- Prior treatment with 1-3 disease-modifying anti-rheumatic drugs (DMARDs) - Patients should have failed at least 1 DMARD but should not be deemed "refractory to all therapies". Patients should be on a current treatment with methotrexate ≤ 25 mg/week and with the current dose stable for at least 3 months. All patients will take folic acid 1 mg daily, or 5 mg weekly post MTX dose, to minimize toxicity, according to local guidelines. In addition to methotrexate, patients may be on either a stable dose of non-steroidal anti-inflammatory drugs (NSAIDs) and/or a stable dose of oral corticosteroids (prednisone or equivalent ≤ 10 mg daily) for at least 4 weeks prior to randomization. Patients who failed any DMARDs will be allowed.