Clinical predictors of response to single‑agent immune checkpoint inhibitors in chemotherapy‑pretreated non‑small cell lung cancer

Single‑agent immune checkpoint inhibitors (ICIs) are the standard option for chemotherapy‑pretreated metastatic non‑small cell lung cancer (NSCLC), however only a subset of patients responds to this treatment. The present study aimed at the development of a tool for personalized prediction of the efficacy of ICIs. The study included 181 epidermal growth factor receptor/anaplastic lymphoma kinase‑negative patients with metastatic NSCLC receiving single‑agent ICI in the second or later line of therapy. For the comparison, a total of 63 metastatic patients with NSCLC treated by chemotherapy were also analyzed. Multivariate analysis revealed that Eastern Cooperative Oncology Group performance status (ECOG PS) ≥2, never‑smoking status and the baseline neutrophil‑to‑lymphocyte ratio (NLR) ≥4.3 were associated with reduced progression‑free survival (PFS) and overall survival (OS) ECOG PS: Hazard ratio (HR)=2.09; P=0.028 and HR=2.02; P=0.035, respectively; never‑smoking: HR=3.53; P=0.007 and HR=1.80; P=0.004, respectively; NLR ≥4.3: HR=4.34; P<0.0001 and HR=4.89; P<0.0001 respectively. Patients with an NLR <4.3, who had a favorable ECOG PS (0‑1) and smoking history in the past, derived the utmost benefit from ICI n=77; objective response rate (ORR)=35%; PFS and OS: 17.1 and 33.7 months, respectively. The worst efficacy of ICI was observed in patients who had an NLR ≥4.3 coupled with poor ECOG PS and/or never‑smoking status (n=38; ORR=8%; PFS=3.2 months and OS=7.2 months). The remaining patients belonged to the group with intermediate outcomes (n=66; ORR=17%; PFS and OS: 4.3 and 12.2 months, respectively). While combination of these factors was highly predictive for ICIs, it was not associated with outcomes of chemotherapy treatment. Easily available characteristics of the patients allow for highly accurate predictions of outcomes of single‑agent ICI therapy in chemotherapy‑pretreated NSCLC.