Venetoclax and Sequential Busulfan, Cladribine, and Fludarabine Phosphate Before Donor Stem Cell Transplant in Treating Patients With Acute Myelogenous Leukemia or Myelodysplastic Syndrome

This randomized phase II trial studies how well venetoclax and sequential busulfan, cladribine, and fludarabine phosphate before donor stem cell transplant work in treating patients with acute myelogenous leukemia or myelodysplastic syndrome. Giving chemotherapy before a donor peripheral blood stem cell transplant helps kill cancer cells in the body and helps make room in the patient's bone marrow for new blood-forming cells (stem cells) to grow. When the healthy stem cells from a donor are infused into a patient, they may help the patient's bone marrow make more healthy cells and platelets and may help destroy any remaining cancer cells.