The efficacy of immune checkpoint inhibitors (ICIs) in elderly and poor performance status (PS) patients is controversial, because clinical evidence is limited. This study aimed to find a predictive biomarker for the efficacy of anti-programmed cell death 1 (PD-1) antibodies in these patient populations. We retrospectively reviewed medical records of advanced non-small-cell lung cancer (NSCLC) patients who were ≥ 75 years of age or classified as PS 2 and received anti-PD-1 antibody treatment between December 2015 and May 2018. We evaluated the association between the efficacy of the anti-PD-1 antibody in these patients and the clinical variables thought to affect ICI efficacy. A total of 235 patients with advanced NSCLC were treated with anti-PD-1 antibodies, among whom 31 patients were ≥ 75 years of age and 22 were PS 2. A Cox proportional hazard model showed that only high levels of serum vascular endothelial growth factor (VEGF) were significantly associated with a shorter progression-free survival in patients aged ≥ 75 years and those with PS 2. Among these cohorts, the overall response rate to anti-PD-1 treatment tended to be lower when serum VEGF was high compared to patients with low serum VEGF. Our results demonstrate that serum VEGF concentration may be a negative predictive biomarker in elderly and poor PS advanced NSCLC patients receiving anti-PD-1 antibody treatment. This finding may help identify patients who will not benefit from anti-PD-1 antibody therapy.
Keywords: Anti-PD-1 antibody; Elderly; Non-small-cell lung cancer; Performance status; Vascular endothelial growth factor.