Inclusion Criteria:

* Participants is ≥ 18 years of age at the time of signing the Informed Consent Form (ICF).
* Participants must understand and voluntarily sign an ICF prior to any study-related assessments/procedures being conducted.
* Participants are willing and able to adhere to the study visit schedule and other protocol requirements.
* Participants with histologically or cytologically confirmed AML including de novo AML or secondary AML transformed from MDS according to 2022 World Health Organization (WHO) criteria classification, or with histologically or cytologically confirmed HR-MDS.
* R/R AML and R/R HR-MDS who have failed or are ineligible for all available therapies which may provide clinical benefit.
* Participants must have the following screening laboratory values:

* Total white blood cell count (WBC) \< 25 x 10\^9/L prior to the first dose of the study drug.
* Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤ 3.0 × upper limit of normal (ULN), unless considered due to extensive leukemic liver involvement, in which case AST and ALT can be ≤ 5.0 x ULN.
* Serum total bilirubin ≤ 1.5 x ULN, unless considered due to Gilbert's syndrome, in which case serum total bilirubin \< 3 x ULN.
* Estimated serum creatinine clearance of ≥ 60 mL/min using the Cockcroft-Gault equation. Measured creatinine clearance from a 24-hour urine collection is acceptable if clinically indicated.
* International normalized ratio (INR) ≤ 1.5 x ULN and active partial thromboplastin time (aPTT) ≤ 1.5 x ULN.
* Life expectancy ≥ 12 weeks.
* Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 to 2.
* Female Participants of child-bearing potential must have a negative serum or urine pregnancy test at screening and at pre-dose on Cycle 1 Day 1 (C1D1).

Exclusion Criteria:

* Participants with acute promyelocytic leukemia (APML).
* Participants with known leukemic involvement in central nervous system (CNS).
* Receipt of anticancer medications/therapies within 5 half-lives or 28 days before the first administration of the study drug.
* Participants with unresolved clinically significant non-hematologic toxicities of ≥ Grade 2 AE from prior therapies with exception of residual alopecia.
* Participants with chronic graft versus host disease (GVHD) requiring systemic immunosuppressive therapy.
* Participants with active malignancies other than AML or MDS.
* Participants who have undergone major surgery ≤ 4 weeks prior to the first dose of the study drug.
* Participants with immediately life-threatening, severe complications of leukemia such as disseminated/uncontrolled infection (bacterial and/or fungal), uncontrolled bleeding, and/or uncontrolled disseminated intravascular coagulation.
* Participants with known chronic, active infection of hepatitis B virus (HBV), hepatitis C virus C (HCV), human immunodeficiency virus (HIV).
* Participants unable to swallow oral medications, or Participants with clinically significant diarrhea, vomiting or malabsorption felt limited absorption of orally administered medications.
* Participants with any other significant medical conditions, any other conditions, laboratory abnormality, or psychiatric illness which place the Participants at unacceptable risk if he/she were to participate in the study or that would hamper the Participants understanding of the study, or would prevent the Participant from complying with the study.
* Medications or supplements that are known to be strong and moderate inhibitors or inducers of CYP450 isozyme 3A4 (CYP3A4) and/or P-glycoprotein (P-gp), or strong inhibitors or inducers of CYP450 isozyme 2C8 (CYP2C8) within 14 days or 5 half-lives, whichever is shorter, before the first dose of study drug.
* Pregnant or lactating women.