Patients with promyelocytic leukemia (French-American-British [FAB] M3) Patients with MDS must have been diagnosed as MDS by WHO (4th edition) or French-American-British (FAB) classification RAEB-t per French-American-British (FAB) classification (20% to 30% BM blasts) Acute promyelocytic leukemia (APL, French-American-British (FAB) subtype M3), according to WHO classification. Patients with t(15;17) karyotypic abnormality or acute promyelocytic leukemia (French-American-British [FAB] class M3-AML) Confirmed diagnosis of MDS according to the French-American-British (FAB) criteria. Subjects with MDS must have intermediate, high, or very high risk IPSS-R scores and cytopenia of at least one lineage. Patients with t(15;17) karyotypic abnormality or acute promyelocytic leukemia (French-American-British [FAB] class M3-AML) Patients with cytologically confirmed and documented de novo, secondary or therapy-related AML, excluding acute promyelocytic leukaemia (APL, French-American British M3 classification): Acute promyelocytic leukemia (M3 leukemia, per French-American-British classification) Subjects with French American British (FAB) M3 (t (15; 17) (q22; q21) [promyelocytic leukemia (PML)-retinoic acid receptor (RAR) alpha]) are not eligible Histologically confirmed diagnosis of a myelodysplastic syndrome, meeting criteria for any subtype in the French-American-British (FAB) or World Health Organization (WHO) classification systems with any International Prognostic Scoring System (IPSS) score Diagnosis of acute promyelocytic leukemia (APL), AML - M3 by French American British (FAB) classification based on morphology, immunophenotype, molecular, or cytogenetics studies Acute promyelocytic leukemia (French-American-British [FAB] M3 AML) Diagnosis of acute promyelocytic leukemia (APL, French-American-British [FAB] classification M3 or WHO classification of APL with t (15;17)(q22;q12), promyelocytic leukemia protein [PML]/retinoic acid receptor alpha [RARa] and variants) AML, any French- American- British (FAB) subtype except M3, with confirmed mutation in the NPM1 gene Patients with acute promyelocytic leukemia (French-American-British [FAB] class M3 AML) Diagnosis of MDS according to World Health Organization (WHO) criteria or French-American-British (FAB) classification that must be confirmed by bone marrow (BM) aspirate and/or biopsy within 6 weeks prior to Screening. Patients with acute promyelocytic leukemia confirmed with t(15;17) (French-American-British Classification [FAB] subtype M3 and M3 variant) Subjects with untreated AML, if not candidates for standard induction chemotherapy or with poor risk AML (i.e. preceding myelodysplastic syndromes [MDS], myeloproliferative syndromes, leukemia due to cytotoxic chemotherapy for another condition, adverse cytogenetics or complex karyotype), acute promyelocytic leukemia (French-American-British [FAB] M3) is excluded Subject has French-American-British classification (FAB) type M3 leukemia (acute promyelocytic leukemia) or identification of t(15;17). Suspected or proven acute promyelocytic leukemia (French-American-British (FAB) M3) based on morphology, immunophenotype, molecular assay, or karyotype; AML associated with t(9;22) karyotype, biphenotypic acute leukemia or AML with previous hematologic disorder such as chronic myelogenous leukemia or myeloproliferative neoplasms. AML French-American-British (FAB) M3 in first complete remission (CR1) Patients must have morphologically confirmed newly diagnosed acute myelogenous leukemia (AML) with blood or bone marrow disease; patients with only extramedullary disease in the absence of bone marrow or blood involvement are eligible; note: this protocol uses World Health Organization (WHO) diagnostic criteria for AML; patients with acute promyelocytic leukemia (APL, French-American-British Classification [FAB], M3) or blastic transformation of chronic myelogenous leukemia (CML) are not eligible Morphologically confirmed diagnosis of MDS or nonproliferative CMML (that is, with white blood cells [WBC] <20,000 per microliter [/mcL]) or low blast AML based on 1 of the following: French American British (FAB) Classifications: Subjects must have relapsed/refractory AML by world health organization (WHO) classification for which no standard therapies are available or anticipated to result in a durable remission. French- American- British system (FAB) subtype M3 will be excluded. Participant has acute promyelocytic leukemia (French-American-British Class M3 AML). Patients with acute promyelocytic leukemia (French-American-British Cooperative group [FAB] M3) Subjects with acute promyelocytic leukemia (APL) - French-American-British Cooperative group (FAB) M3 (t(15;17)(q22;q21)[promyelocytic leukemia (PML)-retinoic acid receptor (RAR)]) are not eligible Acute promyelocytic leukaemia (French-American-British (FAB) classification subtype M3). Acute promyelocytic leukemia (French-American-British [FAB] M3 AML) Diagnosis of myelodysplastic syndrome (MDS) confirmed within 10 weeks prior to study entry according to World Health Organization (WHO) or French-American-British (FAB) criteria; patients are either not eligible for or choose not to proceed with a stem cell transplant Confirmed diagnosis of MDS using the World Health Organization (WHO) classification or a diagnosis of WHO myelodysplastic/ myeloproliferative neoplasm (MDS/MPN) or MDS refractory anemia with excess blast in transformation (RAEB-t) by French American British (FAB) classification (acute myeloid leukemia [AML] with 20-30% myeloblasts by WHO classification) Patients with known acute promyelocytic leukemia (French-American-British class M3-AML) Acute promyelocytic leukemia (French-American-British Class M3 AML). Diagnosis of acute promyelocytic leukemia (APL, French-American-British [FAB] classification M3 or World Health Organization [WHO] classification of APL with t[15;17][q22;q12]), (progressive multifocal leukoencephalopathy [PML]/retinoic acid receptor alpha [RARa] and variants) MDS by World Health Organization (WHO) or French-American-British (FAB) classification have diagnosis of AML French-American-British (FAB) classification (FAB) M3 (acute promyelocytic leukemia (APL)) Confirmed MDS by bone marrow biopsy according to World Health Organization (WHO) or French-American-British (FAB) criteria All categories of AML will be included except for acute promyelocytic leukemia (APL) (AML-M3 as defined by 1976 French-American-British [FAB] classification, or APL with t(15;17)(q22;q12); PML-RARA as defined by the revised 2008 World Health Organization [WHO] classification of myeloid neoplasms and acute leukemias), acute megakaryocytic leukemia (AML-M7 type as per FAB or AML [megakaryoblastic] with t(1;22)(p13;q13); RBM15-MKL1 as per WHO 2008 revised classification) and acute leukemias of ambiguous lineage (as per WHO 2008 revised classification), undergoing 7 + 3 remission IC with cytarabine and an anthracycline (daunorubicin or idarubicin); all cases have to be histopathologically confirmed by a diagnostic bone marrow biopsy; use of granulocyte colony-stimulating factor (G-CSF) for any indication must have been discontinued at least 7 days prior to entry into the study Documented diagnosis of MDS (MYELODYSPLASTIC SYNDROMES), classified according to FAB (FRENCH-AMERICAN BRITISH) classification criteria Acute myelogenous leukemia (AML (ACUTE MYELOID LEUKEMIA) - FAB (FRENCH-AMERICAN-BRITISH) classification: ? 30% blasts in bone marrow). Subjects known to have ? 30% blasts are not eligible for inclusion in this study. Recognizing limitations of blast cell quantification, this protocol will allow subjects with pre-enrollment (screening/baseline) bone marrow blast counts up to 33% to be considered for inclusion.