This study is to evaluate efficacy of 6 months treatment of tacrolimus in active Rheumatoid Arthritis patients who showed unsuccessful response against methotrexate.

Inclusion Criteria:

• Patients with more than 6 months history of rheumatoid arthritis according to ACR criteria
• Patients who have been treated unsuccessfully to more than single DMARDs including methotrexate at the discretion of investigator
• ESR ≥ 30 mm/h or CRP ≥ 1.0 mg/dL (ESR: Erythrocyte Sedimentation Rate, CRP: C-Reactive Protein)
• Patients are required to have at least 3 of 66 joints assessed as swollen
• Patients are required to have at least 6 of 68 joints assessed as painful with pressure

Exclusion Criteria:

• Pregnant or breast-feeding patients. Patients who plan to bear children or breast-feed during the study and within 6 month after completion of study
• Previous experience of tacrolimus (ointment excluded)
• Renal impairment or serum creatinine > 1.4 mg/dL
• Liver function failure as follows: viral hepatitis, non-viral hepatitis, cirrhosis, SGOT/SGPT > 2x upper limit normal
• Patients with history of pancreatitis, glucose intolerance or complication or who indicates any of the following criteria:Blood glucose level >110mg/dl before the meal and >200mg/dl after the meal HbA1c > 6.4%
• Cardiac disease(ischemic heart disease, treatment-requiring arrhythmia, heart failure)or complications
• Other investigational drug within last 30 days
• Patients who have been treated with infliximab, adalimumab, or leflunomide within 8 weeks of start of the study