Safety and efficacy of long-term etanercept in the treatment of methotrexate-refractory polyarticular-course juvenile idiopathic arthritis in Japan

Previous short-term trials found etanercept (0.2 or 0.4 mg/kg) to be effective and well tolerated in Japanese children with juvenile idiopathic arthritis (JIA) who were intolerant/resistant to methotrexate. The aim of this study was to evaluate the long-term safety and efficacy of etanercept in Japanese children with JIA. Patients (4-19 years) who received etanercept in one of three short-term studies continued onto this long-term open-label study. Of the 32 patients enrolled, 18 (56.3%) completed 192 weeks of the study and 14 (43.8%) were discontinued; 7 (21.9%) for patient refusal, 2 (6.3%) for adverse events (AEs), and 5 (15.6%) for lack of efficacy. All patients reported AEs; 31 (96.9%) reported infections and 6 (18.8%) reported serious AEs. Main efficacy assessments included change from baseline in the American College of Rheumatology Pediatric core components, including mean improvements from baseline in the physician global assessment (90.7%), patient/guardian global assessments (54.1%), Childhood Health Assessment Questionnaire (84.6%), and median improvements in C-reactive protein levels (92.7%). No unexpected safety results were reported, and early efficacy responses were sustained in the long term. This study provides further evidence that etanercept is an effective therapeutic option for Japanese children with polyarticular-course JIA.