Objective To assess the efficacy and safety of the IL-1b inhibitor canakinumab in all adults with refractory Still's disease identified from the National Organization For Medicines for off-label drug use. Methods : In a retrospective longitudinal multicenter cohort of 50 patients (median age 39 years) with active Still's disease despite treatment with corticosteroids (n = 11), conventional and synthetic (n = 34) and/or biologic disease modifying anti-rheumatic drugs (n = 30), we assessed the efficacy of canakinumab 150–300 mg administered every 4 (n = 47) or 8 weeks (n = 3) as combination therapy or monotherapy (n = 7) during a median follow-up of 27 (3–84) months. Results Α complete response was initially observed in 78% of patients within 3 months (median), irrespective of age at disease onset. A partial response was evident in 20%. One patient had resistant disease. Treatment de-escalation was attempted in 15 of 39 complete responders and a complete drug discontinuation in 21 patients for 8 months (median). Eleven patients (22%) relapsed during treatment, one during de-escalation process, and 11 after treatment discontinuation. Overall, 9 of 11 relapses were successfully treated with canakinumab treatment intensification or re-introduction. At last visit, 18% of patients were off treatment due to remission and 26% due to disease activity. Canakinumab had a significant corticosteroid sparing effect allowing weaning in 21 of 41 cases. Infections (20%, severe 4%) and leucopenia (6%) led to treatment cessation in one patient. Conclusion High rates of sustained remission were observed in this, largest so far, real-life cohort of adult patients with refractory Still's disease treated with canakinumab.
