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 anti-tumour 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 well-defined and manageable safety profile that supports a favourable benefit/risk ratio for patients with RA.