Canakinumab delivers rapid, durable benefits in systemic juvenile idiopathic arthritis

Treatment with canakinumab produces improvements in systemic juvenile idiopathic arthritis (sJIA), which occur shortly after initiation and last up to 6 months, according to the results of an open‐label, active treatment extension study.

The 2-year, single-arm study enrolled 123 active sJIA patients (aged 2 to <20 years), of whom 70 presented with fever, who initiated open‐label canakinumab (4mg/kg every 4 weeks [q4w]) administered subcutaneously. After 2 months of treatment, the patients were allowed to taper glucocorticoids as guided by the protocol. After 6 months, canakinumab was tapered from 4 mg/kg to 2 mg/kg q4w in glucocorticoid-free patients.

Researchers measured efficacy using the adapted JIA American College of Rheumatology (aJIA‐ACR) criteria, Juvenile Arthritis Disease Activity Score (JADAS), and clinically inactive disease (CID)/clinical remission on medication (CR).

The median follow-up duration was 1.8 years, with 84 patients (68.3 percent) completing the study.  Treatment induced aJIA‐ACR 50/70/90/100 responses as early as day 15, and the proportion of patients who achieved the respective improvements was similar in the fever (60.0 percent/48.6 percent/37.1 percent/24.3 percent) and no-fever subgroups (67.3 percent/48.1 percent/34.6 percent/19.2 percent). These proportions increased thereafter. 

By month 6, 17 patients (24.3 percent) achieved CR_JADAS and 26 (37.1 percent) achieved CR_ACR in the fever subgroup. The corresponding number of patients in the no-fever subgroup was 9 (17.3 percent) and 12 (23.1 percent). Median time to onset of CR_JADAS and CR_ACR was 57 and 30 days, respectively, in the former subgroup, and 58 and 142 days, respectively, in the latter.

An aJIA‐ACR50 response by day 15 strongly predicted CR_JADAS (odds ratio [OR], 13, 95 percent confidence interval [CI], 4–42; p<0.0001) or glucocorticoid discontinuation (OR, 19, 95 percent CI, 3–114; p=0.002).

Out of the 71 (57.7 percent) patients who were on glucocorticoids at study entry, 27 (38.0 percent) achieved freedom and 21 (29.6 percent) reached a dose of <0.2 mg/kg/day, with no difference between the fever and no‐fever subgroups. Thirteen patients (10.6 percent) tolerated a sustained canakinumab dose reduction to 2 mg/kg q4w.

No new safety concerns emerged.