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-gamma) levels and clinical outcomes in non-small-cell lung cancer (NSCLC) patients receiving immune checkpoint inhibitors (ICIs). Patients and Methods: Sample collection for IFN-gamma 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-gamma levels at T1. Results: Median progression-free survival in the Higher group was significantly longer than that in the Lower group. IFN-gamma levels in the non-progression disease group were significantly higher than those in the progression disease group. IFN-gamma levels at T1 in patients with immune-related adverse events were significantly lower compared to those at T3. Conclusion: IFN-gamma could be a biomarker for NSCLC patients receiving ICIs.