24 week open-labeled extension study to continue monitoring the same group of patients in the previous MRA230TW phase IIIb trial in order to evaluate the long term efficacy and safety of tocilizumab.

Inclusion Criteria:

• Patients who had completed at least 5 out of the 7 visits scheduled for weeks 2, 4, 8, 12, 16, 20 and 24 in the tocilizumab Phase IIIb study(MRA230TW).
• Patients assigned in the Phase IIIb study(MRA230TW), who had received scheduled dose for at least 16 weeks but still failed to achieve adequate treatment response characterized by ACR20

Exclusion Criteria:

• Patients who have received a major surgery including joint surgery 8 weeks prior to the screening or are scheduled to be operated within 6 months after the enrolment.
• Patients with rheumatoid autoimmune disease other than RA, including but not limited to SLE(system lupus erythematosus), or significant systemic involvement secondary to RA.
• Patients who belong to the Class IV of the ACR classification criteria for functional status of RA. (ACR Amended Criteria for the Classification of Functional Capacity in Rheumatoid Arthritis; Class IV: Largely or wholly incapacitated with patient bedridden or confined to wheel chair, permitting little or no self-care).
• Patients with a history of hypersensitivity to human, humanized or murine monoclonal antibodies or patients with contraindication for them.
• Patients who currently have or have a history of recurrence of bacterial, viral,fungal, or mycobacterial infections or other infectious diseases; tuberculosis(TB),atypical mycobacterial disease, clinically significant granulomatous disease on chest radiograph, hepatitis B, hepatitis C, or herpes zoster and etc. However, a patient with hand & foot fungal infections can participate.