⁃ Confirmed diagnosis of acute myeloid leukemia (AML) according to world health organization (WHO) 2016 classification

⁃ Presence of FLT3-mutation(s) at inclusion: in case of FLT3-ITD, the ITD/wt ratio must be \> 0.05 ; in case of FLT3-TKD, the mutation must be at D835 or I836 position with a VAF \> 5% by NGS.

⁃ Subjects must be primary refractory or relapsed (R/R) to 1st line intensive chemotherapy (ICT) for AML. Hydroxyurea is allowed for the control of peripheral leukemic blasts in patients with leukocytosis.

‣ 3a. Primary refractory is defined as no CR or CRi after at least one course of ICT (including 7+3, gemtuzumab ozogamycin (GO)-based and CPX-351, including or not midostaurine) or two courses (maximum 4) of AZA and venetoclax 3b. Relapse after 1st line ICT for AML is defined as the first hematologic relapse with bone marrow blasts \>5% after one line of treatment for AML that includes at least one course of ICT (one line of treatment for AML can include induction, re-induction, consolidation, allogeneic HSCT and maintenance) 3c. Relapse after 1st line non intensive chemotherapy for AML is defined as the first hematologic relapse with bone marrow blasts \>5% after or during treatment by AZA venetoclax regardless of number of cycles 4. 1st line intensive treatment may or may not include previous treatment by tyrosine kinase inhibitor (TKI) except gilteritinib.

‣ 5\. Patients who never received oral azacitidine 6. Age ≥ 18 years 7. Adequate baseline organ function defined by the criteria below:

• adequate renal function as demonstrated by a creatinine clearance ≥ 50 ml/min; calculated by the Cockcroft gault formula or measured by 24-hours urine collection

• aspartate aminotransferase (AST) ≤ 2.5 × ULN

• alanine aminotransferase (ALT) ≤ 2.5× ULN

• bilirubin ≤ 1.5 × ULN

• adequate cardiac function with LVEF ≥45% 8. ECOG \< 3 (appendix 1) 9. Absence of any psychological, familial, sociological, or geographical conditions potentially hampering compliance with the study protocol and follow-up schedule 10. Patient is suitable for oral administration of study drug. 11. A female subject is eligible to participate if she is not pregnant and at least one of the following conditions applies: 9a. Not a woman of childbearing potential (WOCBP) as defined in post-menopausal (defined as at least 1 year without any menses) prior to Screening, or documented as surgically sterile (at least 1 month prior to Screening) 9b. WOCBP agrees to follow the contraceptive treatment starting at screening and continue throughout the study period, and for at least 180 days after the final study drug administration 12. Patient must be affiliated to the french social security (health insurance) 13. Signed written informed consent for the study 14. Female subject must agree not to breastfeed starting at screening and throughout the study period, and for 60 days after the final study drug administration.

• 15\. Female subject must not donate ova starting at screening and throughout the study period, and for 180 days after the final study drug administration.

• 16\. A male subject with female partner(s) of childbearing potential must agree to use contraception starting at screening and continue throughout the study period, for at least 120 days after the final study drug administration.

• 17\. Male subject must not donate sperm starting at screening and throughout the study period and for 120 days after the final study drug administration.