Drug Retention Rate and Predictive Factors of Drug Survival for Interleukin-1 Inhibitors in Systemic Juvenile Idiopathic Arthritis

Medical records from sJIA patients treated with anakinra (ANA) and canakinumab (CAN) were retrospectively analyzed from 15 Italian tertiary referral centers.

Seventy seven patients were enrolled for a total of 86 treatment courses. The cumulative retention rate of the IL-1 inhibitors at 12-, 24-, 48- and 60-months of follow-up was 79.9%, 59.5%, 53.5% and 53.5% respectively, without any statistically significant differences between ANA and CAN (p=0.056), and between patients treated in monotherapy compared to the subgroup co-administered with conventional immunosuppressors (p=0.058). On the contrary, significant differences were found between biologic-naive patients and those previously treated with biologic drugs (p=0.038) and when distinguishing according to adverse events (AEs) occurrence (p=0.04). In regression analysis, patients pre-treated with other biologics (HR=3.357 [C.I. 1.341-8.406], p=0.01) and those experiencing AEs (HR=2.970 [C.I. 1.186-7.435], p=0.020) were associated with a higher hazard ratio of IL-1 inhibitors withdrawal. The mean treatment delay was significantly higher among patients discontinuing IL-1 inhibitors (p=0.0002).