Inclusion Criteria:
1. Age 20 years or older, at the time of acquisition of informed consent
2. Histologically confirmed metastatic and/or advanced GIST with CD117(+), DOG-1(+), or mutation in KIT or PDGFRα gene
3. Failed (progressed and/or intolerable) after prior treatments for GIST, including at least imatinib and sunitinib, regorafenib.
4. Adequate tissue obtained after treatment failure to imatinib, sunitinib, and regorafenib for P-glycoprotein immunohistochemistry (IHC) analysis, and showed P-glycoprotein expression of less than 6. (For patients with PDGFRα D842V mutation or other subtypes with poor response to tyrosine kinase inhibitors, tumor tissue obtained at any period can be used.)
5. Eastern Cooperative Oncology Group (ECOG) performance status 0\~2
6. Resolution of all toxic effects of prior treatments to grade 0 or 1 by NCI-CTCAE version 5.0
7. At least one measurable lesion as defined by RECIST version 1.1.
8. Adequate bone marrow, hepatic, renal, and other organ functions
* Neutrophil \>1,500/mm3
* Platelet \> 100,000/mm3
* Hemoglobin \>8.0 g/dL
* Total bilirubin \< 1.5 x upper limit of normal (ULN)
* AST/ALT \< 2.5 x ULN
* Creatinine \<1.5 x ULN
9. Life expectancy \> 12 weeks
10. Washout period of previous TKIs or chemotherapy for more than 4 times the half life ((Imatinib and regorafenib need 1 week and sunitinib need 2 weeks.)
11. Provision of a signed written informed consent
Exclusion Criteria:
1. Women of child-bearing potential who are pregnant or breast feeding
2. Women or men who are not willing to use effective contraception entering the study period or until at least 3 months after the last study drug administration.
3. If any of the following applies within ≤ 6 months prior to starting study enrollment : Myocardial Infarction, severe instable angina, coronary/peripheral bypass, NYHA class III or IV congestive heart failure, stroke or transient ischemic attack, treatment required severe arrhythmia.
4. Uncontrolled infection
5. Diabetes mellitus with clinically significant peripheral artery disease
6. Acute and chronic liver disease and all chronic liver impairment.(But Patients with stable chronic hepatitis B are eligible)
7. Uncontrolled gastrointestinal toxicities with toxicity greater than NCI CTCAE grade 2
8. Acute, or chronic medical or psychiatric condition or laboratory abnormality such as active uncontrolled infection that difficult to study participation in the judgment of the investigator
9. The patient experienced any bleeding episode considered life-threatening, or any grade 3 or 4 bleeding event. (required transfusion or endoscopic or surgical intervention)
10. Patient who underwent major surgery or is under recovery from surgery within 28 days from the study treatment
11. Known diagnosis of HIV infection (HIV testing is not mandatory).
12. History of another primary malignancy that is currently clinically significant or currently requires active intervention.
13. Patients with clinically suspected brain metastasis symptom, brain metastases as assessed by radiologic imaging.
14. Alcohol or substance abuse disorder.
15. Known severe hypersensitivity to paclitaxel
16. Received paclitaxel-based treatment for GIST
