Additional Study Information: The purpose of this study is to determine if oral azacitidine (CC-486) is safe and effective as maintenance therapy in continuing the response patients had with their last acute myeloid leukemia (AML) treatment and improving the quality of that response. Currently, there is no standard treatment to maintain or improve patient response and patients are usually just observed or watched. Their doctor may decide to follow them closely through regular physical exams and tests, but without more treatment. Since there is possibility that the disease may come back (relapse), the goal is to search for new treatments that may reduce the risk for relapse or at least to prolong the time before disease relapse.