Study of Blinatumomab Administration in Chinese Pediatric Participants With Relapsed/Refractory B Precursor Acute Lymphoblastic Leukemia (R/R B-ALL)

Inclusion Criteria: * Participant's parent or legally authorized representative has provided informed consent when the participant is legally too young to provide informed consent and the participant has provided written assent based on local regulations and/or guidelines prior to any study-specific activities/procedures being initiated * Pediatric participants aged \> 1 month and \< 18 years at the time of informed consent * Relapsed or/refractory precursor B-cell acute lymphoblastic leukemia (ALL) disease, defined as ≥5% bone marrow blasts with at least one of the following: * Second or later bone marrow relapse; * Any marrow relapse after allogeneic hematopoietic stem cell transplant (alloHSCT); * Refractory to other treatments: * For participants in first relapse: failure to achieve a complete remission (CR) following a full standard reinduction chemotherapy regimen * For participants who have not achieved a first remission, failure to achieve remission following a full standard induction regimen * Karnofsky performance status ≥ 50% for participants ≥ 16 years * Lansky performance status ≥ 50% for participants \< 16 years Exclusion Criteria: \- Evidence of current central nervous system (CNS) involvement by ALL. Participants with CNS disease at the time of relapse are eligible if CNS is successfully treated prior to enrollment. Other Medical Conditions * Clinically relevant CNS pathology requiring treatment (eg, unstable epilepsy). * Isolated extramedullary (EM) dise…