Therapeutic efficacy of atezolizumab plus bevacizumab for hepatocellular carcinoma with WNT/β-catenin signal activation.

Atezolizumab plus bevacizumab therapy has high response rates in patients with advanced hepatocellular carcinoma (HCC). It has been reported that HCC with immune exclusion associated with the signal activation of WNT/β-catenin is resistant to immune checkpoint inhibitors; however, to the best of our knowledge, the effectiveness of atezolizumab plus bevacizumab for HCC with WNT/β-catenin signal activation has not been reported. The present study aimed to analyze the efficacy of atezolizumab plus bevacizumab for HCC with WNT/β-catenin signal activation. A total of 24 patients who underwent liver tumor biopsy for HCC were classified into WNT/β-catenin signal activation and inactivation groups according to the expression levels of β-catenin and glutamine synthetase, which are indicative of WNT/β-catenin signal activation. The differences in the clinical responses to treatment between the groups were analyzed. A total of 15 patients had HCC with WNT/β-catenin signal activation, whereas 9 patients had HCC with WNT/β-catenin signal inactivation. There were no significant differences between both groups regarding objective responses (P=0.519) and disease control (P=0.586). In the WNT/β-catenin signal activation group, the median progression-free survival rate was 6.9 months compared with 6.2 months in the WNT/β-catenin signal inactivation group (P=0.674). Although a small number of patients was included in the present study, the present findings suggested that the efficacy of atezolizumab plus bevacizumab might be unaffected by WNT/β-catenin signal activation.