Interleukin 1 receptor antagonist anakinra improves functional status in patients with rheumatoid arthritis

This study evaluated the benefit of anakinra, a human recombinant form of interleukin 1 receptor antagonist, on the functional status of patients with active rheumatoid arthritis (RA) despite taking maximally tolerated doses of methotrexate (MTX).

Patients (n = 419) were randomized to receive, in addition to MTX (15 to 25 mg/wk), placebo or anakinra doses of 0.04, 0.1, 0.4, 1, or 2 mg/kg once daily for 24 weeks. Functional status measured on 8 scales (dressing and grooming, arising, eating, walking, hygiene, reach, grip, and activities) was evaluated at baseline and every 4 weeks with the Health Assessment Questionnaire (HAQ). A weighted sum of the scale scores is the HAQ disability index (HAQ-DI). Primary analysis of the HAQ-DI was based on an omnibus test for a positive dose-response relationship between anakinra treatment and change in HAQ-DI from baseline to week 24.

Patients receiving anakinra experienced rapid and sizeable improvements in their HAQ-DI scores in a dose-related fashion. For patients receiving either of the 2 highest doses of anakinra, improvements in the HAQ-DI occurred by week 4 that were of a magnitude considered clinically important and statistically significantly superior to placebo.

In patients with persistence of RA despite MTX therapy, treatment with anakinra results in a rapid improvement in functional status as measured by the HAQ-DI.