To explore the efficacy and safty of Blinatumomab as a bridge to Allogeneic Hematopoietic Stem Cell Transplantation in High Risk Precursor B-cell Acute Lymphoblastic Leukemia

High Risk Precursor B-cell Acute Lymphoblastic Leukemia is a kind of leukemia with poor prognosis. Here, we want to explore the efficacy and safty of Blinatumomab as a bridge to Allogeneic Hematopoietic Stem Cell Transplantation in High Risk Precursor B-cell Acute Lymphoblastic Leukemia.

Inclusion Criteria:

1. The patients meet the diagnostic criteria for high risk precursor B-ALL (according to the 2016 WHO classification) and are under hematologic remission.
2. ECOG score is 0-2.
3. Expecting life span is more than 6 months.
4. Patients are free from severe organ dysfunction.

Exclusion Criteria:

1. Patients are combined with severe organ dysfunction: Organ failure: Cardiac failure: ejection fraction(EF) <30%, NYHA standard, cardiac function not Full Grade II or above; Liver and kidney insufficiency: serum total bile Erythroid ≥2mg/dl, AST or ALT≥ upper limit of normal 2.5-fold, serum creatinine (SCr) >2.5mg/ dL or blood Creatinine clearance rate < 30ml/min.
2. Patients are combined with infection or other complications that can not tolerate chemotherapy.
3. Patients are suffering from central nervous system/solitary extramedullary leukemia.
4. Patients are considered as tumer progression.
5. Patients has undergone allogeneic hematopoietic stem cell transplantation or underwent autologous stem cell transplantation within 6 weeks or other immunotherapy within 4 weeks.
6. Pregnant and lactating women will not be included.