Antibiotic therapy and association with oncological outcomes from targeted and immune-based therapy in hepatocellular carcinoma (HCC).

Abstract

4089 Background: Immune checkpoint inhibitors (ICI) alone or in combination with tyrosine kinase (TKI) or VEGF pathway inhibitors (VEGFi) are therapeutic options in unresectable HCC (uHCC). Whether exposure to antibiotics (ATB), a consolidated adverse prognostic factor in ICI recipients, affects outcome in HCC remains unclear. Methods: FDA analysed patient-level data of 4098 patients receiving ICI (n = 842) either as monotherapy (n = 258) or combinations (n = 584), TKI (N = 1968), VEGFi (n = 480) or placebo (n = 808) as part of 9 international clinical trials submitted to the US Food and Drug Administration in support of marketing applications. Associations for ATB exposure within 30 days before or after initiation of anti-cancer treatment (ATB) with overall (OS) and progression-free survival (PFS) were examined across therapeutic modality. Estimates were weighted by propensity score (PSW) using clinically relevant covariates. Results: Out of 4098 patients with uHCC mostly secondary to Hepatitis B (39%) or C (21%) infection, the majority were males (83%) with a median age of 64 (range 18-88), ECOG performance status of 0 (60%) and Child-Pugh A class (98%). Most patients had metastases (68%) but did not have macrovascular invasion (71%). Overall, 620 patients (15%) were ATB+, with comparable rates across placebo (12%), TKI (16%), VEGFi (15%), and ICI (16%). In the overall population, ATB was associated with shorter PFS (2.8 vs 3.9 months [m], HR 1.29, 95%CI 1.22-1.36) and OS (6.4 vs. 8.8 m; HR 1.36, 95%CI 1.29-1.43). In PSW analyses, ATB was associated with shorter PFS in patients treated with ICI (HR 1.52, 95%CI 1.34-1.73), TKI (HR 1.29, 95%CI 1.19-1.39) and placebo (HR 1.23, 95%CI 1.11-1.37). Similar results were observed in PSW analyses of OS in patients treated with ICI (HR 1.22, 95%CI 1.08-1.38), TKI HR 1.40, 95%CI 1.30-1.52), and placebo (HR 1.40, 95%CI 1.25-1.57). Consistent outcomes were observed for ATB+ patients within ICI treatment subgroups, including patients treated with anti-PD-1 monotherapy (PFS HR 1.49, 95%CI 1.22-1.80; OS HR 1.31 1.02-1.68) and ICI combinations (PFS HR 1.50, 95%CI 1.26-1.77; OS HR 1.14 0.99-1.32). Conclusions: Unlike other oncological indications where the detrimental effect of ATB may be more prominent in ICI recipients, ATB is associated with inferior outcomes across a broad range of anti-cancer therapies for HCC and placebo. Whether ATB is causally linked to worse outcomes through disruption of the gut liver axis remains to be demonstrated in translational studies.