RESUMEN
BACKGROUND: VeriStrat test is a serum assay which uses a mass spectrometry (MS)-based proteomic signature derived from machine learning. It is currently used as a prognostic marker for patients with non-small cell lung cancer (NSCLC) receiving chemotherapy. However, little is known about its role for NSCLC patients receiving immune checkpoint inhibitors (ICIs). METHODS: This is a retrospective study that includes 47 patients with advanced stage NSCLC without an activating EGFR mutation, who underwent the VeriStrat test from 2016 to 2018. Spectra from blood samples were evaluated to assign patients into the VeriStrat 'Good' (VS-G) or VeriStrat 'Poor' (VS-P) risk group. The clinical outcomes of 32 patients who received programmed cell death 1 (PD-1) inhibitors nivolumab or pembrolizumab were analyzed by VeriStrat status. RESULTS: The VS-G group demonstrated significantly higher progression-free survival (PFS) and overall survival (OS) compared to the VS-P group among overall NSCLC patients regardless of treatment (median PFS of 7.1 vs. 4.2 months, P=0.013, and median OS, not reached vs. 17.2 months, P=0.012). Among NSCLC patients treated with ICIs, VS-G classification was associated with significantly increased PFS in comparison to VS-P classification (median PFS of 6.2 vs. 3.0 months, P=0.012), while the differences in OS trended towards significance (median OS, not reached vs. 16.5 months P=0.076). Multivariate analysis showed that the VeriStrat status was significantly correlated with PFS and OS in NSCLC patients treated with ICIs (P=0.017, P=0.034, respectively). CONCLUSIONS: MS-based serum proteomic signature has potential as a biomarker for survival outcome in NSCLC patients receiving immunotherapy.
RESUMEN
BACKGROUND: Tissue tumor mutational burden (TMB) has emerged as a potential biomarker predicting response to anti-programmed cell death-1 protein receptor (PD-1)/programmed cell death-1 protein ligand (PD-L1) therapy, but few studies have explored using circulating tumor DNA (ctDNA) TMB in non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: A total of 136 patients with NSCLC with ctDNA testing were retrospectively evaluated from a single institution, along with a validation cohort from a second institution. ctDNA TMB was derived using the number of detected mutations over the DNA sequencing length. RESULTS: Higher ctDNA TMB was significantly correlated with smoking history (p < .05, chi-squared test). Among patients treated with immune checkpoint inhibitors (n = 20), higher ctDNA TMB was significantly correlated with shorter progressive free survival (PFS) and overall survival (OS; 45 vs. 355 days; hazard ratio [HR], 5.6; 95% confidence interval [CI], 1.3-24.6; p < .01, and OS 106 days vs. not reached; HR, 6.0; 95% CI, 1.3-27.1; p < .01, respectively). In a small independent validation cohort (n = 12), there was a nonsignificant numerical difference for higher ctDNA TMB predicting shorter OS but not PFS. ctDNA TMB was not correlated with RECIST tumor burden estimation in the subset of patients treated with immune checkpoint blockade. CONCLUSION: The findings indicate that higher ctDNA TMB, at the current commercial sequencing length, reflects worse clinical outcomes. IMPLICATIONS FOR PRACTICE: Biomarkers to identify patients who will respond to immune checkpoint blockade are critical. Tissue tumor mutational burden (TMB) has emerged as a viable biomarker to predict response to anti-PD-1/PD-L1 therapy, but few studies have explored the meaning and potential clinical significance of noninvasive, blood-based TMB. Here, we investigated circulating tumor DNA (ctDNA) TMB and present data demonstrating that current ctDNA TMB may reflect tumor burden and that ctDNA panels with a greater number of mutations may be necessary to more accurately reflect tissue TMB.