RecruitingPhase 1ProcedureOnvansertib for the Treatment of Recurrent or Refractory Chronic Myelomonocytic Leukemia and Myelodysplastic Syndrome/MPN Overlap NeoplasmsThis phase I trial evaluates the safety, effectiveness, and best dose of onvansertib for the treatment of patients with chronic myelomonocytic leukemia and Myelodysplastic syndrome/myeloproliferative neoplasm (MDS/MPN) overlap neoplasms that has come back (recurrent) or that does not respond to treatment (refractory). Onvansertib is a drug that binds to and inhibits an enzyme called PLK1, preventing cancer cell proliferation and causing cell death.