Real-world outcomes of chemoimmunotherapy in advanced biliary tract cancer: a multicenter study with a propensity-matched historical cohort

Background Biliary tract cancer (BTC) comprises a heterogeneous group of malignancies, often diagnosed at advanced stages. Phase III trials have shown that adding immune checkpoint inhibitors (ICIs) to gemcitabine and cisplatin improves survival, supporting their use as first-line therapy; however, real-world evidence remains limited. Materials and methods We conducted a multicenter observational study including patients with advanced BTC treated with ICI-based regimens plus chemotherapy. Clinical data were retrospectively collected. Overall survival (OS) was estimated using the Kaplan–Meier method, and prognostic factors were evaluated with multivariate Cox regression. A historical control cohort without ICI exposure was analyzed using propensity score matching. Results A total of 152 patients received ICI-based therapy (median age 66.5 years, 57.9% men, and 68.4% metastatic). The most common primary sites were intrahepatic cholangiocarcinoma (52.6%) and gallbladder carcinoma (23.7%). Durvalumab plus gemcitabine/cisplatin was used in 88.1% of cases. After a median follow-up of 8.3 months, the median OS was 15.5 months (95% confidence interval 12.3-21.5), and the response rate was 38.8%. Maintenance therapy was given to 37.5%, mainly as ICI monotherapy. Independent adverse prognostic factors included Eastern Cooperative Oncology Group performance status of >0 [hazard ratio (HR) 3.91], neutrophil-to-lymphocyte ratio of ≥3 (HR 1.98), and vascular invasion (HR 1.83). Ten (6.6%) grade ≥2 immune-related adverse events were reported. A propensity score-matched analysis showed improved survival with ICI versus the historical cohort without ICI (HR 0.61, P = 0.025). Conclusion In this real-world cohort, ICI plus chemotherapy achieved outcomes comparable with pivotal trials, supporting its effectiveness in broader populations and highlighting the need for improved access.