Abstract A084: High OX-40 expression on the tumor immune infiltrate is a prognostic factor of better survival in non-small cell lung cancer

Background: OX-40 expression on tumor-infiltrating lymphocytes correlates with better survival in several human cancers, suggesting that OX-40 signals may play a critical role in establishing an antitumor immune response. To better understand the prognostic role of OX-40 expression on the tumor immune infiltrate in non small cell lung cancer (NSCLC), we have profiled 100 surgically resected tumor specimens from patients with stage I-III NSCLC with known clinico-pathological characteristics using a panel of several markers of immune suppression and activation by immunohistochemistry (IHC) and correlated them with survival outcomes and gene expression profiles. Methods: 100 formalin fixed paraffin embedded NSCLC specimens (61 adenocarcinoma, 31 squamous cell carcinoma) were stained by IHC using an automated stainer with a panel of antibodies targeting the following immune markers: OX-40, PD-L1, PD-1, CD3, CD4, CD8, CD45RO, CD57, CD68, FOXP3, Granzyme B, ICOS. PD-L1 expression was evaluated in the tumor cells using H-score (range 0-300) taking into consideration the percentage of positive cells showing membrane staining pattern (0 to 100) and intensity of the staining (0 to 3+). The remaining markers were evaluated as density of cells, defined as the number of positive cells per area regardless of the intensity. The final score for each marker was expressed as the average score of the five areas analyzed within the tumor region. mRNA expression was determined in the tumors by Illumina microarray and correlated with the IHC score by Spearman correlation test. Results: OX-40 IHC expression was localized in the membrane of the tumor immune infiltrate (median value 271, range 56 to 1246). No statistical correlation was observed in tumor immune infiltrate with high versus low OX-40 IHC expression (by median value) and gender, age, race, smoking status, stage, EGFR and KRAS-mutation status. In contrast, high OX-40 expression levels in the tumor immune infiltrate correlated with better overall survival (OS) by IHC median score (p = 0.002) and by quartile distribution analysis (p = 0.001). This statistical association was maintained in the squamous cell carcinoma subgroup by median value (p = 0.04) and quartile distribution (p = 0.001). To understand the prognostic role of the OX-40 expression in relationship with the CD3+/CD8+ immune infiltrate, we analyzed the prognostic significance of CD3+/CD8+ with or without OX-40 positivity. The patients whose tumors showed high levels of CD3, CD8 and OX-40 IHC staining in the tumor immune infiltrate had a statistically significant better OS than the counterpart with high CD3+/CD8+ but low OX-40 expression (p = 0.007). High OX-40 IHC score was associated with increased expression of immune-related genes such as CD3, INFgamma, ICOS, CD8, CCL5, EOMES, granzyme B, BTK (p Conclusion: High OX-40 IHC expression in the tumor immune infiltrate has a strong prognostic association with better OS in patients with surgically resected stage I-III NSCLC. Our study suggests the potential for OX-40 agonistic antibodies, currently in clinical development for NSCLC, to enhance the efficacy of existing checkpoint inhibition therapies. (This study was supported by the Immunotherapy Platform at M.D. Anderson Cancer Center). Citation Format: Erminia Massarelli, Edwin R. Parra, Jaime Rogriguez-Canales, Carmen Behrens, Lixia Diao, Jorge Blando, Jing Wang, Lauren A. Byers, Ignacio I. Wistuba, Padmanee Sharma, James P. Allison, John V. Heymach. High OX-40 expression on the tumor immune infiltrate is a prognostic factor of better survival in non-small cell lung cancer [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr A084.