The extension study WA18695 was an open-label, international multi-center study in patients with moderate to severe active rheumatoid arthritis (RA) who had completed treatment in the 24 weeks placebo-controlled Phase III study WA17822. Patients entering WA17822 had an inadequate response to methotrexate (MTX), and, during WA17822, patients had received treatment with intravenous infusions of tocilizumab 4 mg/kg, 8 mg/kg, or placebo every 4 weeks with background MTX therapy.