Etanercept treatment results in children with non-systemic juvenile idiopathic arthritis: remission, recrudescence, and adverse events. retrospective cohort study

Background.Etanercept is a biological drug most commonly used in patients with juvenile idiopathic arthritis (JIA). The results of its use are showed in local studies.Objective.Our aim was to evaluate the efficacy and safety of the use of etanercept in children with non-systemic JIA, to determine the predictors of remission and the risk factors for the development of exacerbations.Methods.In a retrospective cohort study, the results of etanercept treatment (remission, exacerbations, adverse events) in children with non-systemic JIA were analyzed. The minimum follow-up period was 6 months.Results.The period of remission within 6–36 months occurred in 77/131 (58.8%), exacerbations developed in 18/129 (14.0%) patients. Predictors of achieving remission were the age of JIA onset < 8 years [relative risk (RR) 2.05; 95% confidence interval (CI) 1.27–3.23], the age of prescribing etanercept ≤ 10 years (RR 1.7, 95% CI 1.22–2.38), the time of the disease prior to etanercept prescription < 2.5 years (RR 2.4, 95% CI 1.4–4.4), the presence of HLA-B27 antigen (RR 2.15, 95% CI 0.98–4.75; p = 0.06). The risk of exacerbations was higher in children with polyarticular JIA (RR 2.7, 95% CI 0.9–8.2; p = 0.08), whereas methotrexate therapy reduced the risk of exacerbations (RR 0.32, 95% CI 0.1–1.15; p = 0.05). Etanercept was discontinued due to primary (improvement by the ACRpedi criteria after 3 months of therapy <30%) or secondary (loss of previously achieved ≥ 30% improvement) failure in 14/152 (9.2%) patients; de novo uveitis developed in 8/152 (5.3%) patients; reactions at the injection site — in 6/152 (4.0%) patients.Conclusion.Therapy involving etanercept is more likely to induce remission in younger patients with JIA onset at the age of 8 years and a history of less than 2.5 years. A high risk of exacerbations was noted in patients with polyarticular JIA, and low one — in those receiving methotrexate as a part of combined therapy.