THU0599 Evaluation of efficacy and safety of canakinumab in japanese patients with systemic juvenile idiopathic arthritis in phase iii clinical trial, composed predominantly of patients with prior use of tocilizumab

Background Systemic juvenile idiopathic arthritis (SJIA) is a distinct form of juvenile idiopathic arthritis (JIA), accounting for approximately 4% to 17% of JIA1. In Japan, a higher frequency of SJIA, 41.7% of JIA2 has been reported compared to Europe and United States. Tocilizumab (TCZ) is the only approved biologic for SJIA treatment in Japan. However, some patients (pts) demonstrate persistently high disease activity and/or drug intolerabiliy. Therefore, new treatment options are required. Here, we evaluated the efficacy and safety of canakinumab (CAN), a human anti-interleukin-1s monoclonal antibody, in Japanese SJIA pts. Objectives To report the results of a 28 week (Wk) interim whole analysis of Phase III data (NCT02396212) of CAN, and the subgroup analysis of pts with or without prior use of TCZ. Methods Patients (age ≥2- Results The trial enrolled 19 pts who had insufficient response to prior treatment; the majority (15/19, 78.9%) had received TCZ (table 1). Of the 19 pts, 3 discontinued CAN due to lack of efficacy or adverse events (AE) by Wk28 and 16 completed the assessment of Wk28. All pts (19/19) achieved aACR 30/50/70 at Wk8 (figure 1). Overall, 73.7% (14/19) pts achieved corticosteroid tapering at Wk28 and 2 pts (10.5%) achieved ”steroid free”. Of 15 pts with prior use of TCZ, 12 pts (80.0%) achieved aACR 100 at Wk8 and 11 pts (73.7%) achieved corticosteroid tapering (26.3%, 5/19). Serious AE (SAE) was seen in 41.1% (8/19) pts, and the most frequent SAE was JIA (flare or worsening of SJIA, 21.1%, 4/19). One macrophage activation syndrome (MAS) but no death was reported. Conclusions CAN 4 mg/kg q4w s.c. provided improvement in disease activity and a redution of oral steroid dose in Japanese SJIA pts, including those who were not well-controlled with TCZ. No new safety concerns were reported. References [1] Ravelli A, Martini. Lancet2007; 369(9563):767–78. [2] Takei S, et al. Annual Report on children with chronic refractory diseases from the Japanese Ministry of Health, Labor and Welfare2008;102–13. Disclosure of Interest None declared