Efficacy and safety of durvalumab and gemcitabine-based chemotherapy combined with or without lenvatinib in advanced biliary tract cancer.

595 Background: Immunotherapy in combination with gemcitabine-based chemotherapy, has now become the standard first-line treatment for advanced biliary tract cancer (BTC). Some small-sample studies have shown that immune checkpoint inhibitors (ICIs), when used in combination with lenvatinib and chemotherapy as first-line therapy, exhibit high anti-tumor activity in BTC. Therefore, we conducted a retrospective study to assess the efficacy and safety of durvalumab and gemcitabine-based chemotherapy with or without lenvatinib, in combination for advanced BTC in the real world. Methods: Between January 2021 and September 2024, patients with advanced BTC who received either durvalumab combined with or without lenvatinib, along with gemcitabine-based chemotherapy, were enrolled in this study. The study endpoints were overall survival (OS), progression-free survival (PFS), objective response rate (ORR), disease control rate (DCR), and safety. Results: Thirty patients with advanced BTC were included in this study. Fourteen (46.7%) patients had received durvalumab combined with lenvatinib plus chemotherapy. For all the patients, the median OS was 9.5 months(95% CI: 4.98-14.02), and the median PFS was 5.9 months(95% CI: 4.56-7.24). ORR was 43.4% and DCR was 76.7%. Patients with lenvatinib treatment had a longer median PFS (7.1 vs. 4.6 months, P = 0.06) compared with the non-lenvatinib treatment group. However, the median OS was shorter in patients with lenvatinib treatment group (9.0 vs. 9.5 months, P = 0.915). ORR and DCR in patients with lenvatinib were 57.1% and 92.9%, respectively. However, in patients without lenvatinib treatment group, ORR and DCR were only 31.2% and 62.5%, respectively. All patients experienced adverse events (AEs), addition of lenvatinib does not increase the risk of AEs. The data is still being updated. Conclusions: Durvalumab and gemcitabine-based chemotherapy combined with or without lenvatinib has shown to be effective and safe in routine practice. Regarding lenvatinib, its addition has only improved the DCR, ORR, and PFS, but has not been able to prolong OS.