BACKGROUND: The efficacy and safety of anakinra, a recombinant human interleukin 
1 (IL1) receptor antagonist used in rheumatoid arthritis, has been documented in 
five randomised controlled studies. However, long term post-marketing efficacy 
data are lacking.
OBJECTIVE: To evaluate the efficacy, safety, and drug survival of anakinra in 
clinical practice.
METHODS: All patients with rheumatoid arthritis who started anakinra in six 
hospitals between May 2002 and February 2004 were included in a two year 
prospective, in part retrospective, cohort study. Efficacy was assessed using 
the 28 joint disease activity score (DAS28) and the EULAR response criteria. 
Safety was evaluated using the common toxicity criteria. Drug survival and 
prognostic factors were analysed using Kaplan-Meier and Cox proportional hazard 
analyses.
RESULTS: After three months, 55% of the patients (n = 146) showed a response 
(43% moderate, 12% good). A subset of patients continuing anakinra after 18 
months had a sustained clinical response compared with patients who switched to 
other disease modifying antirheumatic drug treatment (DAS28 improvement, 2.46 v 
1.79). Drug survival was 78%, 54%, and 14% after three, six, and 24 months, 
respectively. The reason for discontinuation was lack of efficacy in 78% and 
adverse events in 22%. Except for higher drug survival in women (odds ratio = 
0.51, 95% confidence interval, 0.27 to 0.97), no prognostic factors were found. 
Adverse events were reported 206 times in 111 patients, the most common being 
injection site reactions (36%). Serious adverse events occurred in 12% of the 
patients, with one classified as related.
CONCLUSIONS: The short term efficacy and safety profile of anakinra are 
comparable to those found in randomised clinical studies. However, the drug 
survival of anakinra after two years is low, mostly because of lack of efficacy.