This open-label, multi-center, two-arm, uncontrolled and non-randomized study will evaluate the efficacy and safety of RoActemra/Actemra (tocilizumab) in patients with rheumatoid arthritis. Patients will receive 8 mg/kg RoActemra/Actemra intravenously every 4 weeks for 12 weeks and - if adequately responded - for further 12 weeks. Patients, who show an inadequate clinical response after the first 12 weeks to RoActemra/Actemra, will receive 1 g MabThera/Rituxan (rituximab) intravenously at Week 16 and 18. The anticipated time of study treatment is 32 weeks.