A Study of Subcutaneous Blinatumomab Administration in Participants With R/R and MRD+ B-ALL

Inclusion Criteria: * Ph-IIC, Dose Escalation and Dose Expansion: Aged 18 years or older (or same or greater than legal age within the country if it is older than 18 years). * Ph-IIRa and Ph-IIMa: Aged ≥ 17 years at time of informed consent. * Ph-IIRb and Ph-IIMb: Age ≥ 12 years and \< 17 years at time of informed consent. * Ph-IIR, Ph-IIC, Dose escalation, Dose Expansion: Participants with R/R B-precursor ALL. * Relapsed or Refractory B-precursor ALL at any time after first salvage therapy. * Relapsed B-precursor ALL at any time after allogenic hematopoietic stem cell transplant (HSCT). * Ph-IIR, Ph-IIC, Dose escalation, Dose expansion: Greater than or equal to 5% blasts in the Bone Marrow per local assessment. * Ph-IIM: B-precursor ALL and bone marrow blasts (BMB) ≥ 0.01% and \< 5% per local assessment. * Ph-IIM: Availability of an appropriate archival BM specimen from initial or relapse diagnosis and the screening BM sample. * Participants aged ≥ 18 years: Eastern Cooperative Oncology Group (ECOG) Performance Status less than or equal to 2. * Participants aged 16 to \< 18 years old: Karnofsky Performance Score ≥ 50%. * Participants aged \< 16 years old: Lansky Performance Score ≥ 50%. * Any Ph+ participant intolerant or refractory to prior tyrosine kinase inhibitors (TKIs) are eligible. * Ph-IIM: BM function as follows: * Absolute Neutrophil Count (ANC) ≥ 500/μL * Platelet count ≥ 50 000/μL (transfusion permitted) * Hemoglobin level ≥ 9 g/dL (transfusion permitted)…