Duruisseaux M, et al. - Given that a substantial percentage of patients with advanced non-small-cell lung cancer (NSCLC) remain non-responsive to anti-programmed death-1 (PD-1) treatment, researchers examined if the use of DNA methylation profiles could allow determination of the efficacy of anti-PD-1 treatment in these patients. Findings suggested that the epigenetic milieu of NSCLC tumors may allow for the identification of patients who are most likely to benefit from nivolumab or pembrolizumab treatments. The investigators further concluded that the methylation status of forkhead box P1 (FOXP1) could be associated with validated predictive biomarkers (eg, PD-L1 staining, mutational load) to better select patients who will experience clinical benefit with PD-1 blockade, and its predictive value should be evaluated in prospective studies.

Methods

• Adult patients who had histologically proven stage IV NSCLC and had been exposed to PD-1 blockade during the course of disease were recruited from 15 hospitals in France, Spain, and Italy.
• The study structure comprised a discovery cohort and two validation cohorts; the discovery cohort was to investigate the correlation between epigenetic features and clinical benefit with PD-1 blockade, and the validation cohorts were to determine the validity of the assumptions.
• Based on a microarray DNA methylation signature (EPIMMUNE), an epigenomic profile was established first in a discovery set of tumor samples from patients treated with nivolumab or pembrolizumab.
• Researchers validated the EPIMMUNE signature in an independent group of patients.
• Using a single-methylation assay, they validated a derived DNA methylation marker in a validation cohort of patients.
• Progression-free survival (PFS) and overall survival (OS) were the main study outcomes.
• The Kaplan-Meier method was used to estimate PFS and OS, and the log-rank test was used to calculate the differences between the groups.
• They investigated the variables independently associated with PFS and OS via constructing a multivariate Cox model.

Results

• The investigators obtained samples from 142 patients between June 23, 2014, and May 18, 2017: 34 in the discovery cohort, 47 in the EPIMMUNE validation cohort, and 61 in the derived methylation marker cohort (the T-cell differentiation factor FOXP1).
• In patients with stage IV NSCLC treated with anti-PD-1 agents, researchers noted an association of the EPIMMUNE signature with improved PFS (hazard ratio [HR] 0.010; 95% CI: 3.29?×?10⁻⁴ to 0.0282; P=0.0067) and OS (HR: 0.080; 95% CI: 0.017 to 0.373; P=0.0012).
• They did not observe any evident associations of the EPIMMUNE-positive signature with PD-L1 expression, the presence of CD8+ cells, or mutational load.
• EPIMMUNE-negative tumors were enriched in tumor-associated macrophages and neutrophils, cancer-associated fibroblasts, and senescent endothelial cells.
• The EPIMMUNE validation cohort showed improved PFS in association with the EPIMMUNE-positive signature (HR: 0.330; 95% CI: 0.149 to 0.727; P=0.0064).
• The FOXP1 validation cohort showed improved PFS (HR: 0.415; 95% CI: 0.209 to 0.802; P=0.0063) and OS (HR: 0.409; 95% CI: 0.220 to 0.780; P=0·0094) in correlation with the unmethylated status of FOXP1.
• The EPIMMUNE signature and unmethylated FOXP1 were not associated with clinical benefit in lung tumors that did not receive immunotherapy.