• 18 years of age or older

• Histologically or cytologically confirmed unresectable advanced, metastatic, or recurrent biliary tract cancers (including intrahepatic cholangiocarcinoma, extrahepatic cholangiocarcinoma, gallbladder cancer, and ampullary carcinoma)

• Patients must have radiologically documented progression after a prior gemcitabine and platinum containing chemotherapy regimen as first line therapy for locally advanced unresectable or metastatic disease.

∙ Patients who received perioperative treatment (adjuvant and neoadjuvant) may be eligible, as determined by the Sponsor Medical Monitor.

‣ Patients whose first line regimen was modified due to toxicity before disease progression, may be eligible, as determined by the Sponsor Medical Monitor.

• At least one lesion measurable as defined by RECIST v1.1

• Eastern Cooperative Oncology Group (ECOG) Performance Status 0-1

• Predicted life expectancy of at least 12 weeks

• No evidence of ongoing infection and adequate biliary excretion or patients whose adequate biliary excretion can be confirmed with the following procedures:

∙ Patients who underwent endoscopic retrograde biliary drainage (ERBD) at least 1 week before the investigational drug treatment

‣ Patients with endobiliary stents are eligible, provided there is no evidence of obstruction

‣ Patients free of any signs of active or suspected uncontrolled infection after a drainage procedure

‣ Patients free of any risk of hemorrhage and with incision completely healed

• Adequate bone marrow, hepatic, and renal function within 14 days of randomization as described below. (Patient must be free of G-CSF treatment and blood transfusion within 14 days prior to the lab test):

∙ Absolute neutrophil count (ANC) ≥ 1,500/mm3

‣ Hemoglobin ≥ 9.0 g/dL

‣ Platelet count ≥ 100,000/mm3

‣ Total bilirubin ≤ 1.5 X ULN

‣ AST/ALT ≤ 3.0 X ULN (≤5 X ULN in case of hepatic metastasis)

‣ Estimated creatinine clearance ≥ 30 mL/min based on Cockcroft-Gault

‣ Urine protein ≤ 1+ by Dipstick (Only when urinalysis shows a protein dipstick result of \> 1 positive (+), the total protein volume (\<1.0 g/24hr) can be confirmed with a 24-hour urine test.)

‣ Serum amylase and lipase level ≤ 3X ULN

‣ Serum Albumin ≥ 3.0 g/dL

• Female patients who are women of childbearing potential (WCBP) must have a negative pregnancy test (serum-hCG or urine-hCG performed at the Investigator's discretion) within 14 days of randomization

⁃ Female patients must be surgically sterile (or have a monogamous partner who is surgically sterile) or be at least 2 years postmenopausal or commit to use 2 acceptable forms of birth control (defined as the use of an intrauterine device (IUD), a barrier method with spermicide, condoms, or any form of hormonal contraceptives) or abstinence for the duration of the study and for 6 months following the last dose of study treatment. Male patients must be sterile (biologically or surgically) or commit to the use of a reliable method of birth control (condoms with spermicide) for the duration of the study and for 6 months following the last dose of study treatment.

⁃ Signed and dated Institutional Review Board (IRB)/Independent Ethics Committee (IEC) approved Informed Consent Form (ICF) before any protocol-directed screening procedures are performed