Long-term efficacy and safety of canakinumab in the treatment of systemic juvenile idiopathic arthritis in Japanese patients: Results from an open-label Phase III study

Objectives The objective of the study was to report the efficacy and safety of canakinumab treatment in Japanese patients with systemic juvenile idiopathic arthritis (sJIA) over a 48-week study period. Methods Patients were administered canakinumab 4 mg/kg (maximum dose 300 mg) every 4 weeks, with no dose adjustments. The key outcome measures included adapted American College of Rheumatology paediatric (aACR pedi) 30/50/70/90/100 response, proportion of patients with inactive disease, and corticosteroid (CS) tapering. Results In total, 16/19 (84.2%) patients received canakinumab for >= 96 weeks reaching end-of-study (EOS) visit without premature discontinuation. Regardless of the level of joint involvement at baseline, high aACR pedi responses were observed throughout the study; at the EOS, aACR pedi 90/100 response rates were 84.2%/63.2%, respectively. The proportion of patients who successfully tapered CSs at EOS was 66.7% (12/18), of which 10 patients were steroid-free. The most common adverse events were infections (238.3 events/100 patient-years). Serious adverse events were observed in 52.6%. The event (n=1) adjudicated as possible macrophage activation syndrome was preceded by sJIA flare. No deaths were reported. Conclusions Canakinumab treatment resulted in a sustained treatment response in sJIA patients over 48 weeks and was associated with CS tapering in majority of patients. No new safety findings were reported.