TNF inhibitors in pediatric rheumatic diseases

Abstract

In juvenile idiopathic arthritis (JIA) and Kawasaki disease (KD), the most common pediatric rheumatic diseases, there is a certain number of patients who are refractory to anchor drugs such as methotrexate and immunoglobulin. With the advent of tumor necrosis factor (TNF) inhibitors, these refractory cases can now be treated. In Japan, TNF inhibitors first became available for use in pediatric patients in 2009 and currently include etanercept (ETN), a soluble receptor construct, adalimumab (ADA), a fully human monoclonal antibody, and infliximab, a chimeric monoclonal antibody. For JIA with active polyarticular joints refractory to methotrexate, ETN is injected subcutaneously at 0.2 to 0.4 mg/kg twice weekly, and ADA is injected subcutaneously at 20 or 40 mg every two weeks. The efficacy of ETN and ADA in arthritis is comparable, but it is hoped that further clinical trials will allow stratified treatment. ADA is more effective in uveitis. For Kawasaki disease refractory to intravenous immunoglobulin (1st line), infliximab is given as a single 5 mg/kg intravenous infusion. It can be administered from the 2nd line, but should be administered in specialized centers experienced in the use of the 3rd line.