|Inclusion Criteria:||1) Phase I criteria|
2) Patients must have pathologically-confirmed acute leukemia, refractory or relapsed after standard therapy for the disease or for which conventional systemic chemotherapy is not reliably effective or no effective therapy is available.
3) Aged >/= 18 years.
4) ECOG Performance Status of 0, 1 or 2.
5) Adequate clinical laboratory values (i.e., plasma creatinine </= 1.5 x upper limit of normal (ULN) for the institution, bilirubin </= 1.5 x ULN, alanine transaminase (ALT) and aspartate transaminase (AST) </= 2.5 x ULN).
6) Absence of CNS involvement by leukemia.
7) Absence of uncontrolled intercurrent illnesses, including uncontrolled infections, cardiac conditions, or other organ dysfunctions.
8) Signed informed consent prior to the start of any study specific procedures.
9) Women of child-bearing potential must have a negative serum or urine pregnancy test. Male and female patients must agree to use acceptable contraceptive methods for the duration of the study and for at least one month after the last drug administration.
10) Phase II Criteria
11) Same criteria as phase I, with the following exceptions to #1: Histologically or pathologically confirmed diagnosis of AML based on WHO classification that is refractory after standard therapy, or for which conventional systemic chemotherapy is not reliably effective, or no effective therapy is available. Patients aged 60 years or older with newly diagnosed AML who are not eligible for, or who refuse, standard care are also eligible.