A Study to Assess the Safety and Efficacy of Tocilizumab in Patients With Active Rheumatoid Arthritis

Inclusion Criteria: * adult patients at least 18 years of age with active RA for at least 3 months; * patients of reproductive potential must be using reliable methods of contraception. Exclusion Criteria: * major surgery (including joint surgery) within 8 weeks before entering study or planned major surgery within 6 months after entering study; * treatment with methotrexate (MTX) within 6 months of entering study; * patients who have stopped previous MTX treatment due to toxicity or lack of response; * women who are pregnant or breast-feeding.