C-reactive protein and lactate dehydrogenase serum levels potentially predict the response to checkpoint inhibitors in patients with advanced non-small cell lung cancer.

Background: Programmed cell death-ligand 1 (PD-L1) expression and other biomarkers are not completely reliable predictors of the response to checkpoint inhibitors in patients with advanced non-small cell lung cancer (NSCLC). We investigated the value of peripheral serological inflammatory indicators and their combination in predicting the prognosis of patients with advanced NSCLC treated with checkpoint inhibitors. Methods: This study retrospectively analyzed 116 NSCLC patients treated with anti-programmed cell death protein 1 (PD-1)/PD-L1 monoclonal antibodies. Clinical data of the patients were collected before treatment. X-tile plots determined the optimal cut-point for C-reactive protein (CRP) and lactate dehydrogenase (LDH). A survival analysis was performed using the Kaplan-Meier method. Multi-factor Cox regression analysis was used to evaluate the statistically significant factors identified in the univariate analysis. Results: The X-tile plots show the cut-points of CRP and LDH were 8 mg/L and 312 U/L, respectively. Univariate analyses showed high baseline serum LDH and low CRP levels were associated with adverse progression-free survival (PFS). Multivariate analyses indicated that CRP (HR, 0.214, 95% CI: 0.053-0.857, P=0.029) could be a predictive indicator for PFS. In addition, we evaluated the combination of CRP and LDH, and univariate analyses showed that patients with high CRP and low LDH exhibited significantly better PFS than those in the other groups. Conclusions: Baseline levels of serum CRP and LDH have the potential to become a convenient clinical tool to predict response to immunotherapy in advanced non-small cell lung cancer.