∙ Subjects must meet all of the following criteria to be enrolled:

• Subjects volunteer to participate in clinical trails, understand and inform the trials and sign informed consent form, be willing to complete all the trial procedures;

• Aged from 18 to 70 years (including cut-off value), Male and female;

• Expected survival \> 12 weeks;

• Previously diagnosed as Acute Myeloid Leukemia by ELN updated criteria (2017) and one of the following indicators that is satisfied:

‣ AML patients who have not achieved complete remission (CR) after at least three cycles of standard induction therapy, or

⁃ AML patients who achieved complete remission after induction therapy but relapsed within one year, or

⁃ AML patients who achieved complete remission after induction therapy for more than one year but did not achieve remission after one cycle of chemotherapy with the original regimen following relapse, or

⁃ AML patients who relapsed after transplantation, or

⁃ AML patients who experienced two or more relapses. Note: For patients meeting conditions a), b), or c) with FLT3 mutations, they must have undergone at least one treatment with a tyrosine kinase inhibitor (TKI) without achieving complete remission or have relapsed after achieving complete remission, except for those who cannot tolerate TKI therapy or have contraindications to TKI treatment.

• Positive for FLT3 mutation confirmed by leukemia cell genetic testing, or FLT3 expression ≥35%;

• ECOG performance status score of 1-2;

• Liver, kidney, heart, and lung functions meeting the following criteria:

‣ Glomerular filtration rate (GFR) ≥60 ml/min/1.73 m² or serum creatinine ≤2 times the upper limit of normal (ULN);

⁃ Serum AST and ALT ≤3 times of ULN, and total bilirubin ≤1.5 times the ULN;

⁃ Oxygen saturation \> 92%;

⁃ Left ventricular ejection fraction (LVEF) ≥50%, with no pericardial effusion observed on ultrasound, and no clinically significant electrocardiographic abnormalities.

• Able to understand the study and sign the informed consent form.