Interleukin 6 inhibition - RA and beyond.

Three years after the approval of the interleukin 6 (IL-6) receptor antibody tocilizumab in the U.S. for the treatment of rheumatoid arthritis, data has continued to accumulate that can help guide its use for this indication. In particular, the structural benefit of therapy, previously shown in Japanese studies, has been confirmed in non-Japanese populations. Additional studies have identified markers, such as high titer rheumatoid factor, that may be associated with greater clinical response to this agent. While registry data with this therapy have not yet become available, more detailed analyses of clinical trial data have helped clarify the risk for certain toxicities, including infection and gastrointestinal perforation. Importantly, data have become available supporting the use of tocilizumab in diseases other than adult RA. Large clinical trials in systemic juvenile inflammatory arthritis have led to the approval of tocilizumab for this indication, and preliminary data suggests benefit in adult onset Still's disease. Finally, there is interest in the potential of IL-6 inhibition in other diseases, although meaningful data has not yet become available.