Study is completed (was active and ongoing but no longer recruiting since December 2014). The study Data Monitoring Committee meeting communicated to Novartis the following safety findings in the study population: high rate of premature discontinuation of study medication, high rate of post-transplant lymphoproliferative disease and high rate of related serious infections leading to hospitalization. In light of the safety findings, Novartis followed the DMC recommendation to discontinue the study medication in this age group and to stop enrolling new patients in this study (regardless of age).