Impact of Immune Checkpoint Inhibitors with or without a Combination of Tyrosine Kinase Inhibitors on Organ-Specific Efficacy and Macrovascular Invasion in Advanced Hepatocellular Carcinoma

Introduction: The tumor microenvironments of different organs often differ and thus may affect the immunotherapy response. Objective: This study elucidated that the efficacy of programmed cell death protein-1 (PD-1) inhibitors varies across different metastatic sites among individuals with advanced hepatocellular carcinoma (HCC). Methods: We retrospectively analyzed treatment outcomes in advanced HCC patients receiving PD-1 inhibitors with or without a combination of tyrosine kinase inhibitors (TKIs). Both the overall response rate (ORR) and organ-specific response rate (OSRR) were assessed using Response Evaluation Criteria in Solid Tumors 1.1 criteria. A survival analysis and its predictors were determined using a multivariate analysis. Results: We analyzed 42 advanced HCC patients (median age: 58.0 years; 78.6% males). Thirty (71.4%) patients were sorafenib-experienced and 27 (64.3%) were administered a combination of TKIs. The ORR was 14.3% and the disease control rate was 33.3%. The median overall survival (OS) and progression-free survival (PFS) were 12.0 and 2.9 months, respectively. The OSRRs were 14.7, 23.8, 28.6, and 50.0% for the liver, lungs, lymph nodes, and vascular response, respectively. The multivariate analysis indicated that the vascular response was significantly associated with PFS. ECOG performance status was a significant independent predictor of OS. Conclusions: PD-1 inhibitors improved OS and PFS in advanced HCC patients. Their efficacies varied among the metastatic locations regardless of the combination of TKIs; in particular, a higher response in vascular metastases was correlated with a longer PFS. PD-1 inhibitors may deliver a synergistic benefit in patients undergoing traditional therapy and progression in other organs in vascular responders.