The purpose of this study is to determine whether Gemcitabine/Oxaliplatin (GEMOX) with or without Erlotinib (Tarceva) is effective in the treatment of unresectable, metastatic biliary tract carcinoma.

This is a phase III study of Gemcitabine/Oxaliplatin (GEMOX) with or without Erlotinib in unresectable, metastatic biliary tract carcinoma.

Inclusion Criteria:

1. age ≥ 18
2. histologically or cytologically confirmed adenocarcinoma of biliary tract
3. unresectable or metastatic
4. ECOG performance status of 0~2
5. measurable or evaluable lesion per RECIST criteria
6. adequate marrow, hepatic, renal and cardiac functions
7. no prior chemotherapy or molecularly targeted therapy for the advanced biliary carcinoma (prior adjuvant chemotherapy will be allowed if administered ≥ 6 months from the study entry)
8. provision of a signed written informed consent

Exclusion Criteria:

1. severe co-morbid illness and/or active infections
2. pregnant or lactating women
3. active CNS metastases not controllable with radiotherapy or corticosteroids
4. known history of hypersensitivity to study drugs
5. prior exposure to EGFR tyrosine kinase inhibitor