• Pathologically confirmed G1 or G2 NET of GEP origin with locally advanced or metastatic stage who failed to one line or more than one line of small molecular kinase inhibitor (mTOR inhibitor or other targeted kinase inhibitor) or W-D G3 NET of GEP origin with locally advanced or metastatic stage who failed to one line or more than one line of chemotherapy or small molecule kinase inhibitor.

• Radiologic progression within 12 months of entry

• Recovery to baseline or ≤ Grade 1 CTCAE v5 from toxicities related to any prior treatments, unless AE(s) are clinically non-significant and/or stable on supportive therapy.

• Age≥ 20 years old and ECOG Performance Status ≤ 1.

• Adequate organ and marrow function, based upon meeting all the following laboratory criteria within 14 days before first dose of study treatment:

∙ Absolute neutrophil count (ANC) ≥ 1500/µL without granulocyte colony- stimulating factor support.

‣ White blood cell count ≥ 2500/µL.

‣ Platelets ≥ 100,000/µL without transfusion.

‣ Hemoglobin ≥ 9 g/dL (≥ 90 g/L).

‣ Alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP) ≤ 3 x upper limit of normal (ULN). If there is liver metastasis, AST, ALT ≤ 5 x ULN. ALP ≤ 5 x ULN with documented bone metastases.

‣ Total bilirubin ≤ 1.5 x ULN (for subjects with Gilbert's disease ≤ 3 x ULN).

‣ Serum albumin ≥ 2.8 g/dl

‣ (PT)/INR or partial thromboplastin time (PTT) test \< 1.3 x the laboratory ULN

‣ Serum creatinine ≤ 1.5 x ULN or calculated creatinine clearance ≥ 50 mL/min (≥ 0.5 mL/sec) using the Cockcroft-Gault equation:

∙ Males: (140 - age) x weight (kg)/(serum creatinine \[mg/dL\] × 72) Females: \[(140 - age) x weight (kg)/(serum creatinine \[mg/dL\] ×72)\] × 0.85

∙ Urine protein/creatinine ratio (UPCR) ≤ 1 mg/mg (≤ 113.2 mg/mmol), or 24-h urine protein ≤ 1 g

• At least one measurable lesion according to RECIST 1.1 over non-locally treated site, such as RT, TAE (TACE), or RFA.

• Life expectancy greater than 12 weeks.

• Capable of understanding and complying with the protocol requirements and must have signed informed consent document.

• Female subjects of childbearing potential (i.e. less than or equal to 2 years post-menopause and not surgically sterile) and their partners must agree to use highly effective methods of contraception (that alone or in combination result in a failure rate of less than 1% per year when used consistently and correctly during the course of the study and for 4 months after the last dose of study treatment.

• \* Effective methods of birth control include:

⁃ Hormonal contraception (oral, injectable, implantable, transdermal) plus a barrier method;

⁃ intrauterine device (IUD) or intrauterine hormone-releasing system (IUS) plus a barrier method;

⁃ bilateral tubal occlusion (females);

⁃ vasectomized partner (males).

⁃ Female subjects of childbearing potential must not be pregnant at screening. Female subjects are considered to be of childbearing potential unless one of the following criteria are met: documented permanent sterilization (hysterectomy, bilateral salpingectomy, or bilateral oophorectomy) or documented postmenopausal status (defined as 12 months of amenorrhea in a woman \> 45 years-of-age in the absence of other biological or physiological causes. In addition, females \< 55 years-of-age must have a serum follicle stimulating (FSH) level \> 40 mIU/mL to confirm menopause). Note: Documentation may include review of medical records, medical examinations, or medical history interview by study site.