Background Juvenile idiopathic arthritis (JIA) is a chronic rheumatic disease with onset before 16 years. According ILAR classification there are several subtypes were defined based on number of joints and clinical and laboratorial features. Polyarticular course includes patients with more than 4 affected active joints and consists of RF-positive and RF-negative polyarticular JIA (pJIA) and extended oligoarticular JIA. Methotrexate (MTX) is standard therapy for patients with pJIA. Patients who fall or not tolerated to MTX usually treated by biologics, block the main pro-inflammatory cytokines such as TNFα, Il-1 and IL-6. Recently, toclizumab, an anti-Il-6-receptor antibody has been approved for pJIA in children after 2 years.
Objectives The aim of our study to evaluate the efficacy and safety of tocilizumab in children with pJIA.
Methods In the retrospective observation study were included 20 children (85% girls) with active pJIA, who were resistant to previous therapy with MTX alone or with combination with other non-biologic DMARDs and were treated with IV infusion of tocilizumab in the dosage 8 mg/kg every 4 weeks. The onset age was 2.85 (1.4; 6.4) years, the interval between onset of JIA and start of TCZ was 6.0 (1.6; 9.8). The duration of TCZ ranged 6 to 42 months (since 2010). 25% of patients were received tocilizumab monotherapy.
Results NSAIDS were successfully discontinued in all patients during the trial, in 4 patients second non-biologic DMARD was successfully discontinued and methotrexate was discontinued in 3 patients. Erythrocyte sedimentation rates (p=0.001), C-reactive protein (p=0.005), WBC (p=0.001) and platelets (p=0.002) count were significant decreased to normal range during the first 6 months, then number of active joints decreased slower (p=0.01) (Fig.1). During the trial 8 (44.4%) patients in different time reached the status of inactive disease (ID) according the C. Wallace criteria. There were no significant differences in achievement of ID between biologic-naive patients (n=12) and patients who were treated with biologics before (n=8, p=0.18). The main predictors of achievement of ID were CRP ≤7.5 mg/l (HR=5.3, p=0.035), ESR ≤19 mm/h (HR=8.9; p=0.01) and tocilizumab monotherapy (HR=9.1; p=0.01). The more frequent adverse events (AE) were transient hypercholesterolemia, and single episodes of low-grade neutropenia which did not lead to tocilizumab discontinuation or using any other medications.
Conclusions In our study the long-term efficacy and safety of tocilizumab in children with pJIA was shown. During the trial the high proportion of children reached the ID. The tocilizumab monotherapy was as effective as combination with methotrexate. No significant differences were observed in achievement of ID between biologic-naive patients and children, who fall previous biologic treatment. No serious AE leading to tocilizumab discontinuation were detected during the trial.
Disclosure of Interest None declared