Changes in Serum Interleukin-8 Levels Predict Response to Immune Checkpoint Inhibitors Immunotherapy in Unresectable Hepatocellular Carcinoma Patients.

Background: Effective biomarkers are needed to predict the efficacy of immune checkpoint inhibitors (ICIs) therapy in hepatocellular carcinoma (HCC). We evaluated the early changes in serum interleukin-8 (IL-8) levels as a biomarker of response to ICIs in patients with unresectable HCC.

Methods: Eighty patients who received ICIs therapy alone or in combination with other treatments for unresectable HCC were included. Serum was collected at baseline and 2-4 weeks after the first dose. Serum IL-8 levels were measured using by ELISA.

Results: In the progressive disease (PD) group, serum IL-8 levels increased significantly before the second dose of ICIs therapy compared with baseline levels ( < 0.001). Early changes in serum IL-8 levels were significantly associated with the response to ICIs therapy ( < 0.001). A cutoff value of 8.1% increase over the baseline most effectively predicted the response to ICIs. Increases in serum IL-8 levels > 8.1% indicated the uselessness of ICIs immunotherapy in patients with unresectable HCC. Patients with increases in serum IL-8 levels > 8.1% had significantly shorter overall survival (OS) and progression-free survival (PFS) than those with increases in serum IL-8 levels ≤ 8.1% ( < 0.001). Increases in serum IL-8 levels > 8.1% were independent prognosticators of worse OS ( = 0.003) and PFS ( < 0.001).

Conclusion: Early changes in serum IL-8 levels, measured only 2-4 weeks after starting therapy, could predict the response to ICIs therapy, as well as OS and PFS of patients with unresectable HCC. Increases in serum IL-8 levels > 8.1% indicated the uselessness of ICIs immunotherapy and predicted worse OS and PFS.