The study will evaluate the physical impact of MS from participant's perspective, provide continued access to ocrelizumab and assess the safety and tolerability of ocrelizumab.

From Protocol Version 6 onwards, treatment within this study will be limited to the currently approved doses of ocrelizumab, 600 milligrams (mg), intravenous (IV) infusion or 920 mg, subcutaneous (SC) injection.

Inclusion Criteria:

• Participants who were on ongoing ocrelizumab treatment on one of the following parent-studies [Studies MN39159/CONSONANCE (NCT03523858), BN42082/MUSETTE (NCT04544436), BN42083/GAVOTTE (NCT04548999), BN44083/GLOBEAM, MN43978/CONSONANCE Ext., WA40404/O'HAND (NCT04035005), MN43964/OLERO (NCT05269004), GN41791/FENTREPID (NCT04544449), BP46016/MINTAKA, CN41144/OCARINA I-SC (NCT03972306), CN42097/OCARINA II-SC (NCT05232825)] at the time of roll-over and who do not have access to the ocrelizumab treatment locally
• The first dose of study treatment in this extension study will be received no earlier than 5 months after the last treatment in the parent study
• Negative urine pregnancy test within 24 hours to first dose administered on MN45053 study treatment in participants of childbearing potential

Exclusion Criteria:

• Study treatment is commercially marketed in the participant's country for the participant-specific disease and is reasonably accessible to the participant
• Study treatment is available via Post Trial Access Program (PTAP) in the participant's country and is accessible to the participant
• Permanent premature discontinuation of study treatment for any reason during the parent study or during the time between last treatment in the parent study and the first dose of study treatment in this extension study (if applicable)
• Any condition that, in the opinion of the investigator, would interfere with the interpretation of participant safety or place the participant at high risk for treatment-related complications
• Concurrent participation in any therapeutic clinical trial (other than the parent study)
• Immunocompromised state
• Known active malignancy or are being actively monitored for recurrence of malignancy
• Known presence of other neurological disorders

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