Therapy Line and Associated Predictors of Response to PD-1/PD-L1-Inhibitor Monotherapy in Advanced Non-small-Cell Lung Cancer: A Retrospective Bi-centric Cohort Study

BACKGROUND: Evidence on PD-1/PD-L1-directed immune checkpoint inhibitor (ICI) therapy for advanced non-small-cell lung cancer (NSCLC) is mainly based on clinical trials in first- or second-line settings. OBJECTIVE: We aimed to investigate response and prognostic factors with special regard to third- or later-line therapy. PATIENTS AND METHODS: We retrospectively analyzed all patients who had received ICI monotherapy with nivolumab, pembrolizumab, or atezolizumab for advanced NSCLC. Computed tomography evaluations were analyzed using response evaluation criteria in solid tumors (RECIST, version 1.1). Kaplan–Meier analyses were conducted to calculate progression-free (PFS) and overall (OS) survival; the impact of influencing variables was evaluated using uni- and multivariate Cox-regression analyses. RESULTS: Among 153 patients (59% men, mean age 66 years), median PFS was 4 months [mo; 95% confidence interval (95% CI) 3–5], OS was 13 mo (10–17), and objective response rate (ORR) was 22%. Therapy line ≥ 3 was associated with significantly inferior PFS (p = 0.003) and OS (p = 0.001). In first-line therapy PFS, OS, and ORR were 7 mo (3–11), 17 mo [9–not evaluable (n.e.)], and 36%; in second-line 4 mo (3–7), 18 mo (13–n.e.) and 19%, and in ≥ third-line 2 mo (1–3), 9 mo (4–12), and 13%. PFS was significantly influenced by PD-L1 expression in first-line therapy (p = 0.006). In ≥ third-line patients, Eastern Cooperative Oncology Group (ECOG) performance status significantly affected PFS and OS (both p < 0.001). CONCLUSIONS: Third- or later-line single-agent anti-PD-1/PD-L1 therapy is less efficacious as compared to first- and second-line treatment. In that setting, ECOG performance status predominates known predictors like PD-L1 expression or presence of an alteration in EGFR or ALK.