A Study Being Conducted at Multiple Locations to Compare Safety and Efficacy of Three Different Regimens; (1) High-Dose Lenalidomide; (2) Lenalidomide + Azacitidine; or (3) Azacitidine in Subjects ≥ 65 Years With Newly-Diagnosed Acute Myeloid Leukemia

Based on IWG response criteria for AML. Complete remission (CR), morphologic complete remission (CR) was defined as < 5% bone marrow blasts, an absolute neutrophil count ≥ 1 x 10^9/L, platelets ≥100 x 10^9/L, and transfusion independence (no transfusions for 1 week prior to each assessment). No duration of these findings is required for confirmation of this response.

Morphologic CR with incomplete blood count recovery (CRi) was defined as a morphologic complete remission but the ANC count may be <1 x 10^9/L and/or the platelet count may be <100 x 10^9/L. Because of a high rate of discontinuation in one of the investigational cohorts, secondary endpoints were not analyzed.

Duration of remission was defined as the time from the date of CR or CRi until relapse. Because of a high rate of discontinuation in one of the investigational cohorts, secondary endpoints were not analyzed.

The CRc response category is comprised of the subset of participants who had abnormal cytogenetics at baseline and subsequently achieved CR during treatment in conjunction with a reversion to a normal karyotype. For the primary definition of CRc, a normal karyotype is defined as no clonal abnormalities after review of at least 10 metaphases using conventional cytogenetic techniques. Cytogenetic complete remission rate (CRc) 1) CR criteria met AND 2) Abnormal karyotype present at baseline AND 3) Reversion to normal karyotype at time of CR (based on ≥ 10 metaphases), where date of cytogenetic sample = date of BM sample used for the CR assessment. Because of a high rate of discontinuation in one of the investigational cohorts, secondary endpoints were not analyzed.

Morphologic complete remission (CR) is defined as a leukemia-free state defined as less than 5% blasts in a one marrow aspirate with spicules and with at least 200 nucleated cells (there should be no blasts with auer rods) and ANC of ≥ 1 x 10^9/L, a platelet count ≥ 100 x 10^9/L, no transfusions for 1 week prior to each assessment. No duration of these findings is required for confirmation of this response. Morphologic complete remission with incomplete blood count recovery was defined as a morphologic complete remission but the ANC may be < 1 x 10^9/L and/or the platelet count may be < 100 x 10^9/L. Partial remission was defined as an ANC > 1 x 10^9/L and platelet count ≥ 100 x 10^9/L with a > 50% decrease in the percentage of bone marrow blasts to 5% to 25% (a blast count value of ≤ 5% may also be considered a partial remission if auer rods are present). Because of a high rate of discontinuation in one of the investigational cohorts, secondary endpoints were not analyzed.

PFS is defined as the time from randomization to the first observation of documented disease progression or death from any cause whichever occurred first. Because of a high rate of discontinuation in one of the investigational cohorts, secondary endpoints were not analyzed.

EFS was defined as the interval from the date of randomization to the date of treatment failure, progressive disease, relapse after CR or CRi, or death from any cause, whichever occurred first. Because of a high rate of discontinuation in one of the investigational cohorts, secondary endpoints were not analyzed.

RFS is defined only for subjects that achieve CR and CRi and is measured as the interval from that date to the date of disease relapse, death from any cause, whichever occurs first, censoring at the last visit date for subjects alive in continuous CR/CRi. Because of a high rate of discontinuation in one of the investigational cohorts, secondary endpoints were not analyzed.

30-day mortality rate was defined as death from any cause within 30 days after first dose.

TEAEs were defined as those events that started on or after the first day of study drug up until 28 days after the last dose of study drug; Serious AE (SAE) = any AE which results in death; is life-threatening; requires inpatient hospitalization or prolongation of existing hospitalization; results in persistent or significant disability; is a congenital anomaly/birth defect; constitutes an important medical event. Severity of AEs were graded based upon the participants symptoms according to the Common Terminology Criteria for Adverse Events (CTCAE, Version 4.0); and according to the scale: Grade (Gr) 1 = Mild - transient or mild discomfort; no medical intervention required; Grade 2 = Moderate - mild to moderate limitation in activity; Grade 3 = Severe; Grade 4 = Life threatening; Grade 5 = Death

Second primary malignancies were monitored as events of interest and reported as serious adverse events regardless of the treatment arm the participant was enrolled in.