P2.04-19 Neoadjuvant Chemotherapy Is Associated with Immunogenic Cell Death and Increased T Cell Infiltration in Early-Stage NSCLC

Abstract

Recent success using immune checkpoint blockade (ICB) in the metastatic setting has raised the need to understand the immune microenvironment (IME) in early-stage disease. Moreover, pre-clinical evidence suggests that cytotoxic agents can modulate this IME. A recent study conducted by our group showed that non-small cell lung cancer (NSCLC) patients who received neoadjuvant chemotherapy followed by surgery (NCT), as compared to patients who received upfront surgery (US), had higher densities of CD3+ lymphocytes and CD68+ tumor-associated macrophages (TAMs). CD3+CD4+ lymphocytes and TAMs also correlated with better clinical outcomes. In this study, we explored the relationships between NCT and the IME by harvesting tumor samples of multiple surgical NSCLC cohorts. The PROSPECT microarray database was queried in NCT (n=45) and US (n=200) patients to investigate differentially expressed genes related to immunogenic cell death (ICD), susceptibility to CD8+ T cell and NK cell cytotoxicity, priming of antigen presenting cells, immunosuppressive enzymes and intra-tumoral cytokines. Available data from the ImmunogenomiC prOfiling of NSCLC (ICON) and other surgical NSCLC cohorts was evaluated to determine: 1) differential immune profiling using FACS (NCT=17; US=39) and multiplex IHC imaging (NCT=10; US=72); 2) plasma circulating cytokines (NCT=18; US=73); 3) tumor mutational burden (TMB) (NCT=40; US=61). Participants who received NCT or US were excluded according to these criteria: 1) concurrent treatment in addition to NCT; 2) sarcomatoid and small cell histologies; 3) clinical or pathological TNM Stage 4 disease; 4) synchronous malignancies other than lung. PROSPECT NCT patients expressed increased damage-associated molecular pattern (DAMP) genes (HSPA2, HSPA4, HSPE1, and S100A2; p<0.05) and T cell-related chemotaxis and antigen presentation genes (CXCR7, CD1A; p<0.05). Concordantly, the ICON cohort FACS results showed that NCT patients display increases in: 1) infiltration of CD8+ T cells (p=0.004); 2) proliferating Ki67+CD8+ T cells (p=0.02); 3) tissue resident memory CD8+CD103+ (p=0.02) and CD4+CD103+ non-Treg cells (p=0.01). Trends from the ICON multiplex IHC also highlighted increases in CD8+ T cells (p=0.09), CD20+ cells (p=0.08), as well as PD-L1+ malignant cells (p=0.08) and PD-L1+ TAMs (p=0.08) in NCT patients, the latter finding being supported by increased circulating MCP-1 (p=0.03). TMB was similar between NCT and US groups (p=0.912). Our data provides the first evidence of ICD (i.e., increased DAMP gene expression) following NCT in human early-stage NSCLC. Furthermore, our data highlights the association of NCT with a favorable IME (i.e., increased T cell infiltration), supporting the rationale of NCT and ICB combinations in localized NSCLC.