Regorafenib in Patients With Metastatic and/or Unresectable Gastrointestinal Stromal Tumor

- In this research study, each planned "cycle" of the study lasts 4 weeks. In the first
cycle, participants will come to the clinic on Days 1, 15 and 16. For cycles 2 through
4, they will come to the clinic on Days 1 and 15 of each cycle. For cycle 5 and beyond,
they will come to the clinic on Day 1 of each cycle. Repeat tumor imaging will be
performed at the end of every 2 cycles during study drug administration (e.g. end of
cycles 2, 4, 6, etc.)

- During each cycle, participants will take regorafenib by mouth, once a day in the
morning, for 3 weeks followed by one week during which you do not take regorafenib (the
"rest period").

- FDG-PET/CT (Positron Emission Tomography) scans are required as part of this study to
monitor effects of the study drug on the participant's GIST. The first scan will take
place before the first dose of study drug. If the first scan shows that the "tracer
sugar" collection is increased in the participant's GIST, they will have up to 5
additional scans performed at different time points throughout their participation in
this research study.

- Participants may continue to participate in this research study for as long as they do
not have serious side effects or their disease does not get worse.

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