A range of factors associated with response to etanercept therapy have been examined in 262 patients with JIA on the Dutch arthritis and biologicals in children register. 15 months after therapy commenced, 32% of patients were determined to have excellent response and 32% poor response. An excellent response (characterized as inactive disease or early etanercept discontinuation) was associated with a lower disability score and prior DMARD therapy, whereas a poor response (characterized as <50% improvement or therapy discontinuation owing to ineffectiveness or intolerance) was more likely if the patient was female or had systemic JIA.