Comparative Study (Double-Blind) of MRA for Rheumatoid Arthritis (RA)

Inclusion criteria * Diagnosis of RA based on the 1987 classification criteria of the American College of Rheumatology (ACR) * Disease duration of 6 months or more * Treated with 8 mg/week of MTX for at least 8 weeks immediately preceding enrollment, and continued on this treatment up to initiation of the study drug * Active disease at enrollment (less than 2 weeks before initiating treatment with a study drug), Which is defined as having at least 6 tender and 6 swollen joints among 49 and 46 joints stipulated by the Japanese Rheumatism Foundation's Drug Evaluation Committee and ESR at least 30 mm/hr and CRP not less than 1.0 mg/dL Exclusion criteria * Assessed as having Class IV Steinbrocker functional activity in the 4 weeks preceding treatment with the study drug * Treated with infliximab, etanercept or leflunomide in the 12 weeks preceding treatment with the study drug * Received any of the following therapies in the 2 weeks preceding initiation of treatment with the study drug. 1. Administration of any DMARD or immunosuppressant other than MTX 2. Administration of corticosteroids exceeding 10 mg/day as prednisolone 3. Dose escalation or initiation of corticosteroids * Received any of the following therapies in the 4 weeks preceding treatment with the study drug 1. Plasma exchange therapy 2. Surgical treatment (operation, etc.)