This is a multicenter, randomized, Phase 3 study ("SEAMLESS") comparing two drug regimens (arms) as the front-line treatment of elderly patients aged 70 years or older with newly diagnosed acute myeloid leukemia (AML) who are not candidates for intensive induction chemotherapy. In Arm A, sapacitabine is administered in alternating cycles with decitabine, and in Arm C decitabine is administered alone. The primary efficacy endpoint is overall survival. The study is designed to demonstrate an improvement in overall survival of Arm A versus Arm C.