Anakinra as a new therapeutic option in rheumatoid arthritis: clinical results and perspectives.

Interleukin-1 receptor antagonist (IL-1Ra) is a member of the IL-1 gene family, which blocks IL-1-mediated signal transduction. In rheumatoid arthritis (RA), recombinant human IL-1Ra (anakinra) has been evaluated in 5 randomized, placebo-controlled clinical trials. In the European monotherapy study, 43% of patients receiving 150 mg/day anakinra achieved a 20% response according to the American College of Rheumatology criteria (ACR 20), compared to 27% in the placebo group. In the methotrexate combination therapy study, 42% of the patients receiving 1 mg/kg/day anakinra achieved an ACR20 response, 24% an ACR50 response, and 10% an ACR70 response. In each study, clinically meaningful improvements in the Health Assessment Questionnaire scores were observed. The Economic Resource Survey was employed in the European monotherapy study to evaluate patient and caregiver days of missed work or domestic activity in successive 4-week periods. There were rapid gains in the number of days at work or domestic activity in the treated patients, and the increases in productivity were dose-related. The mean change in the total modified Sharp score of patients who completed treatment with anakinra was significantly less than in the patients who received placebo. Anakinra, a new biologic approach to the treatment of RA, results in significant improvements in the signs and symptoms, has beneficial effects on functional status, and on the rate of progressive structural joint damage.