Background Anakinra (r-metHuIL-1ra) has been shown to be an effective therapy for Rheumatoid Arthritis patients since it improves the signs and symptoms of disease, as measured by ACR criteria. To better characterise this response, we have analysed data from two large, placebo controlled studies of anakinra, given as either monotherapy (MONO) or in combination with methotrexate (MTX).

Methods To assess the ACR20 response over the time course of the studies, we evaluated the proportion of patients who had a sustained ACR20 response (Sus Resp), defined as at least four ACR20 responses by week 24, with at least one of the ACR20 responses occurring at either week 12 or 24.

Results Patients receiving anakinra doses >1 mg/kg were 2–3 times more likely than placebo patients to achieve a sustained ACR. The sustained response for both studies was statistically significant. We also evaluated the rapidity of response to anakinra at these doses (> 1 mg/kg). At least 50% of the subjects responding to anakinra achieved an ACR20 response on or before week 4 for either study.

Conclusion In conclusion, treatment of RA patients with anakinra appears to produce a durable response with a quick onset of action. These factors support the use of anakinra as an effective therapy for rheumatoid arthritis.