A Study to Assess the Effect of Tocilizumab + Methotrexate on Prevention of Structural Joint Damage in Patients With Moderate to Severe Active Rheumatoid Arthritis (RA)

This 3 arm study will compare the safety and efficacy, with respect to a reduction in signs and symptoms and prevention of joint damage, of tocilizumab versus placebo, both in combination with methotrexate (MTX) in patients with moderate to severe active rheumatoid arthritis. Patients will be randomized to receive tocilizumab 4 mg/kg IV, tocilizumab 8 mg/kg IV or placebo IV, every 4 weeks. All patients will also receive methotrexate, 10-25 mg/week. The anticipated time on study treatment is 1-2 years and the target sample size is 500+ individuals. After completion of the 2 year study participants could participate in the optional 3 year open label extension phase (year 3 to 5).