Background: A proinflammatory diathesis, as measured by the neutrophil to lymphocyte ratio (NLR), heralds an adverse disease course for non-small cell lung cancer (NSCLC).

Methods: This post hoc analysis used data from the phase 3 OAK trial (NCT02008227), which randomized previously treated patients with NSCLC to atezolizumab or docetaxel. The main objective was assessing the differential impact of the pretreatment NLR on overall survival according to the treatment modality. In addition, patients' genomic characteristics were assessed according to their inflammatory status with a circulating free DNA (cfDNA) next-generation sequencing (NGS) analysis.

Results: In all, 600 and 575 patients with NLR data were included in the atezolizumab and docetaxel cohorts, respectively, with a median NLR of 4 (interquartile range, 2.6-6.7) for the pooled population. An NLR ≥4 was associated with a positive smoking status (88.6% vs. 78.1%; p < .01), male sex (66.4% vs. 57.6%; p = .01), a worse performance status (71.3% vs. 55.2%; p < .01), a higher number of metastatic sites (63.2% vs. 51.6%; p = .01), squamous histology (32.1% vs. 21.4%; p < .01), and tissue KRAS mutations (30% vs. 18.7%; p = .02) but not with programmed death ligand 1 (PD-L1) expression or the tissue epidermal growth factor receptor (EGFR)/anaplastic lymphoma kinase (ALK) status. A pretreatment NLR ≥4 was more strongly associated with mortality after atezolizumab (adjusted hazard ratio [HR], 1.64; 95% confidence interval [CI], 1.35-2.01) versus docetaxel (HR, 1.32; 95% CI, 1.08-1.60; multivariable [MVA] interaction p = .08). The HR for an increased risk of death for PD-L1-negative/NLR ≥4 patients (compared with PD-L1-positive/NLR <4 patients) was significantly higher in the atezolizumab cohort (MVA interaction p = .01). The exclusion of EGFR/ALK-positive patients further increased the prognostic ability of the baseline NLR in favor of atezolizumab (MVA interaction p = .02). Pretreatment cfDNA data from NGS showed that patients with a high blood tumor mutation burden (cutoff, 16 mut/Mb) had a higher median NLR (4.6 vs. 3.7; p = .01). After adjustments for multiple comparisons, none of the selected variants of interest (EGFR, KRAS, TP53, KEAP1, STK11, SMARCA4, ARID1A, and targeted DNA damage response and repair genes) were significantly associated with the NLR.

Conclusions: A low baseline NLR identified patients with NSCLC who derived a greater survival benefit from atezolizumab in comparison with those identified in the docetaxel cohort. The NLR could complement PD-L1 expression in tailoring treatment in this setting.