Subjects who are able and willing to give written informed consent

          -  Documented primary or secondary AML, as defined by the WHO criteria (2008), by
             histopathology refractory to previous induction chemotherapy and/or relapsed after
             achieving remission with a prior chemotherapy and who are not candidates for other
             available therapy likely to confer clinical benefit.

          -  For Phase 2a only: in addition to inclusion criteria 2 above, patients must have a
             FLT3 mutation of any type

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

          -  In the absence of rapidly progressing disease, the interval from prior treatment to
             time of FF-10101-01 administration should be at least 14 days for cytotoxic agents
             other than hydroxyurea, at least 5 half-lives for non-cytotoxic agents, and 14 days
             for monoclonal antibody therapies. Hydroxyurea may be continued for a maximum of 14
             days from the start of FF-10101-01 dosing, through Cycle 1 Day 14, with a maximal dose
             of 5 grams/day

          -  Persistent chronic clinically significant toxicities from prior chemotherapy or
             surgery must be ≤Grade 2

          -  If subject has had a hematopoietic stem cell transplant, subject must be ≥60 days
             post-transplant with no clinically significant GVHD requiring systemic therapy

          -  Alanine aminotransferase (ALT) and/or aspartate aminotransferase (AST) ≤3 times the
             upper limit of normal and total bilirubin of ≤1.5x the upper limit of normal. If total
             bilirubin is equal to or exceeds 1.5x the upper limit of normal, the subject can still
             be included if direct bilirubin is ≤1.5x the upper limit of normal

          -  Calculated creatinine clearance of ≥60 mL/min

          -  Female subjects of childbearing potential and sexually mature male subjects must agree
             to use a medically accepted method of contraception other than an oral contraceptive
             for the duration of the study.

        Exclusion Criteria:

          -  Subjects diagnosed with acute promyelocytic leukemia

          -  Subjects with Bcr-Abl positive leukemia (chronic myelogenous leukemia in blast crisis)

          -  Subjects with clinically active CNS leukemia

          -  Subjects with major surgery within 28 days prior to the first administration of
             FF-10101-01

          -  Subjects with radiation therapy within 28 days prior to the first administration of
             FF-10101-01

          -  Subjects with active malignant disease requiring therapy other than AML or
             myelodysplastic syndrome with transformation into AML

          -  Subjects with an active uncontrolled infection

          -  Subjects with a medical condition, serious intercurrent illness, or other circumstance
             that, in the Investigator's judgment, could jeopardize the subject's safety as a study
             subject, or that could interfere with the study objectives

          -  Subjects known to have human immunodeficiency virus infection, or who have active
             hepatitis B or C infection as determined by serological testing

          -  Subjects with congestive heart failure, New York Heart Association (NYHA) Class 3 or
             4, or subjects with a past history of congestive heart failure NYHA Class 3 or 4 and
             in whom echocardiogram or multiple gate acquisition (MUGA) scan performed within 3
             months prior to screening or at screening showed a LVEF <40%

          -  Female subjects who are pregnant or breast feeding

          -  Subjects on 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statins) or
             other drugs known to have muscle toxicity

          -  Subjects taking strong inhibitors of CYP3A4 will be excluded from the study unless
             therapeutic substitution is possible

          -  Subjects taking strong inducers of CYP3A4 will be excluded from the study unless
             therapeutic substitution is possible

          -  Use of systemic immunosuppressive agents within 14 days prior to first dose of
             FF-10101

          -  Subjects taking drugs known to cause Torsades de Pointes will be excluded from the
             study unless therapeutic substitution is possible

          -  Subjects known to have long QT syndrome

          -  Subjects with mean QTcF values following 3 ECGs conducted 5 minutes apart of >470 msec