11P Decreased Monocyte-to-lymphocyte Ratio Was Associated with Satisfied Outcomes of First-Line PD-1 Inhibitors Plus Chemotherapy in Stage IIIB-IV Non-Small Cell Lung Cancer

Immunotherapy plus chemotherapy are widely used in patients with advanced non-small cell lung cancer (NSCLC) without oncogenic driver alterations. The monocyte-to-lymphocyte ratio (MLR) might predict thetreatment outcomes of ICI therapy in advanced NSCLC patients but has not yet been investigated. In addition, the cutoff of MLR is controversial. Therefore, the present study aimed to explore the associations between changes in MLR at the initial stage of treatment and clinical outcomes in advanced NSCLC patients receiving first-line PD-1 inhibitor plus chemotherapy. The present study included 139 stage IIIB-IV NSCLC patients treated with first-line PD-1 inhibitor plus chemotherapy. The blood results were assessed 10 days before initiation of combination therapy (baseline) and before the third cycle of combined therapy (time point 2). Compared to altered MLR, neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR) in baseline and in time point 2, patients were divided into decreased MLR/NLR/PLR and increased MLR/NLR/PLR groups. The ORR, PFS, and the association with the changes in blood indicators were analyzed. Patients with decreased MLR had a significantly higher ORR in the univariate (P<0.001) and multivariate (P<0.001) analyses. Decreased MLR was significantly associated with prolonged PFS in the univariate (P=0.007) and multivariate (P=0.016) analyses. Decreased NLR exhibited high ORR (P=0.001) and prolonged PFS in univariate analysis (P=0.033). Decreased PLR was associated with high ORR in univariate (P<0.001) and multivariate (P=0.017) analyses. The subgroup analyses showed that decreased MLR was significantly associated with satisfactory outcomes in patients with all PD-L1 expressions. Decreased MLR was associated with high ORR and long PFS and might have a potential predictive value in NSCLC treated with first-line PD-1 inhibitor plus chemotherapy. In addition, changes in MLR might have predictive value in all PD-L1-expressing populations. Decreased NLR and PLR also showed improved survival, suggesting that changes in NLR and PLR may be complementary to predicting prognosis.