Open-Label Extension of the Dose Finding Study (DSC/08/2357/36) in Patients With Poly Juvenile Idiopathic Arthritis

Inclusion Criteria: * subjects who had successfully completed the previous Dose Finding Study and were fully compliant to the inclusion/exclusion criteria described in the previous DSC/08/2357/36 Exclusion Criteria: * patients with fever related to JIA or other systemic features of JIA during 12 months before entering the study * active bacterial or mycotic infection requiring antimicrobial treatment * episode of macrophage activation syndrome over the last 6 months * baseline prolongation of QT/QTc interval, use of concomitant medications that prolong the QT/QTc interval or history of additional risk factors for TdP. * clinically significant cardiovascular disease * clinically significant illness i.e. any condition that in the opinion of the Investigator places the patient to unacceptable risk for adverse outcome if he/she were to participate in the study * psychiatric illness/social situation that would limit compliance with study medication and protocol requirements * inherited metabolic diseases * presence of malignancy * pregnancy or lactation * positive blood test for HIV * active EBV infection, active B and/or C hepatitis * platelet count \<100x10(9)/L