This study of AMG 900 will be conducted in two parts: dose escalation and dose expansion. The dose escalation part of the study is aimed at evaluating the safety, tolerability and PK (pharmacokinetics) of oral AMG 900 in subjects with acute myeloid leukemia. Up to 93 subjects may be enrolled in dose escalation. The dose expansion part of the study will consist of 20 subjects with acute myeloid leukemia. The dose of AMG 900 will be dependent upon data from the dose escalation part of the study.

Inclusion Criteria:

• Men or women ≥ 18 years old
• Pathologically documented, definitively diagnosed AML that has failed standard treatments or for which no standard therapy is available or the subject refuses standard therapy
• Must consent to undergo bone marrow biopsies per schedule of assessments

Exclusion Criteria:

• White blood cell greater than 20,000 uL
• History of or active central nervous system leukemia
• Prior allogeneic bone marrow transplant
• Subject will not be available for protocol-required study visits or procedures

Other Inclusion/ Exclusion Criteria may apply to qualify for enrollment