Detectable measurable residual disease (MRD) is the most important prognostic factor for B-cell acute lymphoblastic leukemia (B-ALL) for overall survival (OS) and disease-free survival (DFS). Patients who are MRD positive and have no access to novel immunotherapies should receive an allogeneic hematopoietic stem cell transplantation (HSCT). Blinatumomab is considered a standard of care (SOC) for this group of patients, however, the ideal treatment dose for MRD is unknown as doses were adjusted from the relapsed/refractory setting. Preliminary data suggest short cycles of blinatumomab can also be effective in states of lower disease burden prior to transplant. Thus, the investigators are performing a phase 2 trial assessing 7 days of blinatumomab as a bridge to HSCT

Primary endpoint is assessing the MRD response following a short-course blinatumomab infusion in patients with B-ALL with complete response (CR) and have detectable MRD disease who are candidates for HSCT. Secondary endpoints include incidence of adverse events, OS, DFS, percentage of patients who receive HSCT, incidence of cytokine release syndrome (CRS) and immune effector cell associated neurotoxicity syndrome (ICANS)

During the proposed treatment, blinatumomab therapy will be assigned as follows:

Blinatumomab 17.5 mcg per day for 2 days, followed by blinatumomab 28 mcg per day for 5 days. Dexamethasone 20 mg will be applied one hour before starting dose.

The immunotherapy will be applied as a 24-hour continuous infusion. The scheduled appointments will be on the initial day of blinatumomab, when the patient will be discharged from hospital and evaluation will be performed on day 10 with bone marrow aspiration and MRD assessment trough next generation flow cytometry. The results will be given at the appointment on day 14, along with an assessment profile for HSCT.

Inclusion Criteria:

• Philadelphia chromosome-negative B-cell acute lymphoblastic leukemia
• MRD detectable in complete response (above the limit of quantification according to FCM)
• Performance status 0-2 on the ECOG scale
• No prior organ damage
• Having a potential related or unrelated donor

Exclusion Criteria:

• Performance status on the ECOG scale >2
• HCT-CI >3 points
• Patients who do not wish to participate in clinical study.
• Active central nervous system infiltration (CNS3)
• Active extramedullary disease
• Having previously received blinatumomab
• Absence of related or unrelated donors