Efficacy of etanercept for the treatment of juvenile idiopathic arthritis according to the onset type

Objective. To assess the efficacy of etanercept in patients with juvenile idiopathic arthritis (JIA), and to assess the tolerance of these patients to etanercept. Methods. All JIA patients with active chronic polyarthritis, who were first treated with etanercept between November 1999 and June 2001 in 18 French centers because of poor response or intolerance to methotrexate, were included in this open-label, prospective, multicenter study. A standardized questionnaire was sent to the treating physicians. We assessed the validated international core-set score for JIA activity every 3 months and performed an intent-to-treat analysis. We also compared the risk of treatment failure in patients defined as having systemic-onset, oligoarticular-onset, or polyarticular-onset JIA. Results. Sixty-one patients were enrolled and were followed up for a median of 13 months. Treatment had to be stopped in 1 patient who became pregnant and in 12 patients due to severe side effects, including neurologic or psychiatric disorders, retrobulbar optic neuropathy, major weight gain, severe infection, cutaneous vasculitis with systemic symptoms, hemorrhagic diarrhea, uveitis flare, and pancytopenia. All of these side effects disappeared after discontinuation of etanercept. Crohn's disease was subsequently diagnosed in 1 child. Scores improved by greater than or equal to30% in 73% of patients after 3 months, but this proportion decreased to 39% after 12 months. The response rate was significantly lower, in patients with systemic-onset JIA than in those with oligoarticular- or polyarticular-onset JIA. Conclusion. Treatment of JIA with etanercept may be associated with a wide spectrum of severe side effects. Although most patients initially respond to etanercept, this initial response is not always followed by sustained improvement over longer periods of time. In addition, the higher rate of treatment failure in the group with systemic-onset JIA indicates that these patients in particular may require alternative treatments.