A Study of Ocrelizumab in Participants With Moderate to Severe Rheumatoid Arthritis (RA)

Inclusion Criteria: * Moderate to severe RA for at least 6 months * Positive serum rheumatoid factor (\>/= 20 international units per milliliter) * Current treatment with RA on an outpatient basis * Treatment failure with one disease modifying anti-rheumatic drug (DMARD) or biologic, but have not failed more than six of these agents including methotrexate * Current treatment with methotrexate for at least 12 weeks, at a stable dose * Use of highly effective contraception. Exclusion Criteria: * Rheumatic autoimmune disease or inflammatory joint disease, other than RA * Concurrent treatment with any disease-modifying anti-rheumatic drug (DMARD) (other than methotrexate) or any anti-tumor necrosis factor (TNF) -alfa or other biologic therapy * Treatment with any other investigational drug within 4 weeks of screening * Previous treatment with cell-depleting therapies, IV gamma-globulin, intra-articular or parenteral corticosteroids, and receipt of live/attenuated vaccine prior to screening * Previous treatment with rituximab or any other anti-cluster of differentiation 20 (CD20) agent * History of severe allergic or anaphylactic reactions to humanized monoclonal antibodies * Known active bacterial, viral or fungal infections * History of active tuberculosis and primary or secondary immunodeficiency * History of concomitant diseases such as cardiovascular disease, nervous system, pulmonary disease, renal, hepatic, endocrine or gastrointestinal disorders * Pregnancy or lactation.