 - Stable doses of nonsteroidal anti-inflammatory drugs NSAIDs and oral corticosteroids less than or equal to 10 mgday of prednisone or equivalent for 4 weeks prior to randomization. Exclusion Criteria: - Pregnant or breast-feeding women - Any uncontrolled, clinically significant systemic disease - Has total white cell count less than 3.5 x 109L, a neutrophils count less than 2.0 x 109L, platelet count less than 125 x 109L or hemoglobin Hgb less than 8.0 gdL at screening - Abnormal liver function tests ASTALT greater than or equal to 1.5 x the upper limit of normal at screening - Serum creatinine greater than 1.5 x the upper limit of normal at screening - Subject recall of having tetanus toxoid or diphtheria vaccination less than 10 years prior to randomization - Has never received a primary tetanus vaccination - Any other vaccination within 12 weeks of randomization - Disease-modifying antirheumatic drugs DMARDs other than methotrexate - Biologics to treat RA within the previous 8 weeks of screening e.g., etanercept, infliximab - Subjects were treated with anakinra within 4 weeks prior to randomization 