Association between tumor morphology and efficacy of atezolizumab plus bevacizumab for advanced hepatocellular carcinoma

Abstract Aim The IMbrave150 trial revealed that atezolizumab plus bevacizumab (AtezoBv) showed a higher objective response rate (ORR) in patients with advanced hepatocellular carcinoma (HCC). Although conversion therapy after AtezoBv has been recently reported, markers predictive of its efficacy, particularly radiological imaging markers, have not yet been identified. The present study focused on tumor morphological appearance on radiological imaging and evaluated whether it could be associated with AtezoBv efficacy. Methods Ninety‐five intrahepatic lesions in 74 patients who were given AtezoBv for advanced HCC were recruited for evaluation. The lesions were divided into two groups, simple nodular (SN group) and non‐simple nodular (non‐SN group), based on the gross morphology on pretreatment imaging, and retrospectively evaluated for treatment response and other relevant clinical outcomes. Results Assessing the size of individual tumors after treatment, waterfall plots showed that tumor shrinkage in the non‐SN group including 56 lesions was higher than that in the SN group comprising 39 lesions. The ORR was significantly higher in the non‐SN group (39.3% vs. 15.4%, p = 0.012). Additionally, the median time to nodular progression was longer in the non‐SN group (21.0 months vs. 8.1 months, p = 0.119) compared to the SN group. Six patients with non‐SN lesions underwent sequential local therapy. Conclusions Atezolizumab plus bevacizumab may show increased therapeutic efficacy in patients with tumors with a higher potential for aggressive oncological behavior, such as non‐SN lesions. Treatment strategies focusing on conversion therapy may be crucial in patients with non‐SN lesions.