• Patients with functional or non-functional, well-differentiated, locally advanced unresectable or metastatic NETs of the GI tract, lung, or pancreas who have received 2 or less prior lines of therapy excluding somatostatin analogs

• Patients with functional NETs may enroll if:

∙ the patient has been on a stable dose of an somatostatin analogs for ≥12 weeks and

‣ the patient has experienced disease progression while on stable somatostatin analogs dose

• Patients must have 1 or more measurable target lesions by RECIST v1.1

• Age: 18 years or older

• Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1 or Karnofsky Performance Status (KPS) ≥80

• Adequate liver function:

∙ Total bilirubin ≤1.5 × upper limit of normal (ULN) (unless due to Gilbert's syndrome or attributable to liver metastases, then ≤3 × ULN)

‣ Aspartate aminotransferase (AST) and alanine transaminase (ALT) ≤2.5 × ULN (≤5 × ULN if attributable to liver metastases)

• Adequate renal function: creatinine clearance ≥30 mL/min, Cockcroft-Gault creatinine clearance = ((140-age) × weight\[kg\]) / (72 × serum creatinine \[mL/min\]) × 0.85, if female.

• Adequate hematologic parameters:

∙ Absolute neutrophil count (ANC) ≥1.0 × 10\^9/L (growth factor support allowed)

‣ Platelet count ≥100,000/mm\^3 (100 × 10\^9/L) (transfusion and/or growth factor support allowed)

‣ Hemoglobin ≥8.0 g/dL (transfusion and/or growth factor support allowed)

• Fasting serum triglyceride must be ≤300 mg/dL; fasting serum cholesterol must be less than or equal to 350 mg/dL

⁃ Minimum of 4 weeks since any major surgery, completion of radiation, and adequately recovered from the acute toxicities of any prior therapy, including neuropathy, to Grade ≤1

⁃ Male or non-pregnant and non-breastfeeding female:

• Females of childbearing potential must agree to use effective contraception or abstinence without interruption from 28 days prior to starting study medication throughout 3 months after last dose of study medication and have a negative serum pregnancy test (beta human chorionic gonadotropin \[β-hCG\]) result at screening and agree to ongoing pregnancy testing during the course of the study, and after the EOS treatment. A second form of birth control is required even if she has had a tubal ligation.

∙ Male patients must agree not to donate sperm and must practice abstinence or agree to use a condom during sexual contact with a pregnant female or a female of childbearing potential while participating in the study and throughout 3 months after last dose of study medication. A second form of birth control is required even if he has undergone a successful vasectomy.

∙ Sexual abstinence is considered a highly effective contraceptive method only if defined as refraining from heterosexual intercourse from 28 days prior to starting study medication throughout 3 months after last dose of study medication. The reliability of sexual abstinence should be evaluated in relation to the duration of the study and the preferred and usual lifestyle of the patient.

⁃ The patient or the patient's legal guardian(s) understand(s) and sign(s) the informed consent

⁃ Willingness and ability to comply with scheduled visits, laboratory tests, and other study procedures

⁃ Patients with a known history of human immunodeficiency virus (HIV) infection are eligible if:

• There has been no acquired immunodeficiency syndrome (AIDS)-defining opportunistic infection in 12 months prior to enrollment.

∙ The patient has been receiving an antiretroviral therapy regimen for ≥4 weeks and the HIV viral load is \<400 copies/mL prior to enrollment.

∙ Antiretroviral therapy regimen does not include strong cytochrome (CYP)3A4 inhibitors or inducers