Etanercept is effective in juvenile idiopathic arthritis (JIA).^1–,³ Currently it is administered subcutaneously at a dose of 0.4 mg/kg (maximum of 25 mg) twice a week. Clinical trials in adults show that administration of a double dose once a week is effective enough to induce and retain remission.^4,5 A pharmacokinetic model developed by Yim et al⁶ indicates that the same dosing regimen could be used in children. Wallace⁷ mentions the once weekly double dose in patients with JIA, but this is not supported by clinical trials. Therefore we evaluated the efficacy of etanercept administered subcutaneously once a week at a dose of 0.8 mg/kg (maximum of 50 mg) to retain and induce remission in patients with JIA.

Eleven patients with JIA, in remission, who had already been treated with etanercept twice a week at the usual dose were switched to the double dose of 0.8 mg/kg subcutaneously once a week. Two patients with JIA in whom etanercept at a dose of 0.8 mg/kg subcutaneously once a week was initiated were observed from the start of the treatment, to see if remission could be induced.

Table 1⇓ shows the patient and disease characteristics. The outcome measures used to assess disease activity consisted of the following set of seven response variables: global assessment of disease activity by the physician and of pain and well-being by the patient all by visual analogue scale, Children Health Assessment Questionnaire, number of active joints, number of limited joints, and erythrocyte sedimentation rate. Patients were evaluated at the start of the study and after three months.

Table 1A⇑ summarises the data for patients for whom the administration of etanercept was switched to a double dose once a week. The equality between the response variables at the start of the study and after 3 months indicates remission according to the criteria of Wallace et al.⁸ None of the patients had a flare during the 3-month course of the study according to the definition of Brunner et al.⁹

Table 1B⇑ summarises the data for patients for whom etanercept was initiated at a double dose once a week. It is notable that there was a major improvement in all the response variables, except for the number of limited joints, which stayed the same. Lovell et al¹ modified this variable in their study because it is not a quick response variable and therefore not a good marker for short-term studies. The improvement in both patients met the definition of Giannini et al.¹⁰

There were no serious adverse events.

A limitation of this study is the open-label design, but a double-blind comparison of the two regimens would require a number of patients with JIA that is almost impossible to recruit.

In conclusion, our clinical study supports what has been reported in theory in the literature, namely that the once weekly double dose of etanercept is just as effective at retaining remission in patients with JIA. Considering the good outcome in the two patients in whom etanercept was initiated at the once weekly double dose, it can also induce remission of JIA.