This study is a prospective, multicenter, open-label, single-arm effectiveness and safety study in participants with progressive multiple sclerosis (PMS).

Inclusion Criteria:

• Have a definite diagnosis of PMS (as per the revised McDonald 2010 criteria for PPMS or Lublin et al. 2014 criteria for PMS)
• EDSS (Expanded Disability Status Scale) </ =6.5 at screening
• Have a documented evidence of disability progression independent of relapse at any point over the 2 years prior to the screening visit. In case relapse(s) have occurred in the last 2 years, disability progression will have to be considered as independent of relapse activity as per treating physician's judgment
• Fulfill at least one of the 21 criteria assessing the evidence of disability progression independent of relapse activity in the last 2 years using the pre-baseline disability progression rating system checklist
• Have experience of having used a smartphone and connecting a smartphone to Wi-Fi network providers
• For women of childbearing potential: agreement to remain abstinent or use acceptable contraceptive methods during the treatment period and for at least 6 months, or longer if the local label is more stringent after the last dose of study drug

Exclusion Criteria:

• Relapsing-remitting multiple sclerosis (RRMS) at screening
• Inability to complete an MRI
• Gadolinium (Gd) intolerance
• Known presence of other neurological disorders

Exclusions Related to General Health:

• Pregnancy confirmed by positive serum β human chorionic gonadotropin (hCG) measured at screening
• Lactation
• Any concomitant disease that may require chronic treatment of systemic corticosteroids or immunosuppressants during the course of the study
• History or currently active primary or secondary immunodeficiency
• Lack of peripheral venous access
• Significant or uncontrolled somatic disease or any other significant disease that may preclude participant from participating in the study.
• Active infections must be treated and resolved prior to the first infusion of ocrelizumab
• Participants in a severely immunocompromised state until the condition resolves
• Participants with known active malignancies or being actively monitored for recurrence of malignancy
• Participants who have or have had confirmed progressive multifocal leukoencephalopathy (PML)

Exclusions Related to Laboratory Findings:

• Positive screening tests for hepatitis B
• CD4 count <250/μL
• ANC <1.0 × 103/μL
• AST/SGOT or ALT/SGPT ≥3.0 × ULN in combination with either an elevated total bilirubin (>2 X ULN) or clinical jaundice

Exclusions Related to Medications:

• Hypersensitivity to ocrelizumab or to any of its excipients
• Previous treatment with ocrelizumab
• Previous treatment with B-cell targeted therapies (i.e., atacicept, tabalumab, belimumab, ofatumumab, or obinutuzumab). Note: previous treatment with rituximab is allowed as long as the last dose was administered more than 6 months before the ocrelizumab infusion AND if discontinuation was due to adverse events or immunogenicity AND if Bcell levels are above the lower limit of normal (LLN) prior to screening.
• Any previous treatment with alemtuzumab (Campath/Mabcampath/Lemtrada), total body irradiation, or bone marrow transplantation
• Previous treatment with natalizumab where PML has not been excluded according to specific algorithm
• Contraindications to or intolerance of oral or intravenous (IV) corticosteroids, including methylprednisolone administered IV, according to the country label
• Systemic corticosteroid therapy within 4 weeks prior to screening
• All vaccines should be given at least 6 weeks before the first infusion of ocrelizumab, unless the local regulations allow for a shorter interval. Live/live attenuated vaccines should be avoided during treatment and safety follow-up period until B cells are peripherally repleted
• Previous treatment with daclizumab, ozanimod or figolimod in the last 8 weeks
• Previous treatment with siponimod in the last 2 weeks
• Treatment with fampridine/dalfampridine (Fampyra)/Ampyra) or other symptomatic MS treatment unless on stable dose for ≥30 days prior to screening
• Previous treatment with natalizumab in the last 12 weeks.
• Previous treatment with teriflunomide in the last 12 weeks. This washout period can be shortened if an accelerated elimination procedure is implemented before screening visit. One of the following elimination procedures can be used:
• Cholestyramine 8 g administered 3 times daily for a period of at least 7 days (cholestyramine 4 g three times a day can be used, if cholestyramine 8 g three times a day is not well tolerated)
• Alternatively, 50 g of activated powdered charcoal is administered every 12 hours for a period of at least 7 days.
• Previous treatment with azathioprine, cyclophosphamide, mycophenolate mofetil or methotrexate in the last 12 weeks
• Treatment with any investigational agent within 24 weeks of screening (Visit 1) or five half-lives of the investigational drug (whichever is longer) or treatment with any experimental procedures for MS
• Previous treatment with mitoxantrone, cyclosporine or cladribine in the last 96 weeks
• Participants previously treated with teriflunomide within the last two years, unless measured plasma concentrations are less than 0.02 mg/l. If above or not known, an accelerated elimination procedure should be implemented before screening visit

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