This Phase 3, randomized, open-label, parallel-group multicenter study of the efficacy and safety of guadecitabine in adults with previously treated acute myeloid leukemia (AML) will be conducted in approximately 20 countries. There will be a 14-day screening period, a treatment period, a safety follow-up visit, and a long-term follow-up period. The study is expected to last approximately 2 years. Duration of individual participant participation will vary, and participants may continue to receive treatment for as long as they continue to benefit.~Approximately 404 participants from approximately 100 study centers will be randomly assigned to either guadecitabine or treatment choice (TC) in a 1:1 ratio (approximately 202 participants per group). TC is as follows:~High intensity: intermediate or high dose cytarabine (HiDAC); mitoxantrone, etoposide, and cytarabine (MEC); or fludarabine, cytarabine, G-CSF, +/- idarubicin (FLAG/FLAG-Ida).~Low intensity: low dose cytarabine (LDAC), decitabine, or azacitidine.~Best Supportive Care (BSC).~Guadecitabine will be given subcutaneous (SC) at a dose of 60 microgram per meter square (mg/m^2) in 28-day cycles. In Cycle 1, guadecitabine will be given for 10 days on Days 1-5 and Days 8-12. Cycle 2 will be either the 5-day regimen (Days 1-5) or 10-day regimen (Days 1-5 and 8-12) based on assessment of disease response and hematologic recovery at the end of Cycle 1. In subsequent cycles, guadecitabine treatment will be for 5 days only (Days 1-5).
Multicenter, randomized, open-label, parallel-group study of guadecitabine vs treatment choice (TC). Participants will be randomly assigned in a 1:1 ratio to either guadecitabine or TC. TC options include the 8 high or low intensity, locally available regimens below; or Best supportive Care (BSC) alone:~High intensity (intermediate or high dose cytarabine [HiDAC]; mitoxantrone, etoposide, and cytarabine [MEC]; or fludarabine, cytarabine, granulocyte colony stimulating factor [G-CSF], +/- idarubicin [FLAG/FLAG-Ida]).~Low intensity (low dose cytarabine [LDAC], decitabine, or azacitidine).~BSC.