New biologics for rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic inflammatory arthritis with many systemic manifestations. Several monoclonal antibodies targeting different components of the immune systems have been licensed for treatment of RA. Inflammatory cytokines such as interleukin-6 (IL-6) are found abundantly in the blood and the joints. The biologic effect of IL-6 on leukocyte, osteoclast, hepatocytes and bone marrow may mediate the articular and systemic inflammation in RA. Recently, an anti-IL-6 receptor monoclonal antibody, tocilizumab, has been licensed for the treatment as monotherapy or in combination with methotrexate of moderate to severe RA, when disease modifying anti-rheumatic drugs or antitumour necrosis factors (TNF) have failed. It improves symptoms and signs as well as reducing joint damage. Tocilizumab monotherapy has been shown to be superior to methotrexate. Its side-effects include infections, decrease in neutrophils, and increases in lipid and liver transaminases. Overall, tocilizumab has a welldefined and manageable safety profile that supports a favourable benefit/risk ratio for patients with RA.