• Age . 18 years.

• ECOG performance status of \< 2.

• Relapsed or refractory AML or myeloid mixed-phenotype acute leukemia (MPAL) with NPM1mt, or KMT2Ar, or NUP98r.

• WBC must be below 25,000/ ƒÊL at time of enrollment. Patients may receive cytoreduction prior to enrollment.

• Baseline ejection fraction must be \> 40%.

• Adequate hepatic function (total bilirubin \< 2x upper limit of normal (ULN) unless increase is due leukemic involvement (\<2.5 ULN), unless due to ongoing hemolysis or Gilbert's syndrome and AST and/or ALT \< 3x ULN unless considered due to leukemic involvement, in which case direct bilirubin or AST and/or ALT \< 5x ULN will be considered eligible).

• Adequate renal function with an estimated glomerular filtration rate . 50 mL/min (using Cockcroft-Gault) unless related to disease.

• Able to swallow pills.

• Patient or parent/guardian is willing and able to provide informed consent.

⁃ In the absence of rapidly proliferative disease, the interval from prior treatment to time of initiation will be at least 14 days for cytotoxic or non-cytotoxic (immunotherapy agent(s), or an interval of 5 half-lives of the prior therapy, whichever is longer. Oral hydroxyurea and/or cytarabine (up to 1 g/m2) for patients with rapidly proliferative disease is allowed before the start of study therapy, as needed, for clinical benefit and after discussion with the PI.

⁃ Concurrent therapy for central nervous system (CNS) prophylaxis or continuation of therapy for controlled CNS disease is permitted.

⁃ Women of childbearing potential must agree to adequate methods of contraception during the study and at least 7 months for females and 4 months for males after the last treatment. Males must be surgically or biologically sterile or agree to use an adequate method of contraception during the study and at least 4 months after the last treatment.