WNT/β-catenin Signaling and CD8+ Tumor-infiltrating Lymphocytes in Tremelimumab Plus Durvalumab for Advanced Hepatocellular Carcinoma.

Background/aim: Tremelimumab plus durvalumab is an approved first-line therapy for advanced hepatocellular carcinoma (HCC). Previous studies identified WNT/β-catenin mutations or CD8+ tumor-infiltrating lymphocytes (TILs) as biomarkers that can predict responsiveness to immune checkpoint inhibitor therapy in HCC. However, biomarkers for effectiveness of tremelimumab plus durvalumab in HCC have not been reported. This study investigated whether evaluation of WNT/β-catenin signaling and CD8+ TILs by immunohistochemical staining of tumor biopsy tissues can predict the response to tremelimumab plus durvalumab in patients with HCC.

Patients and methods: Fifteen HCC patients who underwent tumor biopsies were classified into three groups based on WNT/β-catenin signal activation and CD8+ TIL infiltration. The clinical responses to treatment in the groups were evaluated.

Results: Four patients had HCC with WNT/β-catenin signal inactivation and high-level CD8+ TIL infiltration, four patients had HCC with WNT/β-catenin signal activation and low-level CD8+ TIL infiltration, and seven patients had WNT/β-catenin signal activation and high-level CD8+ TIL infiltration or WNT/β-catenin signal inactivation and low-level CD8+ TIL infiltration. A better response rate was observed in the WNT/β-catenin signal inactivation and high-level CD8+ TIL infiltration group, and a worse response rate was observed in the WNT/β-catenin signal activation and low-level CD8+ TIL infiltration group.

Conclusion: Although the present study involved a small number of patients, the findings suggest that the efficacy of tremelimumab plus durvalumab may be affected by WNT/β-catenin signaling and CD8+ TIL infiltration.