Efficacy of biological agents in juvenile idiopathic arthritis: a systematic review using indirect comparisons

Over the past decade, the availability of biological agents for the treatment of juvenile idiopathic arthritis (JIA) has increased substantially. Because direct head-to-head trials comparing these agents are lacking, we indirectly compared their efficacy.

In a systematic review, all available efficacy data from randomised controlled trials performed in JIA with inclusion of biological agents were retrieved. Indirect between-drug comparisons (based on Bucher's method) were conducted only if trials were comparable with regard to design and patients' characteristics related to treatment outcome.

We identified 11 randomised controlled trials. On the basis of the equality of the trials, six trials were grouped into two networks of evidence. Network 1 included withdrawal trials which evaluated etanercept, adalimumab and abatacept in polyarticular course JIA. Indirect comparisons identified no significant differences in short-term efficacy. Network 2 indirectly compared trials with a parallel study design investigating anakinra, tocilizumab and canakinumab in systemic JIA; no differences in comparative efficacy were identified. Although the two networks were constructed on the basis of comparability, small differences in trial design and case mix still existed.

Because of the small number of trials and the observed differences between trials, no definite conclusions could be drawn about the comparative effectiveness of the indirectly compared biological agents. Therefore, for now, the paediatric rheumatologist has to rely on observational data and safety, practical and financial arguments. Comparability of future trials needs to be improved, and head-to-head trials are required to decide on the best biological treatment for JIA.