Comparison of efficacy and safety of PD-1 and PD-L1 antibodies in combination with hepatic arterial infusion chemotherapy and target therapy for unresectable intrahepatic cholangiocarcinoma: A multicenter retrospective study.

553 Background: Immune checkpoint inhibitors (ICIs) in combination with hepatic arterial infusion chemotherapy (HAIC) and target therapy have shown promising antitumor activity in unresectable intrahepatic cholangiocarcinoma (iCCA). The present study aimed to compare the efficacy and safety of programmed cell death protein 1 (PD-1) inhibitors and programmed cell death ligand 1 (PD-L1) inhibitors in this setting. Methods: In this multicenter retrospective study, we included patients with iCCA who received ICIs + HAIC + target therapy from June 2018 to June 2023. Propensity score matching (PSM) was performed to reduce confounding factors. Patients were divided into two groups: those treated with PD-L1 antibody + HAIC + target therapy (Group A) and those treated with PD-1 antibody + HAIC + target therapy (Group B). Progression-free survival (PFS), overall survival (OS), and objective response rate (ORR) were compared between the two groups. Adverse events were assessed according to CTCAE v5.0. Results: A total of 336 patients met the inclusion criteria and were enrolled for analysis. There were no significant differences in OS, PFS, or ORR between the two groups (median OS: 17.7 vs. 25.3 months, P=0.139; median PFS: 8.3 vs. 10.0 months, P=0.534; ORR: 48.4% vs. 31.1%, P=0.051). Following PSM (ratio = 3, caliper = 0.2), 30 patients in Group A and 83 patients in Group B were included. The ORR, according to the modified RECIST criteria, was significantly higher in Group A compared to Group B (50% vs. 28.9%, P=0.037). However, no significant difference in PFS (median 10.0 vs. 9.0 months, P=0.29) or OS (median 17.6 vs. 22.8 months, P=0.293) was observed between the two groups. Adverse events (AEs) occurred in all 113 patients (100%), wherein grade 3–4 AEs were reported for 12 (10.6%) patients in group A and 45 (39.8%) in group B. There was a tendency for Group A to have a lower incidence of grade 3–4 AEs compared to Group B (40.0% vs. 54.2%, P=0.182),although this difference was not statistically significant. Conclusions: This study found that in the treatment combining ICIs with HAIC and target therapy for unresectable iCCA, Group A demonstrated a superior tumor response and a more favorable safety profile.