Expanded Access Protocol - Blinatumomab in Pediatric & Adolescent Subjects With Relapsed/Refractory B-precursor ALL

Primary Objective: To estimate the incidence of treatment-emergent and treatment-related adverse events during treatment with blinatumomab in pediatric and adolescent subjects with B-precursor ALL in second or later bone marrow relapse, in any marrow relapse after alloHSCT, or refractory to other treatments Secondary Objective(s): To describe key efficacy outcomes, including incidence of complete response (CR) within 2 cycles of blinatumomab, minimal residual disease (MRD) remission within 2 cycles of blinatumomab, relapse free survival (RFS), overall survival (OS), incidence of alloHSCT, and 100-day mortality after alloHSCT. Hypotheses: A formal statistical hypothesis will not be tested. The incidence of treatment-emergent and treatment-related adverse events will be estimated. Study Endpoints: * Incidence of treatment-emergent and treatment-related adverse events * Incidence of CR within 2 cycles of blinatumomab * MRD remission within 2 cycles of blinatumomab * RFS * OS * Incidence of alloHSCT * 100-day mortality after alloHSCT Study Design: Multi-center, open-label, single-arm expanded access protocol