Serum osteopontin predicts the response to atezolizumab plus bevacizumab in patients with hepatocellular carcinoma

Background Combination therapy with anti-programmed death-ligand 1 and anti-vascular endothelial growth factor (VEGF) antibodies has become the standard treatment for un-resectable hepatocellular carcinoma (uHCC). We aimed to identify predictive circulating biomarkers for the outcome/response of the combination therapy in uHCC patients. Methods This prospective multicenter study enrolled 70 patients with uHCC who received atezolizumab and bevacizumab (Atez/Bev). We evaluated 47 circulating proteins in sera before and after 1 and 6 weeks of Atez/Bev therapy by multiplex bead-based immunoassay and ELISA. As controls, we analyzed the sera from 62 uHCC patients before treatment of lenvatinib (LEN) and healthy volunteers (HVs). Results The disease control rate was 77.1%. Median progression-free survival (PFS) was 5.7 months (95% confidence interval [CI] = 3.8–9.5). The pretreatment levels of osteopontin (OPN), angiopoietin-2, VEGF, S100–calcium-binding protein A8/S100–calcium-binding protein A9, soluble programmed cell death-1, soluble CD163, and 14 cytokines/chemokines were higher in patients with uHCC than in HVs. Among these, pretreatment OPN levels were higher in PD group than in non-PD group for Atez/Bev. The PD rate was higher in high OPN group than in low OPN group. Multivariate analysis identified high pretreatment OPN and high α‐fetoprotein levels as independent predictors of PD. In the sub-analysis of Child–Pugh class A patients, PFS was also shorter in the high OPN group than in the low OPN group. Pretreatment OPN level was not associated with treatment response for LEN. Conclusion High serum OPN levels were associated with poor response to Atez/Bev in patients with uHCC.