The Use of Canakinumab, a Novel IL-1β Long-Acting Inhibitor, in Refractory Adult-Onset Still's Disease

ObjectivesWe describe the successful treatment of adult-onset Still's disease (AOSD) with canakinumab, a novel anti-interleukin (IL)-1β, long-acting, monoclonal antibody, on patients refractory to anakinra and rilonacept. In many cases the expected positive therapeutic effect of short-acting IL-1 inhibitors is transient or completely absent, leading to our hypothesis that their short half-life may be associated with incomplete IL-1 blockade, given the cyclic nature of the disease.MethodsWe report 2 cases of AOSD resistant to short-acting IL-1 blockade, which were subsequently treated with canakinumab. A retrospective chart review was conducted of patients diagnosed with AOSD in our regional referral center.ResultsResponse to treatment was assessed by its effect on the systemic symptoms (resolution of fever and rash), polyarthritis (using the disease activity score 28--C-reactive protein score), and the levels of serum ferritin. Canakinumab demonstrated sustained efficacy in both patients as evidenced by clinical and laboratory parameters with minimal adverse reactions.ConclusionsThis is the first documented report of successful use of canakinumab, a novel IL-1β inhibitor, in AOSD patients refractory to traditional disease-modifying antirheumatic drugs and short- to moderate-acting IL-1 blockade. Prospective comparative studies are needed to validate canakinumab's efficacy and safety.