Integrative clinical and molecular analysis of advanced biliary tract cancers on immune checkpoint blockade reveals potential markers of response

Background While there have been encouraging preliminary clinical results for immune checkpoint inhibitors (ICIs) in BTCs, it remains a challenge to identify the subset of patients who may benefit. In this study, we evaluated the efficacy of ICI treatment in patients with advanced BTCs, and explored potential biomarkers that are predictive of response. Methods The study enrolled 26 patients with advanced microsatellite stable BTCs (15 with gallbladder cancers [GCs] and 11 with intrahepatic cholangiocarcinoma [ICCs]) who received ICI treatment. Targeted next‐generation sequencing (NGS) was performed on tumor tissue samples collected from 17 patients. Clinical and genomic characteristics were assessed for the correlation with clinical outcome. Results Analysis of the baseline clinical characteristics showed that performance score (PS) of 0 was associated with a better prognosis than PS of 1 (HR = 1.08 × 109; 95% CI, 0∼Inf; P = .002). No significant correlations were found between clinical outcome and inflammation‐related indicators. NGS profiling of the available tumor tissues, revealed largely non‐overlapping somatic alterations between GCs and ICCs. Mutations in LRP1B (HR = 0.26; 95% CI, 0.06‐1.21; P = .067), ERBB2 (HR = 0.15; 95% CI, 0.02‐1.19; P = .04), or PKHD1 (HR