Inclusion Criteria:

          1. Males and females ≥18 years of age

          2. Life expectancy of at least 3 months

          3. Eastern Cooperative Oncology Group (ECOG) Performance Status of ≤2

          4. Cytomorphology based confirmed diagnosis of MDS or AML with the following
             characteristics.

             Phase 1 Dose Escalation (Monotherapy)

             • AML (primary or secondary, including treatment-related) after failing at least 1
             standard treatment (may include chemotherapy, re induction therapy or stem cell
             transplantation).

             OR

             • High-risk R/R MDS that are considered resistant/refractory following at least 2 to 3
             cycles of hypermethylating agent (HMA) or evidence of early progression

             Phase 1b (Combination Therapy) Doublet Arm: CA-4948 + AZA

             Patients with:

               -  International Prognostic Scoring System- revised (IPSS- R) High, high risk
                  myelodysplastic syndrome (hrMDS)

               -  HMA and ventoclax naïve, and ineligible for intensive chemotherapy

             Doublet Arm: CA-4948 + Venetoclax

             Patients with:

               -  R/R AML or hrMDS, after first line therapy

               -  Venetoclax naïve

             Phase 2a Dose Expansion (Monotherapy)

             Patients with:

               -  R/R AML, FLT3-ITD mutant AML patients after failing at least 1 and maximal 3
                  pretreatments, including a FLT3 inhibitor FLT3 inhibitor

               -  R/R AML with FLT3 WT, after failing 1 to 3 pretreatments. Desired enrichment for
                  expression of spliceosome mutations (SF3B1, U2AF1, SRSF2, ZRSR1)

               -  R/R hrMDS with spliceosome mutations of SF3B1 and U2AF1 only resistant/refractory
                  to HMA; ineligible for intensive chemotherapy. maximal 3 pretreatments

               -  R/R hrMDS without SF3B1 or U2AF1spliceosome mutations (can have SRSF2 or ZRSR2
                  mutations); resistant/refractory to r/r to HMA; ineligible for intensive
                  chemotherapy, maximal 3 pretreatments

          5. Acceptable organ function at screening

          6. Ability to swallow and retain oral medications

          7. Negative serum pregnancy test in women of childbearing potential

          8. Women of childbearing potential and men who partner with a woman of childbearing
             potential must agree to use highly effective contraceptive methods for the duration of
             the study and for 90 days after the last dose of CA-4948

          9. Willing and able to provide written informed consent and comply with the requirements
             of the trial

         10. Able to undergo serial bone marrow sampling and peripheral blood sampling

        Exclusion Criteria:

          1. Diagnosed with acute promyelocytic leukemia (APL, M3)

          2. Has known active central nervous system (CNS) leukemia

          3. Allogeneic hematopoietic stem cell transplant (Allo-HSCT) within 60 days of the first
             dose of CA-4948, or clinically significant graft-versus-host disease (GVHD) requiring
             ongoing up titration of immunosuppressive medications prior to start of CA-4948

          4. Chronic myeloid leukemia (CML)

          5. Any prior systemic anti-cancer treatment such as chemotherapy, immunomodulatory drug
             therapy, etc., received within 14 days prior to start of CA-4948. Localized radiation
             or surgical resection of skin cancers allowed.

          6. Use of any investigational agent within 28 days or 5 half-lives, whichever is shorter,
             prior to start of CA-4948

          7. Presence of an acute or chronic toxicity resulting from prior anti-cancer therapy,
             with the exception of alopecia that has not resolved to Grade ≤1 within 7 days prior
             to start of CA-4948

          8. Known allergy or hypersensitivity to any component of the formulation of CA-4948

          9. Major surgery, other than diagnostic surgery, <28 days from the start of CA-4948;
             minor surgery <14 days from the start of CA-4948

         10. Known hypersensitivity to azacitidine or mannitol, as stated per label (Phase 1b only)

         11. Patients with active advanced malignant solid tumors

         12. Known to be human immunodeficiency virus (HIV) positive or have an acquired
             immunodeficiency syndrome-related illness

         13. Hepatitis B virus (HBV) DNA positive or Hepatitis C virus (HCV) infection <6 months
             prior to start of CA-4948 unless viral load is undetectable, or HCV with cirrhosis

         14. Uncontrolled or severe cardiovascular disease

         15. Gastrointestinal disease or disorder that could interfere with the swallowing, oral
             absorption, or tolerance of CA-4948

         16. History of other invasive malignancy, unless definitively treated with curative
             intent, provided it is deemed to be at low risk for recurrence by the treating
             physician

         17. Pregnant or lactating female

         18. Systemic fungal, bacterial, viral, or other infection that is not controlled

         19. Any other severe, acute, or chronic medical, psychiatric or social condition, or
             laboratory abnormality that may increase the risk of trial participation or CA-4948
             administration