This is a Phase I multicenter study that will be conducted in the United States and Europe.

Inclusion Criteria:

• RA diagnosed according to the American College of Rheumatology (ACR)

Exclusion Criteria:

• Female patients who are pregnant, plan to become pregnant during the study, or are breastfeeding
• Clinically significant abnormal ECG
• History of anaphylactic reactions
• Positive hepatitis C antibody or hepatitis B surface antigen
• Positive serology for human immunodeficiency virus (HIV) by quantitative polymerase chain reaction
• A history of an autoimmune disease other than RA (other than secondary Sjogren syndrome)
• Significant systemic involvement of RA, including vasculitis, pulmonary fibrosis, or Felty syndrome
• Malignancy, or prior malignancy, other than non-melanoma skin cancer, or cervical carcinoma in situ that has been resected
• Recent administration of a live, attenuated vaccine, or anticipation that such a live attenuated vaccine will be required during the study or within 60 days after the last dose
• Concomitant therapy with a biologic agent
• Recent exposure to any investigational agent
• Any current or recent signs or symptoms of infection requiring parenteral antibiotic administration
• Hospitalization for a clinically relevant event within the 4 weeks prior to screening