Body weight ≥ 25 kilograms (kg)
• Diagnosis of RRMS in accordance with the International Pediatric Multiple Sclerosis Study Group (IPMSSG) criteria for pediatric Multiple Sclerosis (MS), Version 2012, or McDonald criteria 2017
• Expanded Disability Status Scale (EDSS) at screening: 0-5.5, inclusive
• For all countries except Germany, at least one MS relapse during the previous year or two MS relapses in the previous 2 years or evidence of at least one Gd enhancing lesion on MRI within 6 months

Inclusion Criteria for Optional OLE Period:

-Participants in Group A (ocrelizumab in the double-blind period [DBP]) and Group B (fingolimod in the DBP) who, in the opinion of the investigator, may benefit from switching to ocrelizumab and who have completed the DBP with study treatment (ocrelizumab/fingolimod), may participate in the OLE period

Exclusion Criteria:

• Known presence or suspicion of other neurologic disorders that may mimic MS
• Significant uncontrolled somatic diseases, known active infection or any other significant condition that may preclude participant from participating in the study
• Participants with severe cardiac disease or significant findings on the screening Electrocardiograph (ECG)

Exclusion Criteria for Optional OLE Period:

-Participants who have discontinued the study during the DBP

For eligible studies, qualified researchers may request access to individual patient level clinical data. See Roche's commitment to transparency of clinical study information here: https://go.roche.com/data\_sharing