Study to Investigate Intravenous Blinatumomab in Japanese Adult Participants with Newly Diagnosed Philadelphia-negative B-precursor Acute Lymphoblastic Leukemia (B-ALL)

• Japanese adult participants ≥ 18 years and ≤ 70 years at enrollment. • Participant should have newly diagnosed B-cell precursor (BCP) • Philadelphia-negative ALL in CR/CRh after induction/consolidation therapy with any MRD (+ or -). • CR/CRh as defined in Section 11.10, Appendix 10 after induction and at any time during consolidation chemotherapy with ALL MRD2008/2019/2023 protocol regimen or 3 blocks of Hyper-CVAD. • Bone marrow function as defined below: - Absolute neutrophil count (ANC) (Neutrophils) ≥500/μL - Platelets ≥50.000/μL (transfusion permitted) • Adequate renal and hepatic function: - Total bilirubin (TBL) ≤ 2.0 x upper limit of normal (ULN) (ULN; unless Gilbert’s Disease or if liver involvement with leukemia) - Creatinine clearance ≥50 mL/min/1.73 m^2 • Eastern Cooperative Oncology Group performance status (ECOG PS) ≤ 2.

Disease Related • Current infiltration of cerebrospinal fluid (CSF) by ALL. If screening CSF demonstrates leukemic blasts, participants must receive intrathecal treatment and demonstrate negative CSF before enrollment and starting blinatumomab infusion. • Immunotherapy (eg, rituximab, alemtuzumab) within 4 weeks before start of protocol-specified therapy. Other Medical Conditions • History of relevant central nervous system (CNS) pathology or current relevant CNS pathology (e.g., seizure, paresis, aphasia, cerebrovascular ischemia/hemorrhage, severe brain injuries, dementia, Parkinson’s disease, cerebellar disease, organic brain syndrome, psychosis, or coordination or movement disorders). • Current autoimmune disease or history of autoimmune disease with potential CNS involvement. • Active uncontrolled infection requiring therapy. • History of other malignancy within the past 3 years, with the following exceptions: -Malignancy treated with curative intent and with no known active disease present for ≥ 3 years before enrollment and felt to be at low risk for recurrence by the treating physician. - Adequately treated nonmelanoma skin cancer or lentigo maligna without evidence of disease. - Adequately treated cervical carcinoma in situ without evidence of disease. - Adequately treated breast ductal carcinoma in situ without evidence of disease. - Prostatic intraepithelial neoplasia without evidence of prostate cancer. - Adequately treated urothelial papillary noninvasive carcinoma or carcinoma in situ. Prior/Concomitant Therapy • Systemic cancer chemotherapy within 2 weeks prior to study treatment (except for intrathecal prophylaxis) • Known infection with human immunodeficiency virus (HIV) or chronic infection with hepatitis B virus or hepatitis C virus. In Japan, follow the JSH Guidelines for the Management of Hepatitis B Virus Infection version 4 (The Japan Society of Hepatology, 2022) for the screening of Hepatis B virus infection. • Radiotherapy within 4 weeks prior to study treatment. Prior/Concurrent Clinical Study Experience • Currently receiving treatment in another investigational device or drug study, or less than 30 days since ending treatment on another investigational device or drug study(ies). This does not apply to other investigational procedures or participation in observational research studies while participating in this study are excluded. Other Exclusions • Participants of childbearing potential unwilling to use protocol-specified method of contraception during treatment and for an additional 48 hours after the last dose of blinatumomab. • Participants who are breastfeeding or who plan to breastfeed while on study through 48 hours after the last dose of blinatumomab. • Participants planning to become pregnant or donate eggs while on study through 48 hours after the last dose of blinatumomab. • Participants of childbearing potential with a positive pregnancy test assessed at screening by a highly sensitive urine or serum pregnancy test. • Participant has known hypersensitivity to blinatumomab or to any component of the product formulation. • Participant likely to not be available to complete all protocol-required study visits or procedures, and/or to comply with all required study procedures (e.g., Clinical Outcome Assessments) to the best of the participant and investigator’s knowledge. • History or evidence of any other clinically significant disorder, condition, or disease (except for those outlined above) that, in the opinion of the investigator or Amgen physician, if consulted, would pose a risk to participant safety, or interfere with the study evaluation, procedures, or completion.