All patients enrolled must have an incomplete response to methotrexate at a dosage of at least 12.5 mg/week and a maximum of 15 mg/week orally for a minimum of 6 weeks. They should not have been on higher methotrexate doses than 15 mg/week in the last year prior to study entry. No other disease modifying antirheumatic drugs will be allowed while on study. Patients on DMARDS other than MTX will have DMARDs withdrawn at least 2 weeks prior to trial initiation. Patients are allowed to take prescription doses of FDA approved non-steroidal anti-inflammatory drugs including selective Cox-2 inhibitors. Patients enrolling should be on stable NSAID doses for at least 4 weeks.