Predictors of Survival Benefit From Immune Checkpoint Inhibitors in Patients With Advanced Non-small-cell Lung Cancer: A Systematic Review and Meta-analysis

Randomized trials showed inconsistent survival benefit with immune checkpoint inhibitors (ICIs) in patients with advanced non-small-cell lung cancer with low programmed death-ligand 1 (PD-L1) tumors (< 1%) and in elderly patients (> 65 years old) and never-smokers. We conducted a systematic review and meta-analysis to assess the efficacy of single agent ICIs in these pre-defined subgroups. The electronic databases PubMed and EMBASE were searched for relevant randomized trials. Pooled hazard ratios (HRs) for overall survival (OS) and progression-free survival (PFS) were meta-analyzed using the generic inverse variance method. Nine studies were included. Compared with chemotherapy, the use of single agent ICIs in the second-line setting reduced the risk of death independent of PD-L1 expression (HR, 0.79; 95% confidence interval [CI], 0.66-0.96 and HR, 0.75; 95% CI, 0.61-0.85 for patients with PD-L1-negative and -positive tumors, respectively). Yet, a PFS benefit was only seen in patients with PD-L1-positive tumors. Similarly, an OS benefit was seen in patients independent of age (HR, 0.79; 95% CI, 0.69-0.89 and HR, 0.76; 95% CI, 0.66-0.88 for elderly and non-elderly patients, respectively). Conversely, an OS benefit was only seen in ever-smokers (HR, 0.78; 95% CI, 0.68-0.89) and a detrimental effect on PFS in never-smokers (HR, 1.68; 95% CI, 1.07-2.63). Patients with advanced non-small-cell lung cancer derive a survival benefit from ICIs independent of tumor PD-L1 expression and age, particularly in the second line, whereas never-smokers do not. Caution should be exercised when offering single-agent ICIs to elderly patients in the first line, and other treatment options should be considered in never-smokers.