The main purpose of this study is to assess the bioequivalence of ocrelizumab SC test formulation to the marketed ocrelizumab SC reference formulation in participants with either relapsing multiple sclerosis (RMS) or primary progressive multiple sclerosis (PPMS). The study consists of 2 phases: a controlled phase, where participants in each group will receive one dose of test or reference formulation and a continuation phase, where all participants in both groups will receive ocrelizumab SC test formulation.

Inclusion Criteria:

• Diagnosis of RMS or PPMS according to the revised McDonald 2017 criteria (Thompson et al. 2018) or the most current McDonald criteria at the time of study start
• Expanded Disability Status Scale (EDSS) score, 0-6.5, inclusive, at screening

Exclusion Criteria:

• Participants who have previously received anti-cluster of differentiation (CD) 20s (including ocrelizumab) less than 2 years before screening
• Participants who have previously received anti-CD20s (including ocrelizumab) more than 2 years before screening if one of the following conditions is met: B-cell count is below lower limit of normal (LLN), or the discontinuation of the treatment was due to safety reasons
• 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
• Sensitivity or intolerance to any ingredient (including excipients) of ocrelizumab
• History of severe allergic or anaphylactic reactions to humanized or murine monoclonal antibodies
• 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 participation in the study
• Lack of peripheral venous access
• Previous treatment with cladribine, atacicept, and alemtuzumab
• Any previous treatment with bone marrow transplantation and hematopoietic stem cell transplantation
• Any previous history of transplantation or anti-rejection therapy
• Positive screening tests for active, latent, or inadequately treated hepatitis B virus (HBV)

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