This open-label, single-arm study will evaluate the efficacy, safety and tolerability of subcutaneously administered tocilizumab in monotherapy and/or in combination with methotrexate and other non-biologic disease modifying anti-rheumatic drug (DMARDs) in participants with active rheumatoid arthritis (RA) who are naïve to tocilizumab. Participants will receive tocilizumab 162 milligram (mg) subcutaneously weekly for 24 weeks. Participants who complete the core study achieving at least a moderate European League Against Rheumatism (EULAR) response at Week 24 may enter the extension phase and receive for a further 28 weeks at the most.