Interferon-γ predicts the treatment efficiency of immune checkpoint inhibitors in cancer patients

Purpose Immune checkpoint inhibitors (ICIs) have improved the prognosis of cancer patients significantly with few predictive makers for treatment efficiency. Since interferon-gamma (IFN-γ) displayed its association with immunotherapy, we explored the correlation between IFN-γ and the efficacy of ICIs in tumor treatment. Methods We retrospectively examined cancer patients who received immune checkpoint inhibitors as first-line therapy at the Fourth Hospital of Hebei Medical University. The patients were divided into a low concentration group of IFN-γ (≤ 1.2 pg/mL) and a high concentration group (≥ 1.3 pg/mL) to evaluate the efficacy, which was indicated by the objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS) and overall survival (OS). Results Thirty-five patients with low IFN-γ and 56 patients with high IFN-γ were involved in the evaluation, and the DCR was significantly different between these two groups ( p = 0.009) with a high group of 81.4% (95% CI 69–94%) and a low group of 51.9% (95% CI 32–72%). The subsequent Kaplan–Meier survival analysis showed that the high IFN-γ patients displayed longer median OS than that of the low IFN-γ patients ( p = 0.049), while no statistical difference existed for PFS ( p = 0.971). The multivariate analysis also confirmed that the high IFN-γ level was independently associated with a better prognosis (HR: 0.318 95% CI 0.113–0.894, p = 0.030). Conclusions Basal serum IFN-γ levels were associated with the DCR and OS of cancer patients with higher IFN-γ exhibiting beneficial efficiency for ICIs treatment.