Biliary disorders associated with immune checkpoint inhibitors: a pharmacovigilance analysis of the FDA adverse event reporting system (FAERS) database

Immune checkpoint inhibitors (ICIs) are linked to severe biliary disorders (BDs). Using FAERS data (Q1 2015-Q1 2025), we identified 4,405 BD cases via standardized MedDRA queries (144 preferred terms). ICIs were significantly associated with BDs (overall ROR 3.37, 95% CI 3.28-3.47). Anti‑PD‑1/PD‑L1 monotherapy showed higher risk than anti‑CTLA‑4 (ROR 3.19-4.19 vs 2.57), while combination therapy displayed extreme risks for bile duct necrosis (ROR 530.58) and immune‑mediated cholangitis (ROR 550.54). Fatal outcomes occurred in 19.9% (N=875) and were more common in males, patients aged >65 years, and those weighing <50 kg. Median time‑to‑onset was shortest for anti‑CTLA‑4 (44.8 days, IQR 14-65); fatal cases had earlier onset than nonfatal ones (67.6 vs 114.3 days, P<0.0001). These findings highlight the strong association between ICI therapy and severe biliary injury, supporting the need for early biliary monitoring, particularly in high‑risk patients.