Inclusion Criteria: - Active RA - Documented comorbid condition (diabetes mellitus requiring insulin or oral hypoglycemic agents; chronic pulmonary disease; history of pneumonia in the last year; or recurrent bronchitis, sinusitis or urinary tract infection) - Able to self-inject study drug Exclusion Criteria: - Previous use of anti-tumor necrosis factor (TNF) monoclonal antibody - Receipt of anti-CD4 or diphtheria interleukin-2 fusion protein within the previous 6 months with subsequent abnormal absolute T cell count - Receipt of intra-articular corticosteroids within 2 weeks before screening - Receipt of cyclosporine, thalidomide or azathioprine within 4 weeks before screening - Significant concurrent medical diseases (serious infection; open cutaneous ulcers; current antibiotic treatment; myocardial infarction [MI] within 12 months of screening; angina pectoris; uncontrolled hypertension; cancer; or HIV positive)