- Histologically-proven diagnosis of malignant GIST (Gastrointestinal Stromal Tumors).
- Evidence of unidimensionally measurable disease
- Failure of prior treatment with imatinib or intolerant to imatinib
- Male or female, 18 years of age or older.
- ECOG (Eastern Cooperative Oncology Group) performance status 0 or 1.
- Resolution of all acute toxic effects
- Adequate organ function.
- Anticancer treatment after last dose of imatinib
- Major surgery within 4 weeks or radiation therapy within 2 weeks.
- Grade 3 hemorrhage within 4 weeks prior to starting the study treatment.
- Diagnosis of second malignancy within the last 5 years.
- History of brain disease.
- Cardiac disease within 12 months.
- Thyroid function abnormality.
- Ongoing cardiac dysrhythmias.
- Uncontrolled hypertension.
- Ongoing treatment with anticoagulant and CYP3A4 inhibitors and inducers.
- HIV or AIDS related illness.
- Pregnancy or breastfeeding.