Remaining Issues Related to Serum Cytokines in Patients with Unresectable Hepatocellular Carcinoma Treated by Atezolizumab plus Bevacizumab Combination Treatment.

Introduction: Atezolizumab plus bevacizumab (AteBev) combination treatment is widely used as first-line systemic therapy for unresectable hepatocellular carcinoma (uHCC). We aimed to clarify therapeutic issues regarding serum cytokines and the immune reaction in patients with uHCC treated with AteBev. Methods: We analyzed preserved serum from a previous prospective study on adult Japanese patients with chronic liver disease and uHCC who received AteBev treatment at our hospital. In that study, AteBev was administered intravenously every 3 weeks, and blood samples were collected before and after 3 weeks' treatment. Dynamic computed tomography was performed after 6 weeks of treatment to assess response. Results: In the prospective study, 21 of the 59 patients showed partial response (PR) and 19 patients showed stable disease, but 19 patients showed progressive disease (PD). We found that serum levels of tumor necrosis factor-alpha, interleukin (IL)-6, and soluble IL-2 receptor (IL-2R) increased significantly in the PR group, but only soluble IL-2R increased significantly in the PD group. Regulatory T cells decreased significantly in the PD group, but there was no significant change in Th1 or Th2 cells from before to after treatment in any group. As regards soluble MHC-class I, pre-treatment levels were significantly lower in the PD group than in the PR group, and serum levels increased significantly with treatment in the PD group. Conclusion: These findings reveal a need to further improve T-cell priming and to further make T cells recognize tumor antigens in uHCC. [ABSTRACT FROM AUTHOR]