A Study to Evaluate Pharmacokinetics, Safety, Tolerability, Immunogenicity and Pharmacodynamic Effects of Subcutaneous Ocrelizumab Administration in Children and Adolescents With Relapsing-remitting Multiple Sclerosis (RRMS)

Prior treatment

• Participants who are positive for aquaporin 4 (AQP4) or myelin oligodendrocyte glycoprotein (MOG) antibody are not eligible to participate in the study
• Any known or suspected active infection at screening or baseline (except nailbed infections), or any major episode of infection requiring hospitalization or treatment with IV anti-infective agents within 4 weeks prior to baseline visit or oral anti-infective agents within 2 weeks prior to baseline visit
• Contraindications to mandatory premedications (i.e., corticosteroids and histamines), including closed-angle glaucoma for antihistamines
• Participants who have previously received treatment with B cell-targeted therapies, including ocrelizumab
• Any previous treatment with cyclophosphamide, alemtuzumab, anti-CD4, cladribine, mitoxantrone, daclizumab, laquinimod, total body irradiation, or bone marrow transplantation
• Treatment with any investigational agent within 24 weeks of screening or 5 half-lives, whichever is longer (or longer if indicated by the PD action of the drug)

Other illness

• Any known presence or suspicion of other neurologic disorders that may mimic multiple sclerosis (MS)
• History or known presence of recurrent or chronic infection (e.g., human immunodeficiency virus \[HIV\], syphilis, tuberculosis \[TB\])
• Contraindications against SC injections or other conditions not suitable for SC injections, e.g., extremely thin SC fat layer
• History of a severe allergic or anaphylactic reaction to humanized or murine monoclonal antibody or known hypersensitivity to any component of ocrelizumab solution

• Children and adolescents from 10 years to less than 18 years of age, at the time of baseline visit
• Body weight ≥25 kg
• Diagnosis of RRMS in accordance with the International Pediatric Multiple Sclerosis Study Group (IPMSSG) criteria for pediatric MS, Version 2012, or McDonald criteria 2017 or 2024
• Neurologic stability for at least 30 days prior to screening, and between screening and baseline
• Expanded Disability Status Scale (EDSS) score, 0-5.5, at screening
• Must have received all childhood required vaccinations as per local/national recommendations for childhood vaccination against infectious diseases