Biologics with or without methotrexate in treatment of polyarticular juvenile idiopathic arthritis: effectiveness, safety and drug survival

To investigate the impact of additionally given MTX on biologic treatment of polyarticular JIA in terms of effectiveness, safety and drug survival.Patients suffering from polyarticular JIA and treated with either monotherapy with a first biologic or a combination of a biologic and MTX were selected from the BIKER registry. The TNF-α inhibitors (TNFi) adalimumab, etanercept and golimumab and the IL-6 inhibitor tocilizumab were considered. Upon a non-randomized study design, we adjusted the different cohorts using propensity score matching to improve comparability.A total of 2148 patients entered the analysis, who were treated by either combination therapy (n = 1464) or monotherapy (n = 684). Disease activity declined significantly more in patients upon combination therapy than upon biologic monotherapy. Comparison of adjusted cohorts revealed that patients who received TNFi gained more benefit from additionally given MTX than patients treated with tocilizumab. Median survival time of therapy with biologics was significantly longer upon combination therapy (3.1 years) than with monotherapy (2.7 years), as demonstrated by a Kaplan-Meier analysis (log rank test: P = 0.002). The safety profile was moderately affected by additional MTX due to increased incidence of gastrointestinal and hepatic adverse events. Serious adverse events occurred at an equal rate of 3.6 events per 100 patient-years in both cohorts.Additionally given MTX improves the effectiveness of biologic treatment in polyarticular JIA without seriously compromising treatment safety. Especially TNFi benefit from combination, while no improvement in outcome has been observed by combining tocilizumab with MTX.