A Prospective, Non-interventional Study of Gemcitabine/Cisplatin Combined With PD-1/PD-L1 Inhibitor as First-line Treatment in Treatment-naïve Advanced Biliary Tract Cancer Patients: Efficacy and Immune Microenvironment Dynamics
To evaluate the efficacy and immune microenvironment changes in treatment-naïve advanced biliary tract cancer (BTC) patients receiving first-line standard therapy with gemcitabine/cisplatin (GemCis) combined with PD-1/PD-L1 inhibitors.
• Age ≥18 years.
• Histologically confirmed unresectable/metastatic cholangiocarcinoma (intrahepatic, extrahepatic, or gallbladder).
• No prior systemic anticancer therapy (chemotherapy, targeted therapy, or immunotherapy).
• Planned to receive GemCis+PD-1/PD-L1 inhibitor as standard first-line treatment.
• ≥1 measurable lesion per RECIST 1.1.
• ECOG performance status 0-1.
• Adequate organ function:
‣ ANC ≥1.5 × 10⁹/L, platelets ≥100 × 10⁹/L, hemoglobin ≥9 g/dL.
⁃ Total bilirubin ≤1.5 × ULN, AST/ALT ≤3 × ULN (≤5 × ULN if liver metastases).
⁃ Creatinine ≤1.5 × ULN or CrCl ≥60 mL/min.
• Willing to provide archival/fresh tumor tissue and peripheral blood samples.
• Signed informed consent.