A Study of CFI-400945 With or Without Azacitidine in Patients With AML, MDS or CMML

Inclusion Criteria: 1. Patients must be \>18 years of age 2. For Parts 1A and 1B, the following malignancy types will be included: 1. Relapsed or refractory AML. 2. MDS, after prior hypomethylating agents. 3. CMML, with progressive disease/lack of response after hypomethylating agents For Parts 1A and 1B, Patients may have relapsed or refractory disease. 3. For Parts 2A and 2B, the following malignancy types will be included: 1. Relapsed or Refractory AML. 2. MDS patients should be limited to high risk disease 3. MDS or CMML should be previously untreated and patients with AML may have relapsed or refractory disease; 4. Have clinically acceptable laboratory screening results (i.e., clinical chemistry, hematology, and urinalysis) within certain limits per protocol. 5. Have an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1. Exclusion Criteria: 1. Patients who have received investigational therapy, radiotherapy, immunotherapy, monoclonal antibodies, or chemotherapy within 14 days or 5 half-lives (whichever is shorter) 2. Allogeneic or autologous transplant for AML with infusion of stem cells within 90 days before Cycle 1 Day 1, or on active immunosuppressive therapy for graft-versus-host disease (GVHD) or GVHD prophylaxis within 2 weeks of Cycle 1 Day 1. 3. Any Grade ≥ 2 persistent non-hematological toxicity related to allogeneic transplant, such as those requiring systemic immunosuppressive therapy.