A Study on the Association Between Treatment Response to Atezolizumab Plus Bevacizumab Combination Therapy for Advanced Hepatocellular Carcinoma and Gut Microbiota

Recent findings suggest that the gut microbiota modulates antitumor immunity and influences the efficacy of immune checkpoint inhibitors, yet no established consensus has been reached. This study examined the association between gut microbiota composition before initiation of atezolizumab plus bevacizumab combination therapy (Atez/Bev) and treatment response in patients with advanced hepatocellular carcinoma (HCC). Twenty-nine patients with advanced HCC from whom stool samples were collected before Atez/Bev treatment were enrolled. A comparative analysis was performed between the responder and non-responder groups to identify the genera associated with treatment response and progression-free survival (PFS). A total of 90 genera were identified. ROC analysis was performed for the responder and non-responder groups using the relative abundance of each genus. The prevalence of Faecalibacterium was significantly correlated with the responder group. Furthermore, multivariate analysis incorporating clinical prognostic factors also showed a statistically significant correlation between the prevalence of Faecalibacterium and the responder group. Analysis of the association with PFS revealed significantly prolonged PFS in the Acidaminococcus-high, Megamonas-high, Lachnoclostridium-low, and Flavonifractor-low groups. Multivariate analysis for PFS also confirmed significant correlations with the prevalence of Acidaminococcus and Megamonas. Our results suggest that gut microbiota may be associated with the efficacy of Atez/Bev treatment for advanced HCC.