Canakinumab in Systemic Juvenile Idiopathic Arthritis: Clinical Inactive Disease Rate and Safety in Italian Patients

Abstract

Introduction: Systemic juvenile idiopathic arthritis (sJIA) accounts for 10-20% of all patients with JIA. The demonstration of a key role of IL-1 and IL-6 in the pathogenesis of the disease, led to consider sJIA an autoinflammatory disease: this explain the successfully use of IL-1 and IL-6 inhibitors. While the efficacy and safety of anakinra in sJIA is widely documented, there are no reports on large series of patients treated with canakinumab outside of the setting of clinical trials. Objectives: The aim of this study was to evaluate clinical response rate and disease course of canakinumab in Italian cohort of patients with sJIA. Methods: This is a retrospective multicenter study. Demographic features, previous medical history and therapies was evaluated for each patients. Clinical features, laboratory parameters and adverse events were collected at baseline and after 6 months from starting canakinumab. Clinically inactive disease (CID) was defined according to Wallace criteria. Results: We enrolled 82 (50 F) patients with sJIA treated with canakinumab from 2006 to 2020; 75 of them reached a follow up of 6 months. At baseline 49 patients (59.8%), of which 36 in active disease (AD) and 13 in CID, were previously treated with anakinra, while 33 patients in AD (40.2%) were naïve. At 6 months of follow-up 51/75 patients (68%) met criteria of CID off-glucocorticoids, including all 13 patients in CID at baseline, 19 patients in AD previously treated with anakinra and 19 patients naïve. Twenty-four patients (32%) maintained AD. To evaluated if the response to canakinumab might be related to the baseline features we excluded 13 patients in CID at baseline; we divided the 62 patients in responders (38/62, 61.3%) and non-responders (24/62, 38.7%). There were no significant differences between the two groups regarding demographic, clinical and laboratory parameters, except for a higher number of active joints (p=0.021) and for a greater use of disease-modifying antirheumatic drugs (DMARDs) (p<0.0001) in non-responders patients (Table). No major adverse events nor cases of macrophage activated syndrome were recorded. Conclusion: Canakinumab was able to induce CID in patients in AD at baseline (both in naïve patients and in patients previous treated with anakinra) and to maintain clinical remission achieved with anakinra. The percentage of clinical response is in keeping with what reported in literature, even if we did not found predictive factors of response.