Azacitidine + Lenalidomide Combo in the Elderly With Previously Treated AML & High-Risk MDS

This is an open label, single-center, and phase 2 study of the combination of azacitidine with lenalidomide in previously treated elderly patients with acute myeloid leukemia (AML) and/or high-risk myelodysplastic syndrome (MDS) who have failed prior therapy with either a demethylating agent and/or IMIDs. MDS includes Chronic Myeloid Leukemia (CML). Participants patients will receive azacitidine on the first 7 days followed by lenalidomide. Disease assessments with bone marrow examinations will be performed and if a complete response (CR); Complete remission with incomplete count recovery (CRi); partial response (PR); or stable disease (SD) is documented after 6 total cycles, participants will continue treatment until evidence of disease progression, provided they are tolerating treatment. Participants who have progressive disease or relapsed disease after the 6th cycle will be taken off the study, and participants with excessive toxicity at any time will be taken off the study. * CR = Less than 5% blasts with no Auer rods, absence of extramedullary disease, absolute neutrophil count (ANC) \> 1000/µL, platelets \> 100,000/µL, and independence of red cell transfusion) * CR with incomplete recovery (CRi) = all criteria of a CR with the exception of a platelet count less than 100,000/µL or residual neutropenia (\< 1000/µL). * PR = Meeting all hematologic criteria for CR with an allowance for 5% to 25% bone marrow blasts or decrease of pretreatment bone marrow blast percentage by ≥ 50%. * SD = Change in bone marrow aspirate blast count within 10% of baseline. * PD = Progressive / relapsed disease defined as reappearance of blasts in the blood or bone marrow blasts ≥ 5%, and development of extramedullary disease.