Venetoclax+Azacytidine+Modified BUCY Conditioning Regimen for Acute Myeloid Leukemia and Myelodysplastic Syndromes Undergoing Allo-HSCT

Inclusion Criteria:

1. Age 8 to 65 years;
2. Diseases must be MDS and AML; high-risk MDS: int-2 risk, high risk by the IPSS; IPSS-R int-risk (\> 3.5 points), high risk, very high risk; high risk,very high risk by the WPSS; high-risk or relapsed/refractory AML: (1) age≥60 years; (2) High white blood cell count at first diagnosis (WBC≥100\*10\^9/L); (3) secondary AML (previous history of MDS, myeloproliferative disease, or treatment-related AML, etc.); (4) Complicated with extramedullary leukemia, such as central nervous system leukemia, granulocytic sarcoma, hepatosenomegaly; （5）high risk factors and relapsed/refractory AML（reference 2022-AML-ELN guideline）（6）not in remission or ≥CR2 before transplantation;
3. Must need a bone marrow transplant;
4. Must have the ability to observe the efficacy and events;
5. Patient must have ability to understand and willingness to provide written informed consent prior to participation in the study and any related procedures being performed.

Exclusion Criteria:

1. Age \<8 or \>65 years;
2. Uncontrolled bacterial, viral, fungal, or other infection before conditioning regimen;
3. Pregnant or lactating females;
4. Current participation in another clinical trial;
5. Contra-indication to one of the drug of the regimen;
6. Any other severe concurrent disease, or have a history of serious organ dysfunction or disease involving the heart, kidney, liver or other organ system that may place the patient at undue risk to undergo the agents included in the conditioning regimen.