Inclusion Criteria

Inclusion criteria:

- Adult subjects, 18 years or older

- Adequate liver and kidney function

- Prior history of ≥grade 2 thrombocytopenia (platelet nadir ≤ 75,000/microliters)

- Ability to ingest and retain oral medication

- Practice acceptable birth control

- Ability to understand and follow study requirements

- Life expectancy of at least 3 months

Exclusion criteria:

- History of platelet disorders, dysfunction, or a bleeding disorder

- Anti-coagulant used within 2 weeks prior to study start

- Females who are lactating or expecting

- History of thromboembolic events or drug induced thrombocytopenia

- History of central nervous system, brain and/or leptomeningeal metastases

- Prior surgery within 2 weeks or radiotherapy within 4 weeks of study start

- Pre-existing cardiac disease