Inclusion Criteria:  Male or female patients aged 18 years or older at screening (aged 20 years or older in Taiwan) Histopathological or cytologic diagnosis of unresectable metastatic or locally advanced BTC (cholangiocarcinoma or gallbladder cancer) Subject must have failed from first line gemcitabine and cisplatin-based therapy with clear evidence of disease progression Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) of 0-1 Life expectancy is >12 weeks  Adequate bone marrow function, demonstrated by:  Absolute neutrophil count (ANC) ≥1,500 cell/mm3 Platelet count ≥ 100,000 cells/mm3 Hemoglobin ≥ 9 g/dL  Adequate liver function, demonstrated by:  Aspartate transaminase (AST) and alanine transaminase (ALT) ≤2.5 x upper limit of normal (ULN), or ≤5.0 x ULN in the case of liver metastases Total bilirubin ≤1.5 x ULN Albumin ≥3.0 g/dL International normalized ratio (INR) <1.5  Adequate renal function, demonstrated by:  Serum creatinine ≤1.5 x ULN Creatinine clearance ≥ 60mL/min calculated by Cockcroft-Gault formula or directly measured with 24hr urine collection A negative serum pregnancy test at screening and is not breastfeeding in woman of childbearing potential Women of childbearing potential or male subjects must use a medically acceptable form of contraception as 2 barrier methods (e.g., combination of condom, diaphragm, or intrauterine device), hormonal contraception (estrogen or progesterone agents) or 1 barrier method in combination with spermicide. Birth control is required 1 month prior to screening, for the duration of their study participation, and for 1 month after the end of the study; female partners of male subjects must adhere to the same birth control methods. Provision of a signed and dated written Informed Consent Form (ICF) prior to any study specific procedures Subject is willing to comply with protocol-required visit schedule and visit requirements No more than 60 days have elapsed between completion of the prior line of chemotherapy or CCRT and enrollment Subject has not received intervening systemic therapy since first-line treatment  Exclusion Criteria:  More than one prior chemotherapy regimen or any systemic therapy (chemotherapy, biologics, immunotherapy, or investigational agents) other than first line gemcitabine and cisplatin-based therapy for unresectable metastatic or locally advanced BTC Note: prior radiation (with or without radiosensitizing doses of chemotherapy) or fluoropyrimidine chemotherapy are allowed as postsurgical adjuvant therapy. Diagnosis of active malignancy other than BTC within the past 2 years, except nonmelanoma skin carcinoma and carcinoma-in-situ of uterine cervix treated with curative intent Prior discontinuation of gemcitabine because of pulmonary or hepatic toxicity or hemolytic uremic syndrome (HUS) or hypersensitivity, allergic reaction, or intolerance Known or suspected hypersensitivity to capecitabine, tegafur, gimeracil, oteracil potassium, oxaliplatin or other platinum compounds, leucovorin products, folic acid or folinic acid, 5-fluorouracil or their excipients. Prior discontinuation of fluoropyrimidine because of any unexpected or severe reaction. Treatment with brivudine, sorivudine, or its chemically-related analogs ≤ 28 days prior to the date of enrollment. Under flucytosine treatment. Residual toxicity from prior chemotherapy or CCRT that is Grade ≥2 (residual Grade 2 neuropathy and alopecia are permitted) Any GI disorder which would significantly impede absorption of an oral agent Known brain or leptomeningeal metastases Surgery or radiation therapy within the past 28 days Any active disease or condition that would not permit compliance with the protocol Clinically significant cardiovascular disease (e.g., uncontrolled hypertension, unstable angina, congestive heart failure, or New York Heart Association [NYHA] Grade 2 or greater), or uncontrolled serious cardiac arrhythmia Have documented cerebrovascular disease Have a seizure disorder not controlled on medication (based on decision of Investigator) Received an investigational agent within 28 days of enrollment Have an uncontrolled active viral, bacterial, or systemic fungal infection Known human immunodeficiency virus (HIV) infection Have hepatitis B virus (HBV) and/or hepatitis C virus (HCV) infection in medical history. If positive results are not indicative of true active or chronic infection, the subject can enter the study after discussion and agreement between the Investigator and the Clinical Research Organization (CRO) Medical Monitor Received yellow fever vaccine or other live attenuated vaccine(s) within the 4 weeks prior to screening History of drug or alcohol abuse within last year Have any other serious medical condition that, in the Investigator's medical opinion, would preclude safe participation in, and compliance with, a clinical trial