The cryopyrin-associated periodic syndrome (CAPS) is a rare inherited inflammatory disease associated with overproduction of interleukin-1. Canakinumab is a human anti–interleukin-1β monoclonal antibody.

Interleukin-1 is pivotal in the pathogenesis of systemic juvenile idiopathic arthritis (JIA). We assessed the efficacy and safety of canakinumab, a selective, fully human, anti–interleukin-1β monoclonal antibody, in two trials. In trial 1, we randomly assigned patients, 2 to 19 years of age, with systemic JIA and active systemic features (fever; ≥2 active joints; C-reactive protein, >30 mg per liter; and glucocorticoid dose, ≤1.0 mg per kilogram of body weight per day), in a double-blind fashion, to a single subcutaneous dose of canakinumab (4 mg per kilogram) or placebo. The primary outcome, termed adapted JIA ACR 30 response, was defined as improvement of 30% or more in at least three of the six core criteria for JIA, worsening of more than 30% in no more than one of the criteria, and resolution of fever. In trial 2, after 32 weeks of open-label treatment with canakinumab, patients who had a response and underwent glucocorticoid tapering were randomly assigned to continued treatment with canakinumab or to placebo. The primary outcome was time to flare of systemic JIA. At day 15 in trial 1, more patients in the canakinumab group had an adapted JIA ACR 30 response (36 of 43 [84%], vs. 4 of 41 [10%] in the placebo group; P<0.001). In trial 2, among the 100 patients (of 177 in the open-label phase) who underwent randomization in the withdrawal phase, the risk of flare was lower among patients who continued to receive canakinumab than among those who were switched to placebo (74% of patients in the canakinumab group had no flare, vs. 25% in the placebo group, according to Kaplan–Meier estimates; hazard ratio, 0.36; P=0.003). The average glucocorticoid dose was reduced from 0.34 to 0.05 mg per kilogram per day, and glucocorticoids were discontinued in 42 of 128 patients (33%). The macrophage activation syndrome occurred in 7 patients; infections were more frequent with canakinumab than with placebo. These two phase 3 studies show the efficacy of canakinumab in systemic JIA with active systemic features. (Funded by Novartis Pharma; ClinicalTrials.gov numbers, NCT00889863 and NCT00886769.)

The linear ubiquitination complex (LUBAC) is poorly understood in humans. Casanova and colleagues identify natural mutations in a component of human LUBAC and use this to dissect its function in vivo and in vitro. We report the clinical description and molecular dissection of a new fatal human inherited disorder characterized by chronic autoinflammation, invasive bacterial infections and muscular amylopectinosis. Patients from two kindreds carried biallelic loss-of-expression and loss-of-function mutations in HOIL1 (RBCK1), a component of the linear ubiquitination chain assembly complex (LUBAC). These mutations resulted in impairment of LUBAC stability. NF-κB activation in response to interleukin 1β (IL-1β) was compromised in the patients' fibroblasts. By contrast, the patients' mononuclear leukocytes, particularly monocytes, were hyper-responsive to IL-1β. The consequences of human HOIL-1 and LUBAC deficiencies for IL-1β responses thus differed between cell types, consistent with the unique association of autoinflammation and immunodeficiency in these patients. These data suggest that LUBAC regulates NF-κB–dependent IL-1β responses differently in different cell types.

To assess the efficacy of the interleukin 1 receptor antagonist anakinra in systemic-onset juvenile idiopathic arthritis (SJIA). A multicentre, randomised, double-blind, placebo-controlled trial was conducted. The primary objective was to compare the efficacy of a 1-month treatment with anakinra (2 mg/kg subcutaneous daily, maximum 100 mg) with a placebo between two groups each with 12 patients with SJIA. Response was defined by a 30% improvement of the paediatric American College of Rheumatology criteria for JIA, resolution of systemic symptoms and a decrease of at least 50% of both C-reactive protein and erythrocyte sedimentation rate compared with baseline. After month 1 (M1), patients taking placebo were switched to anakinra. Secondary objectives included tolerance and efficacy assessment for 12 months, and analyses of treatment effect on blood gene expression profiling. At M1, 8/12 responders were receiving anakinra and 1 responder receiving placebo (p=0.003). Ten patients from the placebo group switched to anakinra; nine were responders at M2. Between M1 and M12, six patients stopped treatment owing to an adverse event (n=2), lack of efficacy (n=2) or a disease flare (n=2). Blood gene expression profiling at enrollment and at 6 months' follow-up showed one set of dysregulated genes that reverted to normal values in the clinical responders and a different set, including interferon (IFN)-inducible genes, that was induced by anakinra. Anakinra treatment is effective in SJIA, at least in the short term. It is associated with normalisation of blood gene expression profiles in clinical responders and induces a de novo IFN signature. NCT00339157.