This is a Phase II, randomized, double-blind, placebo-controlled, parallel-group, multicenter study enrolling patients with active rheumatoid arthritis (RA).

Inclusion Criteria:

• Diagnosis of RA according to the 1987 revised ACR Criteria for the Classification of RA for at least 6 months prior to screening
• Positive for rheumatoid factor or anti-cyclic citrullinated peptide (CCP) antibody, or both
• Active disease, defined as: CRP >= 1.0 mg/dL; swollen joint count >= 6 (66 joint count); tender joint count >= 6 (68 joint count)
• Previous inadequate clinical response to at least one disease-modifying anti-rheumatic drug (DMARD) consisting of either methotrexate (MTX) or leflunomide (LFU)
• For patients currently receiving corticosteroids: Treatment at a stable dose during last 4 weeks prior to screening
• For patients currently receiving non-steroidal anti-inflammatory drugs (NSAIDs): Treatment at a stable dose during last 4 weeks prior to screening
• For patients currently receiving sulfasalazine or anti-malarials: Treatment initiated and continued for at least the last 6 months prior to screening and on a stable dose
• For patients of reproductive potential (males and females): Willing to use a highly effective birth control method for the duration of the study according to local guidelines

Exclusion Criteria:

• Pregnant, planning to become pregnant during the study, or breastfeeding
• Clinically significant abnormal laboratory values or abnormal ECG or vital signs
• History of anaphylactic reactions
• Rheumatic autoimmune disease other than RA, or significant systemic involvement secondary to RA (including but not limited to vasculitis, pulmonary fibrosis, or Felty's syndrome), however patients with secondary Sjogren's syndrome are eligible for the study
• History of or current inflammatory joint disease other than RA (e.g., gout, reactive arthritis, psoriatic arthritis, seronegative spondyloarthritis, Lyme disease) or other systemic autoimmune disorder (e.g., systemic lupus erythematosus, inflammatory bowel disease, scleroderma, inflammatory myopathy, mixed connective tissue disease, or other overlap syndrome)
• Current or recent (within 4 weeks prior to screening) infection, including signs, symptoms or serology of any infection, including HIV, hepatitis B or C, tuberculosis
• Administration of a live, attenuated vaccine within 1 month before dosing or anticipation that such a live attenuated vaccine will be required during the study
• Previous treatment with anti-TNF biologics or other biologic agents, including anti-CD20-directed therapy (e.g. rituximab), anti-IL6-directed therapy (e.g. tocilizumab), or T cell-directed therapy (e.g. abatacept)