Treatment of patients with rheumatoid arthritis with the interleukin-1 receptor antagonist anakinra (Kineret®)

New treatment strategies in rheumatoid arthritis are targeted to interfere with critical mediators of inflammation. Proinflammatory cytokines like IL-1beta and TNFalpha play a crucial role in induction and maintenance of synovitis, pannus formation and bone and cartilage destruction. Within a few years, these morphological changes may lead to joint destruction and consecutively to functional impairment. Since April 2002 a recombinant human interleukin-1 receptor antagonist (Anakinra) is available in Germany for treatment of patients with rheumatoid arthritis. Anakinra (Kineret(R)) is approved for therapy in combination with methotrexate and should be applied according to guidelines established by the German Rheumatology Society for the use of biologicals in treatment of patients with rheumatoid arthritis. The approval of anakinra as a new therapeutic is based on data obtained in large multicenter, placebo-controlled, and randomised trials in comparison to placebo. Treatment of Anakinra as monotherapy or in combination with methotrexate lead to significant improvement of signs and symptoms of disease as measured by the ACR 20 (or more) response and was associated with a slower radiographic progression with regard to joint space narrowing and development of erosions. Anakinra showed a favourable safety profile with injection side reactions as the predominant side effect that occurs in 70% of patients usually after 10-12 days of treatment and that are mostly mild to moderate and self-limiting. Patients with previous pneumonia or other risk factors for pulmonary infections such as chronic obstructive lung disease seem to show a slightly increased risk of developing infectious complications of the bronchopulmonary system while being on anakinra and should be monitored appropriately. Combining IL-1ra treatment with the use of anti-TNF agents showed an increased risk of infectious complications in clinical studies and is not recommended at present. Studies are currently assessing the use of anakinra for treatment of other rheumatic diseases like psoriatic arthritis, juvenile arthritis or spondylarthropathy.