A Phase II Study of Cladribine and Low Dose Cytarabine in Combination With Venetoclax, Alternating With Azacitidine and Venetoclax, in Patients With Higher-risk Myeloproliferative Chronic Myelomonocytic Leukemia or Higher-risk Myelodysplastic Syndromes With Excess Blasts

Primary Objectives: * To determine the efficacy, safety and tolerability of the combination of cladribine, cytarabine and venetoclax in higher-risk MDS with excess blasts and higher-risk CMML. * MDS relapsed cohort (Cohort A, N=20): MDS with Int-2 or High risk IPSS and \>5% blasts with no response after 6 cycles of azacitidine, decitabine, guadecitabine, CC-486 or ASTX727 (decitabine/cedazuridine) or relapse or progression after any number of cycles * CMML relapsed cohort (Cohort B, N=10): CMML 1 or 2 with no response after 6 cycles of azacitidine, decitabine, guadecitabine, CC-486 or ASTX727…