Study of Tisagenlecleucel in Chinese Pediatric and Young Adult Subjects With Relapsed or Refractory B-cell ALL

The study will have the following sequential phases for all subjects: * Screening * Pre-Treatment (Cell Product Preparation and Lymphodepleting Chemotherapy) * Treatment and Follow-up Tisagenlecleucel infusion should occur within 16 weeks of informed consent. The total duration of the study is 5 years. After tisagenlecluecel infusion, efficacy will be assessed monthly for the first 6 months, then quarterly up to 2 years and semi-annually afterwards up to 5 years, or until the subject relapses.