Pediatric-type Therapy With Pre-transplant Blinatumomab for HR Patients - Phase II Study

Inclusion Criteria: 1. Age ≥ 18 years and \<30 years of age at the time of signing the informed consent document. 2. Have a documented diagnosis of Ph-neg ALL, LBL or MPAL according to the WHO 2016 classification (appendix I). 3. Females of childbearing potential (FCBP) may participate, providing they meet the following conditions: Agree to use at least two effective contraceptive methods (oral, injectable, or implantable hormonal contraceptive; tubal ligation; intra-uterine device; barrier contraceptive with spermicide; or vasectomized partner) throughout the study, and for 3 months following EOT; and have a negative serum or urine pregnancy test (investigator's discretion; sensitivity at least 25 mIU/mL) at screening; and have a negative serum or urine pregnancy test (investigator's discretion) within 72 hours prior to starting study therapy in the treatment phase (note that the screening serum pregnancy test can be used as the test prior to starting study therapy in treatment phase if it is performed within the 72-hour timeframe). 4. Male subjects with a female partner of childbearing potential must agree to the use of at least two physician-approved contraceptive methods throughout the course of the study and should avoid fathering a child during the course of the study and for 3 months following the last dose of study drug. 5. Understand and voluntarily sign an informed consent document prior to any study related assessments/procedures being conducted. 6. Able to adhere to the study visit schedule and other protocol requirements. Exclusion Criteria: 1. Age \<18 or over 30 years at the time of signing the informed consent document. 2. Ph-positive disease. 3. Known Human Immunodeficiency Virus (HIV). 4. Known or suspected hypersensitivity to any of the study drugs. 5. Pregnant or lactating females. 6. Any significant medical condition, laboratory abnormality, or psychiatric illness that would prevent the subject from participating in the study. 7. Any condition including the presence of laboratory abnormalities, which places the subject at unacceptable risk if he/she were to participate in the study. 8. Participation to an investigational drug trial in the last month before randomization.