Clinical and economic outcomes of adding durvalumab to gemcitabine/cisplatin in advanced biliary tract cancers: A multicenter descriptive study.

[BACKGROUND] Durvalumab in combination with gemcitabine/cisplatin (GemCis) has expanded therapeutic options for advanced biliary tract cancers (BTCs), raising both clinical and economic considerations. We aim to describe the efficacy, safety and economic impact of durvalumab addition.

[METHODS] This retrospective study analyzed cohorts of patients receiving GemCis ± durvalumab. Progression-Free Survival (PFS) and Overall Survival (OS) were estimated using the Kaplan-Meier method. The economic impact of different dosing strategies was explored through scenario-based analyses.

[RESULTS] Median PFS was 7.4 months (95 %CI: 5.4-10.8) in the GemCis-durvalumab group and 6.1 months (95 %CI: 4.0-7.1) in the GemCis group. Median OS was 10.0 months (95 %CI: 5.9-12.8) and 9.7 months (95 %CI: 6.5-12.8), respectively. No severe immune related adverse events were reported. The median treatment cost per patient was €36,342 for GemCis-Durvalumab versus €173 for GemCis alone. Economic analysis suggested that adjusting durvalumab dosing (20mg/kg instead of a flat dose) could lead to saved costs of €344 to €2547 per infusion without affecting outcomes.

[CONCLUSIONS] This study confirms effectiveness of durvalumab, aligning with clinical trial results. However, the substantial economic burden underscores the importance of optimizing dosing strategies. The recent approval of pembrolizumab further highlights the need for prospective cost-benefit comparisons studies incorporating predictive biomarkers.