This project is a prospective, single-center study to evaluate the efficacy, safety and related mechanisms of azacitidine combined with low-dose dasatinib in maintenance therapy in patients with intermediate and high-risk acute myeloid leukemia(AML). The patients were randomly divided into azacitidine group and azacitidine combined with low-dose dasatinib group. The overall survival and disease-free survival were taken as the main end points, and the mortality and recurrence rate were taken as the secondary end points, meanwhile, the incidence of adverse events were evaluated. At the same time, the mRNA expressions of DNA methyltransferase (DNMT1, DNMT3a, DNMT3b), tumor suppressor genes (TP53, P15, P16, P21, CDH1, DOK6, SHP1, PTPN11) and differentiation genes (pu.1, C/EBP α, C/EBP β) were detected. Pyrophosphate sequencing was used to detect the methylation level of the promoter region of these tumor suppressor genes. Western Blot was used to detect apoptosis proteins (caspase3, caspase8) and phosphorylated proteins (pSTAT3, pSTAT5, pAKT). The proportion of apoptotic population of bone marrow cells was determined by flow cytometry. Therefore, the data in this study will reflect the efficacy and safety of azacitidine or azacitidine combined with low-dose dasatinib in real-world maintenance therapy in patients with medium and high-risk AML.

In addition to studying the overall survival, disease-free survival and recurrence rates, mortality and incidence of adverse events of patients treated with azacitidine or azacitidine combined with low-dose dasatinib, we will also study its related mechanisms. One of the pathogenesis of AML is that abnormal DNA methylation makes the cell cycle out of control and carcinogenesis by inhibiting the expression of tumor suppressor genes. In addition, the abnormal activation of tyrosine kinase signal pathway also promotes the development of leukemia. Azacitidine, the hypomethylating agents, can not only inhibit the DNA methyltransferase family, but also activate tumor suppressor genes to inhibit a variety of tyrosine kinase signaling pathways, including JAK-STAT. NaShen et al have directly demonstrated that tyrosine kinase inhibitors (TKIs) can not only inhibit the abnormal activation of tyrosine kinase pathway, but also reduce DNA methylation. This study found that the combination of the second generation TKIs and hypomethylating agents can reduce has a synergistic effect on promoting apoptosis and reducing DNA methylation. In addition, TKIs often produces drug resistance due to long exposure time, and the main mechanisms of drug resistance is due to DNA methylation and abnormal reactivation of tyrosine kinase signal pathway. The combination of TKI and azacitidine reduces DNA methylation and inhibits the reactivation of abnormal tyrosine kinase signal pathway, which is helpful to improve TKI drug resistance. Based on the above theory, we assume that patients treated with azacitidine and dasatinib may have more obvious demethylation effect, increased expression of tumor suppressive genes, more obvious apoptosis, and inhibition of phosphorylated protein expression.So we did the lab tests of these mechanisms.We innovatively used azacitidine and TKIs in the treatment of patients with AML maintenance, in order to reduce drug toxicity, enhance drug efficacy, improve patient prognosis and reduce the financial burden of patients.

Inclusion Criteria:

1. Patients with intermediate and high-risk AML who are diagnosed according to the 2016 WHO guidelines, aged ≥18 years;

2. Detect minimal residual disease(-) after induction therapy and consolidation therapy;

3. Eastern Cooperative Oncology Group (ECOG) performance status score 0-2;

4. The heart, pulmonary, liver and kidneys have sufficient organ functions:

   1. Cardiac color doppler ultrasound shows cardiac ejection fraction> 50%, heart function classification NYHA III/IV, no heart block or arrhythmia;
   2. Patients without severe restrictive/obstructive pulmonary disease;
   3. Liver function: total bilirubin (TBIL) < 2 times the upper limit of normal, alanine aminotransferase (ALT) and/or aspartate aminotransferase (AST) <2.5 times the upper limit of normal;
   4. Renal function: serum creatinine (Cr) < 1.5 times the upper limit of normal.

5. The patient and family members agree and sign an informed consent form.

Exclusion Criteria:

1. Patients with malignant tumors of other organs;

2. HCV positive; or HIV positive; or one of the following HBV test results:

   1. HBsAg positive;
   2. HBsAg negative, HBcAb positive and HBV DNA titer positive;

3. Pregnant and lactating women, and patients who have family planning during the enrollment period;

4. Patients considered to be unsuitable for enrollment by the investigator.

After the completion of the clinical trial, we will choose whether to disclose the result according to the relevant regulations of the Chinese Genetic Office.

According to the random number table