This Phase 3, randomized, open-label, parallel-group multicenter study of the efficacy and safety of guadecitabine in adults with previously treated 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 subject participation will vary, and subjects may continue to receive treatment for as long as they continue to benefit.