The study “A randomized, two armed, single blind, parallel, active controlled, and non inferiority clinical trial to Compare Efficacy and Safety of anti TNF alfa biosimilar molecules to the originators in children with active Juvenile Idiopathic Arthritis” (CEST-JIA) is aimed to evaluate, through a pragmatic trial, safety and efficacy of switching from the adalimumab and etanercept originator molecules versus their biosimilar competitors and vice-versa in children with JIA in clinical remission on anti-TNF medication.