Aim: This retrospective study aimed to investigate the impact of proton pump inhibitor treatment (PPI) and antibiotic treatment on the therapeutic outcomes of hepatocellular carcinoma (HCC) patients receiving atezolizumab and bevacizumab (Atez/Bev).
Methods: The present study included a total of 441 HCC patients who were treated with Atez/Bev in 20 Japanese institutions from September 2020 to April 2022. We adopted the inverse probability of treatment weight to adjust for imbalance in the baseline characteristics of patients with and without PPI treatment as well as patients with and without antibiotic treatment.
Results: The progression-free survival (PFS) and overall survival (OS) of patients with and without PPI treatment did not differ to a statistically significant extent. In the weighted cohort, the difference in PFS and OS between the patients with and without PPI did not reach statistical significance (median PFS, 7.0 vs. 6.5 months, p = 0.07; 1-year survival rate 66.3% and 73.8%, p = 0.9). The PFS and OS in patients with antibiotic treatment were worse in comparison to patients without antibiotic treatment (median PFS, 3.8 vs. 7.0 months, p = 0.007; 1-year survival rate 58.8% and 70.3%, p = 0.01). In the weighted cohort, the PFS and OS of the two groups did not differ to a statistically significant extent (median PFS, 3.8 vs. 6.7 months, p = 0.2; 1-year survival rate, 61.8% and 71.0%, p = 0.6).
Conclusions: The therapeutic outcomes of Atez/Bev in HCC patients did not differ between patients with and without PPI treatment or between patients with and without antibiotic treatment.
Keywords: antibiotic; atezolizumab; bevacizumab; gut microbiome; hepatocellular carcinoma; immune checkpoint inhibitor; proton pump inhibitor.
© 2023 Japan Society of Hepatology.