Inclusion Criteria:

- At least 18 years of age at the time of study entry

- Histologically confirmed metastatic and/or unresectable GIST with prior failure of
both conventional tyrosine kinase inhibitors, imatinib and sunitinib.

- Measurable disease per RECIST 1.1. A lesion in a previously irradiated area is
eligible to be considered as measurable disease as long as there is objective
evidence of progression of the lesion.

- ECOG Performance Status 0 or 1

- Adequate organ and marrow function as outlined in the protocol

- Fully recovered from the acute effects of prior cancer therapy before initiation of
study drug

- Patients must be suitable for oral drug administration

- Willingness to use effective means of birth control throughout the duration of
clinical study and for at least 3 months after completion of study drug

- Women of childbearing potential must have a negative pregnancy test performed within
7 days of the start of study drug administration

Exclusion Criteria:

- Use of any unapproved tyrosine kinase inhibitors or investigational agents within 2
weeks or 6 half-lives of the agent, whichever is shorter, prior to receiving study
drug

- Participants who have had radiotherapy within 4 weeks prior to study entry

- Major surgery, or significant traumatic injury within 4 weeks prior to study entry

- Presence of symptomatic or uncontrolled brain or central nervous system metastases

- Prior exposure to sorafenib

- Prior exposure to regorafenib

- Known or suspected allergy to the investigational agent or any agent given in
association with this trial

- Individuals with a history of a different malignancy, other than cervical cancer in
situ, basal cell or squamous cell carcinoma of the skin, are ineligible, except if
they have been disease-free for at least 5 years, and are deemed by the investigator
to be at low risk for recurrence of that malignancy or other primary malignancy is
neither currently clinically significant nor requiring active intervention

- Clinically significant cardiac arrhythmias and/or patients who require
anti-arrhythmic therapy (excluding beta blockers or digoxin)

- History of clinically significant cardiac disease or congestive heart failure > NYHA
class 2. Patients must not have unstable angina or new-onset angina within the last
3 months or myocardial infarction within the past 6 months

- Hypertension as defined by systolic blood pressure 140-159 mmHg or diastolic blood
pressure 90-99 mmHg; recurrent or persistent or symptomatic increase by > 20 mmHg
(diastolic) or to systolic blood pressure greater than 140 mmHg or diastolic blood
pressure greater than 90 mmHg if previously within normal limits, despite optimal
medical management

- Arterial or venous thrombotic or embolic events such as cerebrovascular accident
(including transient ischemic attacks), deep vein thrombosis or pulmonary embolism
within the 6 months before start of study medication

- Ongoing infection of Grade 3 or higher

- Patients with evidence of, or history of, bleeding diathesis. Any major hemorrhage
or bleeding event of Grade 3 or higher within 4 weeks of start of study medication

- Non-healing wound, ulcer or bone fracture

- Renal failure requiring hemo-or peritoneal dialysis

- Dehydration of Grade 2 or greater

- Persistent proteinuria Grade 3 or higher

- Known history of HIV infection or chronic hepatitis B or C

- Uncontrolled intercurrent illness

- Pregnant or lactating females