The Levels of Interferon-gamma Release as a Biomarker for Non-small-cell Lung Cancer Patients Receiving Immune Checkpoint Inhibitors.

Background/Aim: The present study aimed to prospectively examine the usefulness of interferon-gamma (IFN-gamma) release (IGR) as a biomarker in non-small-cell lung cancer patients receiving immune checkpoint inhibitor treatment (ICITx). Patients and Methods: IGR was measured using enzyme-linked immunosorbent assay at four time points: within 14 days before ICI-Tx (T1), and 8 +/- 3 (T2), 22 +/- 7 (T3), and 43 +/- 7 (T4) days after ICI-Tx. Results: Twenty-nine patients were divided into three groups based on IFN-gamma levels in the IGR-positive control: Group-1 (n=8) with <10 IU/ml at T1, Group-2 (n=12) with a decrease in IFN-gamma levels to <10 IU/ml at T3 and/or T4, and Group-3 (n=9) without changes in IFN-gamma levels. Early progression and ICI-induced interstitial pneumonitis were frequently observed in Group-1 and Group-2, respectively. Group-3 exhibited more treatment cycles than the other groups. All three groups showed clear differences in clinical outcomes. Conclusion: IFN-gamma levels could be a biomarker for ICI-Tx.