A Study of Ocrelizumab Administered Subcutaneously in Participants With Multiple Sclerosis Who Switch From an Approved Anti-CD20 Therapy (OSSIA)

Inclusion Criteria:

• Diagnosis of RMS or PPMS according to the revised McDonald 2017 criteria
• Documented Expanded Disability Status Scale (EDSS) score of 0-6.5, inclusive, at screening (or within 6 months of screening)
• Participants discontinuing aCD20 therapy for reasons including, but not limited to, physician/participant preference, access to commercial drug (e.g., insurance coverage issues), or other logistical reasons (such as geographical relocation, travel, etc.) are eligible for this study
• Prior treatment with ofatumumab SC, ublituximab-xiiy IV, or ocrelizumab IV aCD20 therapy

Exclusion Criteria:

• Participants who have demonstrated suboptimal response to aCD20 therapy
• Discontinuing aCD20 therapy because of any of the following treatment emergent adverse events (TEAEs): 1) Grade ≥3 severe infusion-related reaction (IRRs) or injection reactions (IRs); 2) Recurrent Grade ≥3 infections, or the need for ≥2 courses of antibiotics in the 12 months prior to screening, if the investigator believes infection is related to therapy
• Participants with contraindication to Gd+ and participants who for any reason cannot tolerate MRI procedure
• Known presence of active, recurrent, or chronic infection (e.g., human immunodeficiency virus [HIV], syphilis, human papillomavirus [HPV], tuberculosis [TB])
• History of confirmed or suspected progressive multifocal leukoencephalopathy (PML)
• Known presence of neurologic disorders that may interfere with the diagnosis of RMS or PPMS
• Any concomitant disease that may require treatment with systemic corticosteroids (e.g., mineralocorticoids and glucocorticoids) or immunosuppressants during the study
• Known allergy or hypersensitivity to ocrelizumab, rHuPH20, or excipients of the OCR SC formulation
• Any previous treatment with bone marrow transplantation and hematopoietic stem cell transplantation
• Treatment with any live-attenuated vaccine within 6 weeks prior to baseline
• Treatment with any experimental procedures for RMS or PPMS (e.g., treatment for chronic cerebrospinal venous insufficiency)
• Previous treatment with cladribine, atacicept, alemtuzumab or mitoxantrone
• Positive hepatitis B virus (HBV) and hepatitis C virus (HCV) antibody test at screening

Other protocol defined inclusion and exclusion criteria may apply.