A real-world study of nab-paclitaxel-based chemotherapy with or without PD-1/PD-L1 blockade in second-line treatment of advanced biliary tract cancer.

e16242 Background: Nab-paclitaxel has shown promising antitumor activity in biliary tract cancer (BTC). Although gemcitabine-cisplatin combined with immune checkpoint inhibitors (ICIs) has become the standard treatment, many patients in clinical practice do not receive ICIs in the first-line setting. This study assessed the efficacy and safety of nab-paclitaxel-based chemotherapy, with or without ICI as second-line treatment for advanced BTC in a real-world setting. Methods: We included all consecutive BTC patients treated at West China Hospital between August 2018 and August 2023. Eligible patients had histologically confirmed locally advanced or metastatic BTC, had received first-line systemic therapy or adjuvant therapy with metastasis or recurrence occurring ≤6 months from the last dose, had received second-line nab-paclitaxel-based therapy, and had at least one radiographic response assessment. The primary endpoint was overall survival (OS). Secondary endpoints included progression-free survival (PFS), objective response rate (ORR), disease control rate (DCR), and adverse events (AEs). Results: A total of 84 patients received nab-paclitaxel-based chemotherapy (with ICI, n = 41; without ICI, n = 43). The median age was 57.5 years (IQR: 51.75–64.25), with 49% male. Primary tumor sites included intrahepatic cholangiocarcinoma (50%), extrahepatic cholangiocarcinoma (27.38%), and gallbladder cancer (22.62%). The mOS of the overall population was 15.17 months (95% CI, 12.63-21.43). No significant OS difference was observed between the nab-paclitaxel-based chemotherapy plus ICI group and the chemotherapy-only group (median OS: 16.90 vs. 14.60 months; HR: 0.74, 95% CI: 0.41–1.32, P = 0.30). Median PFS was 5.40 months (95% CI, 3.23–8.03) overall, 7.30 months (95% CI, 5.03–10.07) for nab-paclitaxel-based chemotherapy plus ICI, and 4.60 months (95% CI, 2.83–7.53) for nab-paclitaxel-based chemotherapy (HR: 0.66, 95% CI: 0.41–1.06, P = 0.09). The confirmed ORR was 29.27% in the nab-paclitaxel-based chemotherapy plus ICI group and 13.95% in the chemotherapy-only group (odds ratio, 2.56; 95% CI, 0.506–4.51). DCR was 68.29% in the nab-paclitaxel-based chemotherapy plus ICI group and 53.49% in the chemotherapy-only group (odds ratio, 2.56; 95% CI, 0.506–4.51). Common grade 3/4 adverse events in the overall population included leukopenia (21.43%), neutropenia (17.86%), and anemia (13.10%). Grade 3/4 immune-related adverse events (irAEs) included hepatitis (14.63%), colitis (2.44%), and pneumonia (2.44%). Conclusions: Nab-paclitaxel-based therapy showed manageable safety and promising efficacy for advanced BTC. No significant difference in survival was observed between nab-paclitaxel-based chemotherapy plus ICI and the chemotherapy-only group.