The trial will recruit 43 patients. At the first step, 10 patients will be recruited. Only when at least 4 patients achieve objective response will the trial enter the second step and continue to recruit other patients. After being enrolled, all patients giving written informed consent will receive treatment until progression of disease, unacceptable toxicity or death. The tumor response evaluation will be conducted on a regular basis until progression of disease. Long-term survival follow up will be conducted as well.
This is a phase 2, single-arm, open label study. The purpose is to investigate both the efficacy and safety of Envofolimab and Lenvatinib in combination with Gemcitabine plus Cisplatin for treatment of advanced biliary tract cancer as first-line treatment.