Significance of Quantitative Interferon-gamma Levels in Non-small-cell Lung Cancer Patients' Response to Immune Checkpoint Inhibitors.

BACKGROUND/AIM: We aimed to study the association between the quantitative interferon-gamma (IFN-γ) levels and clinical outcomes in non-small-cell lung cancer (NSCLC) patients receiving immune checkpoint inhibitors (ICIs). PATIENTS AND METHODS: Sample collection for IFN-γ release assay (IGRA) was performed within 14 days before treatment (T1), on day 22±7 (T3), and on day 43±7 (T4). The stored specimens over 10 IU/ml in IGRA were re-examined using the dilution method (with saline as the dilution medium). The patients were classified into Lower and Higher groups by 7.06 IU/ml as a cut-off of IFN-γ levels at T1. RESULTS: Median progression-free survival in the Higher group was significantly longer than that in the Lower group. IFN-γ levels in the non-progression disease group were significantly higher than those in the progression disease group. IFN-γ levels at T1 in patients with immune-related adverse events were significantly lower compared to those at T3. CONCLUSION: IFN-γ could be a biomarker for NSCLC patients receiving ICIs.