A Study to Investigate Fadraciclib (CYC065), in Subjects With Leukemia or Myelodysplastic Syndrome (MDS)

Phase 1 part of the study will consist of a dose-escalation and a dose-finding component. Phase 2 will enroll subjects AML, CLL, or MDS, into 7 groups: Group 1: Subjects with AML or MDS having marrow blasts over \> 10%, who have experienced an inadequate response or progression on venetoclax combinations with either HMAs or low dose Ara-C or similar venetoclax combinations Group 2: Fadraciclib: Subjects with AML or MDS relapsed/refractory having marrow blasts over \> 10% with FLT3, KIT, MAPK pathway (N and K RAS, BRAF, PTPN11, NF1) mutations after at least 1 line of prior therapy. Group 3: Fadraciclib: Subjects with CLL who have progressed on 2 or more lines of therapy, including a Bruton's tyrosine kinase (BTK) inhibitor and venetoclax. Group 4: Fadraciclib plus azacitidine: Subjects with AML or MDS who have progressed after therapy with an HMA. Group 5: Fadraciclib plus venetoclax: Subjects with AML or MDS who have progressed after therapy with venetoclax. Group 6: Fadraciclib plus venetoclax: Subjects with CLL or small lymphocytic lymphoma (SLL) who have progressed after therapy with venetoclax. Group 7: Basket cohort: Leukemia types suspected to have a related mechanism of action such as MCL1, or MYC amplification/over-expression not included in previous groups