Abstract 3194: Immune biomarkers in the tumor microenvironment associated with response in pre-treatment non-small cell lung cancer (NSCLC) samples with second line immunotherapy follow-up data

Surgical first line resection samples are frequently accessed to select patients for immune checkpoint inhibitor (ICI) therapy, often based on expression of PD-L1 measured by immunohistochemistry (IHC). However, while PD-L1 expression may enrich for response to ICIs, other immune parameters in the tumor microenvironment will likely contribute to outcome. To assist in the identification of biomarker(s) that might predict response to ICIs, we have analyzed a cohort of pre-treatment NSCLC cases for which second line immunotherapy clinical follow-up data are available. Formalin fixed paraffin embedded (FFPE) tumor samples were analysed (i) by single-plex IHC for CD3, CD8, CD68, CD163 and PD-L1, plus digital image analysis (CellProfilerTM), and (ii) profiled for multidimensional biomarkers using the targeted RNA sequencing and machine-learning platform ImmunoPrism® from Cofactor Genomics. Clinical follow-up data indicated objective response to ICI therapy for 4/18 patients, with average time from initial diagnosis to ICI treatment of 33.5 ± 29.6 months (mean ± SD). While CD68+ macrophage frequencies evaluated by IHC did not differ significantly between responder and non-responder populations, significant increases in T cell numbers (CD3: 2.3-fold; CD8: 2.7-fold; both p Citation Format: Milan Bhagat, Woo Ho Kim, Lorenzo Memeo, Lorenzo Colarossi, Natalie LaFranzo, Steve Daniel, Christopher Womack, Marie Cumberbatch. Immune biomarkers in the tumor microenvironment associated with response in pre-treatment non-small cell lung cancer (NSCLC) samples with second line immunotherapy follow-up data [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3194.