Safety and efficacy of high dose etanercept in treatment of juvenile rheumatoid arthritis.

OBJECTIVE: To evaluate safety and efficacy of high dose etanercept (> 0.8 mg/kg, maximum 25 mg subcutaneously twice weekly) (Enbrel) in children with juvenile rheumatoid arthritis (JRA) and inadequate prior response to standard dose etanercept. METHODS: Retrospective chart review of 8 children (6 girls, 2 boys, mean age 8.4 yrs, range 5-16 yrs). Five children had systemic onset, polyarticular course JRA; 2 had polyarticular onset; and one had pauciarticular onset, polyarticular course JRA. All children had failed at least 3 mo (mean 9 mo) treatment with standard dose etanercept (0.4 mg/kg SC twice a week). All 8 children had increase in the etanercept dose to at least 0.8 mg/kg (mean 1.1 mg/kg, maximum 25 mg SC twice weekly) for a mean of 7 mo (range 3-10 mo). Efficacy of high dose etanercept was evaluated by changes in joint count, laboratory data, and ability to decrease concomitant medication. RESULTS: Improvements in the joint count and laboratory findings (erythrocyte sedimentation rate, hemoglobin and platelet count) were observed in 2 of 8 (25%) children. In these 2, concomitant prednisone was reduced or discontinued. In contrast, no changes in disease activity or laboratory findings were observed in the other 6 children. Overall, high dose etanercept was well tolerated. No laboratory abnormalities were detected and no child withdrew because of adverse events. CONCLUSION: High dose etanercept is safe and well tolerated in children, but efficacy seems limited. In children with unsatisfactory response to standard dose etanercept, an increased dose or treatment prolongation may not offer any additional benefit.