Clinical experience with interleukin-1 receptor antagonist in rheumatoid arthritis

Anticytokine therapy, directed at specific biologic mediators of inflammati on and bone erosion, is a significant advance in the treatment of patients with rheumatoid arthritis (RA). Recent clinical trials have examined the ef fect of several interleukins (IL-1, IL-4, IL-10) as well as tumor necrosis factor-alpha in animal models and in patients with RA. Two major studies in volving nearly 1000 patients analyzed the effect of IL-1 receptor antagonis t (IL-1Ra) when used alone, as well as when used in combination with methot rexate. Patients were evaluated at 24 and 48 weeks, using the American Coll ege of Rheumatology 20% (ACR20) response as the principal endpoint. These t rials have demonstrated the safety and efficacy of cytokine inhibitors in p atients with severe, erosive RA. Results of these safety and efficacy analy ses are presented in this article.