Exploration of biomarkers in potentially resectable stage IIIB NSCLC patients receiving neoadjuvant chemoimmunotherapy.

Abstract

e20591 Background: Non–small cell lung cancer (NSCLC) is one of the main leading causes of cancer mortality in the world. NSCLC is incurable in most patients with potentially resectable locally advanced stage IIIB disease. Numerous studies suggest that advantageous chemoimmunotherapy is a promising treatment for resectable NSCLC. The determination of PD-L1, T-cell receptor (TCR) repertoire and tumor mutational burden (TMB) have been reported to predict the response to immunotherapy. However, the value of pathologic response determination in the context of neoadjuvant chemoimmunotherapy in resectable stage IIIB NSCLC is limited. Therefore, it is necessary to identify biomarkers for the prediction of the benefit from neoadjuvant chemoimmunotherapy in patients with potentially resectable stage IIIB NSCLC. Methods: A total of 15 patients with potentially resectable clinical stage IIIB NSCLC were enrolled into the study receiving neoadjuvant sintilimab (200mg IV Q3W) plus chemotherapy therapies for 4-6 weeks followed by surgery. All peripheral blood and tissue samples were collected and detected by using TCR repertoire sequencing before and after chemoimmunotherapy. The patients were divided into MPR group (n=5) and non-MPR group (n=10) according to MPR (<10% viable tumour at resection) as an index. Furthermore, TMB spectra of 1021-gene panels and PD-L1 immunohistochemical staining were performed in paraffin-embedded human NSCLC tissue before neoadjuvant chemoimmunotherapy. The Pearson correlation coefficient method was used to analyze correlation. The ROC analysis were performed using “pROC” R package. Results: In baseline tissue samples, the levels of TMB and NAD were higher in MPR compared with non-MPR groups (P=0.0328, P=0.015, respectively). The negative correlation was existed between pretreatment tissue TCR richness and TMB in non-MPR group (P=0.028, R=-0.66). In MPR group, TCR clones and evenness showed significant difference (P=0.00237, P=0.04658, respectively). In non-MPR group, the TCR repertoire of tissue in posttreatment showed significant difference compared with those of pretreatment, including clones (P=1.04x10-6), shannon’s diversity (P=0.00142), evenness (P=0.00433), richness (P=0.00591). The clinical data showed that MPR patients with DDR mutation had longer DFS after sintilimab plus chemotherapy therapies (18.4±5.41 months, X-squared=9.8, P=0.02034). DDR mutation, TMB and TCR richness revealed better sensitivity and specificity to classify patients achieving MPR after neoadjuvant chemoimmunotherapy (AUC=1.000, AUC=0.796, AUC=0.773, respectively). Conclusions: This study confirmed the superiority of neoadjuvant chemoimmunotherapy in patients with potentially resectable stage IIIB NSCLC in terms of MPR. TCR repertoire, TMB and DDR mutation were associated with pathologic response to neoadjuvant chemoimmunotherapy as biomarkers for effective anti-tumor immunity. Clinical trial information: ChiCTR2000040673 .