Efficacy of immune checkpoint inhibitors according to programmed cell death-ligand 1 expression in patients with non-small cell lung cancer and brain metastasis: A real-world prospective observational study

Introduction: Studies have shown the antitumor efficacy of immune checkpoint inhibitors (ICI) in patients with non-small cell lung cancer (NSCLC) and brain metastases (BM). However, it is unclear whether the efficacy of ICI is similar between patients with and without BM. It is yet unclear whether the efficacy of ICI in patients with BM increases with higher levels of programmed cell death-ligand 1 (PD-L1) expression, as observed in patients without BM.

Methods: We compared the outcomes of ICI treatment between patients with and without BM using a cohort containing 1741 prospectively enrolled patients with lung cancer. We investigated whether there were differences in the outcomes of ICI based on PD-L1 expression levels between these patients.

Results: We enrolled 240 patients with NSCLC with or without BM who were treated with ICI or both chemotherapy and ICI. There were no significant differences in overall survival (OS) between all patients with or without BM (p = 0.489). However, OS was significantly shorter in patients with BM than in those without in the PD-L1 ≥ 50% group (16.5 M vs. 30.6 M, p = 0.003) but not in the PD-L1 ≥ 1% or negative group. BM was an independent poor prognostic factor for OS (hazard ratio: [95% confidence interval], 2.045; [1.058-3.953], p = 0.033) in the PD-L1 ≥ 50% group.

Conclusion: Our study indicated that the outcomes of patients with or without BM treated with ICI were not significantly different. The efficacy of ICI in patients with PD-L1 expression ≥50% would be lower in patients with BM than in those without.