This open-label, international multi-center extension study WA18695 was designed to assess the long term safety of tocilizumab in patients who had moderate to severe active rheumatoid arthritis (RA). Patients enrolled in the WA18695 study had previously received treatment in the 24-week, placebo-controlled, Phase III Study WA17822. Eligible patients were assigned to treatment with 8 mg/kg tocilizumab every 4 weeks for a maximum of 5 years.