Rheumatoid arthritis is the most common inflammatory arthritisaffecting, from 0.5% to 1% of general population worldwide.The underlying pathogenesis of RA is unknown, but key factors ofthe disease process have been identified. Cytokines, interleukin-1,interleukin-6, and tumor necrosis factor, are known to play a substantialrole in joint destruction. Activation of t-cells and B-cells stimulates acascade of events, including cytokine release, which leads to inflammationand joint destruction.Biologics are recommended for use in patients with rheumatoidarthritis who have a suboptimal response or intolerance to traditionaldisease-modifying antirheumatic drugs, such as methotrexate. Althoughbiologics have typically been compared with placebo, with both groupstaking the same dose of methotrexate concomitantly, there have been nolarge randomized controlled trials comparing the biologics to one another.