Effect of PD-1/PD-L1 immune checkpoint inhibitor in squamous and nonsquamous non-small cell lung cancer: A systematic review and meta-analysis

Abstract

Background

The effects of programmed cell death protein 1/programmed cell death ligand 1 (PD-1/PD-L1) immune checkpoint inhibitors (ICIs) in patients with squamous and nonsquamous non-small cell lung cancer (NSCLC) remain controversial. We conducted a meta-analysis to summarize the existing evidence on this topic.

Methods

We searched PubMed, Medline, and Embase for studies published before December 1, 2022, comparing PD-1/PD-L1 ICIs with docetaxel in squamous and nonsquamous NSCLC patients in any language. The different hazard ratio (HR) values for overall survival (OS) and progression-free survival (PFS) were calculated in this study.

Results

A total of seven studies were identified. In a summary analysis of all studies, the HR values of OS in patients with nonsquamous and squamous NSCLC were 0.73, 95% confidence interval (CI): 0.67–0.79 and 0.70, 95% CI: 0.62–0.79, respectively. In patients with PD-L1 expression levels of 1% or higher, the HR values of OS in nonsquamous and squamous NSCLC patients were 0.60, 95% CI: 0.49–0.74 and 0.72, 95% CI: 0.54–0.96, respectively. The HR values of OS in nonsquamous and squamous NSCLC patients with PD-L1 expression levels of 5% or higher were 0.46, 95% CI: 0.35–0.59 and 0.55, 95% CI: 0.39–0.79, respectively. In nonsquamous and squamous NSCLC patients with PD-L1 expression levels of 10% or higher, the HR values of OS were 0.42, 95% CI: 0.32–0.54, and 0.53, 95% CI: 0.36–0.78, respectively.

Conclusion

The meta-analysis demonstrated possible evidence that there was different efficacy of PD-1/PD-L1 ICIs on OS in squamous and nonsquamous NSCLC patients with different PD-L1 expression levels. Subgroup analysis showed that there was a greater OS benefit in patients with nonsquamous NSCLC.