Experience of one UK site presenting a closer examination of safety and efficacy of Anakinra (Kineret^®) in systemic juvenile idiopathic arthritis

Background

It has been postulated by Pascual and others that Anakinra works only early in systemic JIA (sJIA) and mainly on systemic features. This paper specifically examines the interval between the age of onset and time of starting Anakinra for responders and non-responders, and considers those with active systemic features versus persistent arthritis and their response to Anakinra.

Methods

10 patients (3–17 yrs) with sJIA were enrolled onto a 12 week study at our institution. All patients fulfilled the ILAR classification for sJIA. Out of the 10 patients, 9 had failed anti-TNF. All patients received Anakinra at 2 mg/kg/day subcutaneously with their current therapy, except anti-TNF. Responders met Definition of Improvement (DOI) criteria by >30% improvement in at least 3 of the six JIA core set criteria with no more than 1 criteria worsening by >30% as well as their serum SAA/CRP returning to normal. Systemic features were documented.

Results

Of 10 subjects, 8 completed 12 weeks, 1 dropped out due to lack of efficacy and 1 due to non-compliance. Duration of JIA before starting Anakinra was 1–9 yrs, responders have median duration of 2 yrs of JIA and non-responders median duration of 6.5 yrs. The non-responders had no systemic features at the start of Anakinra, whilst 3 out of 4 responders had fever at initiation of treatment and improved in all.

Conclusion

Out of the 8 patients, the 4 responders started Anakinra a median of two years into their sJIA. This group's persistent systemic feature also improved. These findings support the hypothesis by Pascual.