Chidamide in combination with venetoclax and azacitidine (VAC) were expected to improve remission rate of patients following to VA regimen treatment failure.

Venetoclax and azacitidine has become the standard first-line treatment for elderly/unsuitable AML patients who can't tolerate for intense chemotherapy.

However, a proportion of patients who were not able to achieve remission after failing to VA regimen and then were given the second cycle, and their rate of achieving remission was even lower. Chidamide down-regulates the expression of MCL and is expected to improve the remission rate further in combination with VA regimen.

Inclusion Criteria:

Patients with AML who are not suitable for intensive chemotherapy according to the WHO diagnosis: age ≥60 years or age <60 years but fulfil the following criteria;

1. Age 18 to 59 years;
2. Eastern Cooperative Oncology Group (ECOG) physical status score of 2 or 3;
3. Expected survival time ≥3 months;
4. Or fulfilment of severe cardiac, pulmonary, hepatic, or renal disease; (A) Presence of a cardiac history of congestive heart failure, or ejection fraction ≤ 50%, or presence of chronic stable angina; (B) Lung carbon monoxide diffusing capacity (DLCO) ≤ 65%, or first forced expiratory volume (FEV1) ≤ 65%; (C) Moderate hepatic impairment with total bilirubin > 1.5 to ≤ 3.0 x upper limit of normal (ULN); (D) Creatinine clearance ≥ 30 mL/min to < 45 mL/min;
5. Not received radiotherapy, treatment regimens other than the VA regimen, or haematopoietic stem cell transplantation within 4 weeks prior to enrolment;
6. Other comorbidities that, in the judgement of the physician, make the administration of intensive chemotherapy unsuitable;
7. Ability to understand and willingness to sign the informed consent for this trial;
8. The patient refuses intensive chemotherapy and has the willingness to accept non-intensive chemotherapy.

Exclusion Criteria:

1. Patients with a history of myeloproliferative neoplasms (MPN), including myelofibrosis, thrombocythemia, polycythaemia vera, chronic granulocytic leukemia (CML) with or without BCR-ABL1 translocation, and AML or acute promyelocytic leukemia (APL) with BCR-ABL1 translocation;
2. Patients with FLT3 mutations and who were treated with targeted agents (inclusion is possible if the use of specific targeted agents is discontinued);
3. Patients with less than 50% reduction of blasts after VA regimen;
4. Patients with active CNS involvement;
5. With prior treatment with chidamide;
6. Clinically uncontrolled active infections (including bacterial, fungal or viral infections) and organ hemorrhage;
7. Pregnant or lactating women;
8. Participation in any other clinical trial within 3 months prior to VAC regimen;
9. With other malignant tumours;
10. With uncontrolled mental disorders;
11. Any other condition that, in the opinion of the investigator, makes it inappropriate to participate in this trial.