Relationship between Plasma IP-10/CXCL10 Levels and the Initial Therapeutic Response in Patients Treated with Atezolizumab plus Bevacizumab for Unresectable Hepatocellular Carcinoma

Atezolizumab plus bevacizumab combination therapy (AB) was the first-line treatment for unresectable hepatocellular carcinoma (u-HCC). IFN-γ-induced protein 10 (IP-10/CXCL10) is a chemokine to inhibit HCC proliferation by promoting the migration of cytotoxic T cells. We focused on the relationship between plasma IP-10/CXCL10 levels and the initial therapeutic response in patients receiving AB therapy.Forty-six patients receiving AB therapy were enrolled. Plasma IP-10/CXCL10 levels were measured at baseline, 3-7 days, 3 weeks, 6 weeks, and 8-12 weeks after the start of AB therapy. The initial therapeutic response was evaluated at 8-12 weeks.The baseline IP-10/CXCL10 levels of partial response (PR) group was higher than that of stable disease (SD) or progressive disease (PD) group. Patients with the baseline IP-10/CXCL10 of 84 pg/mL or higher were likely to present PR than patients below (71 vs. 35%, p = 0.031), but prediction of PD using the baseline IP-10/CXCL10 levels was difficult. In contrast, IP-10/CXCL10 ratio of the PR group was lower than that of the SD/PD group at 3, 6, and 8-12 weeks. Patients with the 3, 6, and 8-12 weeks IP-10/CXCL10 ratio of 1.3, 0.4, and 0.4 or lower were likely to present PR than patients with ≥1.3, 0.4, and 0.4 (88, 35, 35 vs. 30, 3.8, 0%, p < 0.001, 0.011, 0.002). In other hand, the 3, 6, and 8-12 weeks IP-10/CXCL10 ratio for PD group was higher than that for non-PD group. Patients with the 3, 6, and 8-12 weeks IP-10/CXCL10 ratio of 1.3, 1.7, and 1.9 or higher were likely to present PD than patients below (85, 62, 57 vs. 32, 23, 14%, p = 0.002, 0.034, 0.009).High baseline IP-10/CXCL10 levels may be associated with better outcome, and high IP-10/CXCL10 ratio after 3-12 weeks may be associated with worse outcome in u-HCC patients receiving AB therapy.