GemCis Plus PD-1/PD-L1 Inhibitor in Advanced Biliary Tract Cancer: Efficacy and Immune Microenvironment （BTC-IM-1）

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.

This is a prospective, non-interventional, observational study evaluating 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. The primary endpoint is objective response rate (ORR), with secondary endpoints including disease control rate (DCR), duration of response (DOR), time to response (TTR), progression-free survival (PFS), overall survival (OS), and immune profiling of tumor tissue and peripheral blood before and after treatment.

Inclusion Criteria:

• 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.

Exclusion Criteria:

• Prior systemic therapy.
• Active autoimmune disease requiring immunosuppression.
• Active infection requiring IV antibiotics.
• HIV-positive or active HBV/HCV infection (HBsAg+ with HBV DNA ≥2000 IU/mL; HCV RNA+).
• Symptomatic CNS metastases.
• Pregnancy/lactation.
• Any condition compromising protocol compliance or data interpretation per investigator.