Anakinra: the first interleukin-1 inhibitor in the treatment of rheumatoid arthritis.

Rheumatoid arthritis is an immunologically mediated inflammation of joints of unknown aetiology and often leads to disability. This inflammatory process may also involve extra-articular connective tissue. New therapeutic approaches have been made by inhibition of proinflammatory cytokines. Interleukin-1 (IL-1) is regarded as one of the most important mediators in the development of synovialitis. In this article, anakinra (Kineret), the first direct antagonist to IL-1, is discussed, in particular the efficacy and safety data from clinical trials. More than 10,000 patients have been treated with anakinra with significant improvement of inflammation and pain; the rate of radiologically visible progressive joint damage was significantly reduced. Among the adverse events, injection site reactions were most frequent, followed by a mild increase in infections. No activation of tuberculosis, as in tumour necrosis factor-alpha antagonist administration, has so far been reported.