Inclusion Criteria:

          -  Patients must have one of the following disease characteristics:

               -  Therapy-related myeloid neoplasm (t-MN) age >= 18 years

                    -  Patients must have received cytotoxic chemotherapy, radiation, or a drug
                       known to affect the properties of deoxyribonucleic acid (DNA) or cell
                       growth, prior to current diagnosis of therapy-related myeloid neoplasm
                       (t-MN); this broad definition is meant to include any prior therapy with
                       chemicals that affect DNA replication, DNA integrity, or DNA structure, or
                       chemicals that alter cell growth; this includes traditional cytotoxic
                       chemotherapy, newer immunologic agents that have been shown to have
                       cytotoxic activities in addition to immunosuppressive functions, and other
                       chemicals; note that patients with primary AML could be diagnosed with a t-
                       MN if morphology/cytogenetic analysis clearly indicated that the second
                       process is not a relapse of the original disease

               -  AML arising from an antecedent hematological disorder age >= 18 years

               -  De novo AML in patients age >= 60 years

               -  Relapsed and/or refractory AML >= 18 years

          -  Eastern Cooperative Oncology Group (ECOG) performance status 0-2

          -  Female patients of childbearing potential must have a negative serum pregnancy test
             within 2 weeks prior to enrollment

          -  Male and female patients must use an effective contraceptive method during the study
             and for at least 6 months after study treatment

          -  Patients must be at least 2 weeks from major surgery, radiation therapy, participation
             in other investigational trials and must have recovered from clinically significant
             toxicities of these prior treatments

          -  Ability to understand and willingness to sign the informed consent form

        Exclusion Criteria:

          -  Concomitant chemotherapy, radiation therapy, or immunotherapy other than as specified
             in this protocol

          -  Diagnosis of acute promyelocytic leukemia (APL)

          -  Use of investigational agents/any anticancer therapy within 2 weeks before study entry
             with the exception of hydroxyurea (note: for patients with hyperleukocytosis [white
             blood cell (WBC) > 20,000/uL], hydroxyurea [and leukapheresis, if clinically
             indicated] will be initiated and these patients will receive 5-azacytidine when the
             WBC count has decreased to =< 20,000/uL; hydroxyurea can be overlapped with
             5-azacytidine in selected cases, after consultation with the study chair; hydroxyurea
             must be discontinued before the initiation of the HiDAC/mitoxantrone chemotherapy)

          -  Prior treatment with 5-azacytidine followed immediately by HiDAC and mitoxantrone as
             proposed in this study (note: prior therapy with 5-azacytidine or decitabine or HiDAC
             or mitoxantrone would be allowed-in patients with relapsed/refractory disease- unless
             the prior therapy was identical to the schema/schedule proposed in this study)

          -  Active second cancer other than specified; active cancer refers to cancer that
             requires systemic chemotherapy or biological therapy within 6 months of the study
             entry; patients who have received only hormonal therapy in the neoadjuvant or adjuvant
             setting in the past 6 months may participate in this study

          -  Have any other severe concurrent disease, or have a history of serious organ
             dysfunction (e.g. uncontrolled or severe cardiovascular disease, diabetes, pulmonary
             disease, infection, psychiatric illness) that may in the judgment of the treating
             physician/ principal investigator place the patient at undue risk to undergo treatment

          -  Pregnant or lactating patients

          -  Any significant concurrent illness that would, in the judgment of the treating
             physician/principal investigator, compromise patient safety or compliance, or study
             participation