Lenalidomide After Allo-Hematopoietic Cell Transplant (HCT) in Acute Myelogenous Leukemia (AML) and Myelodysplastic Syndromes (MDS) Subjects With Minimal Residual Disease

Inclusion Criteria: 1. Subjects must be at least 18 years of age; 2. Subjects must be post-allogeneic transplant from any donor source; 3. Subjects must have either: 1. High risk CD34+ AML (de novo or secondary, and any WHO 2008 classification excluding acute promyelocytic leukemia). High risk AML is defined as (a) disease status beyond complete remission (CR) #1 at transplant or (b) treatment related AML or (c) presence of adverse cytogenetics including inv(3); t(3;3); t(6;9); t(v;11); -5 or del(5q); -7; abnl(17p) or complex karyotype; or 2. High risk CD34+ MDS (WHO 2008 classification). High risk is defined as (a) blast count ≥5% at the time of transplant or (b) treatment related MD or (c) presence of adverse cytogenetics including -7/del7q or complex karyotype; 4. For AML subjects, they must have a documented CR within 45 days prior to allo-HCT; 5. For MDS subjects, they must have \< 20% myeloblasts in the bone marrow within 45 days prior to allo-HCT; 6. Subject Karnofsky performance status must be ≥ 70; 7. Subjects must be platelet transfusion independent (Platelet transfusion independence is defined as 7 days or greater without a platelet transfusion); 8. Neutrophil count ≥ 1.0 thou/mm3 and platelet count ≥ 30 thou/mm3; 9. Subjects must have total bilirubin ≤ 2 mg/dL; 10. Subjects must have serum AST and ALT levels ≤ 2.5 times upper limit of normal; 11. Subjects must have serum creatinine \< 2.5 times upper limit of normal and a calculated creatinine clearance \> 30 ml/min by Cockcroft-Gault formula (see Appendix I: Cockcroft-Gault Creatinine Clearance Calculation); 12. All study participants who will receive lenalidomide based on the CD34+ chimerism testing must be registered into the mandatory Revlimid REMS® program, and be willing and able to comply with the requirements of the REMS® program; 13. Females of child-bearing potential (i.e., women who are premenopausal or not surgically sterile) may participate, provided they meet the following conditions: a) Females of reproductive potential must adhere to the scheduled pregnancy testing as required in the Revlimid REMS® program; and 14. Written, voluntary informed consent, willingness, and ability to comply with all study procedures. Exclusion Criteria: 1. CD34- AML or MDS; 2. Inability to give informed consent; 3. Uncontrolled active infection(s) requiring intravenous antibiotics; 4. Known or suspected hypersensitivity to lenalidomide; 5. Grade II-IV acute GVHD or extensive GVHD; 6. Not able to swallow the lenalidomide capsule as a whole; 7. Female subjects who are pregnant or nursing.