[Humanized anti-human IL-6 receptor antibody, tocilizumab].

Interleukin-6 (IL-6) is a multifunctional cytokine that regulates immune response and inflammatory reaction. IL-6 has been shown to play pathological roles in the autoimmune reaction, inflammation, and joint destruction in rheumatoid arthritis, and, therefore, an agent blocking IL-6 actions can be a therapeutics of the disease. Tocilizumab is a humanized anti-human IL-6 receptor antibody designed using genetic engineering technology and the first therapeutic monoclonal antibody developed in Japan. Tocilizumab specifically blocks IL-6 actions and ameliorates the diseases with IL-6 overproduction. It has been clinically developed for rheumatoid arthritis and shown to be effective not only for improving signs and symptoms but also for preventing joint destruction of the disease. In this chapter, immunopharmacology and clinical utility of tocilizumab in rheumatoid arthritis is addressed.