This study will evaluate the pharmacokinetics, pharmacodynamics, safety, immunogenicity, and radiological and clinical effects of subcutaneous (SC) administration of ocrelizumab compared with the intravenous (IV) infusion of ocrelizumab in patients with either relapsing multiple sclerosis (RMS) or primary progressive multiple sclerosis (PPMS).

Inclusion Criteria:

• Diagnosis of PPMS or RMS according to the revised McDonald 2017 criteria (Thompson et al. 2018)
• EDSS score, 0-6.5, inclusive, at screening
• Neurological stability for ≥30 days prior to both screening and baseline
• Disease duration from onset of MS symptoms of less than 15 years for patients with EDSS score <2.0 at screening
• For females participants, without reproductive potential may be enrolled if post-menopausal, unless receiving a hormonal therapy for menopause or if surgically sterile
• For females of childbearing potential, agreement to remain abstinent or use adequate contraceptive methods

Exclusion Criteria:

• 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 microbials within 8 weeks prior to and during screening or treatment with oral anti microbials within 2 weeks prior to and during screening
• History of confirmed or suspected progressive multifocal leukoencephalopathy (PML)
• History of cancer, including hematologic malignancy and solid tumors, within 10 years of screening
• Immunocompromised state
• Receipt of a live-attenuated vaccine within 6 weeks prior to randomization Influenza vaccination is permitted if the inactivated vaccine formulation is administered
• Inability to complete an MRI or contraindication to gadolinium administration
• Contraindications to mandatory premedications for IRRs, including closed-angle glaucoma for antihistamines
• Known presence of other neurologic disorders
• Any concomitant disease that may require chronic treatment with systemic corticosteroids or immunosuppressants during the course of the study
• Significant, uncontrolled disease, such as cardiovascular, pulmonary, renal, hepatic, endocrine or gastrointestinal, or any other significant disease that may preclude patient from participating in the study
• History of or currently active primary or secondary (non-drug-related) immunodeficiency
• Pregnant or breastfeeding, or intending to become pregnant during the study and 6 or 12 months
• Lack of peripheral venous access
• History of alcohol or other drug abuse within 12 months prior to screening
• Treatment with any investigational agent within 24 weeks prior to screening or 5 half-lives of the investigational drug (whichever is longer), or treatment with any experimental procedure for MS (e.g., treatment for chronic cerebrospinal venous insufficiency)
• Participants who have previously received anti-CD20s if the last treatment was less than 2 years before screening, and/or if B-cell count is below lower limit of normal, and/or the discontinuation of the treatment was due to safety reasons or lack of efficacy
• Previous treatment with cladribine, atacicept, and alemtuzumab
• Previous treatment with fingolimod, siponimod, ponesimod, or ozanimod within 6 weeks of baseline
• Previous treatment with interferons beta (1a or 1b), or glatiramer acetate within 2 weeks of baseline
• Previous treatment with natalizumab within 4.5 months of baseline
• Treatment with mitoxantrone within 2 years prior to baseline visit or evidence of cardiotoxicity following mitoxantrone use or a cumulative lifetime dose of more than 60 mg/m2
• Previous treatment with any other immunomodulatory or immunosuppressive medication not already listed above without appropriate washout as described in the applicable local label.
• If the washout requirements are not described in the applicable local label, then the wash out period must be 5 times the half-life of the medication. The PD effects of the previous medication must also be considered when determining the required time for washout.
• Any previous treatment with bone marrow transplantation and hematopoietic stem cell transplantation
• Any previous history of transplantation or anti-rejection therapy
• Treatment with IV Ig or plasmapheresis within 12 weeks prior to randomization
• Systemic corticosteroid therapy within 4 weeks prior to screening
• Positive screening tests for active, latent, or inadequately treated hepatitis B
• Sensitivity or intolerance to any ingredient (including excipients) of ocrelizumab
• Any additional exclusionary criterion as per ocrelizumab (Ocrevus®) local label, if more stringent than the above