Abstract 1719: Superior efficacy of neoadjuvant compared to adjuvant immune checkpoint blockade in non-small cell lung cancer
Authors: Cascone Tina , Hamdi Haifa , Zhang Fahao , Poteete Alissa , Li Lerong , Hudgens Courtney W. , Williams Leila J. , Wu Qiuyu , Gudikote Jayanthi , Peng Weiyi , Hwu Patrick , Wang Jing , Tetzlaff Michael , William William N. , Heymach John V. 
Published: August 2018

Abstract
Introduction: Blockade of immune checkpoints has improved clinical outcomes for patients with metastatic non-small cell lung cancer (NSCLC), but its role in the perioperative setting for early-stage disease is unclear. We generated preclinical models of resectable NSCLC expressing an antigen that permits quantitative assessment of the immune response and compared survival, tumor recurrence, and immune response after neoadjuvant or adjuvant immunotherapy.
Experimental Procedures: We transfected murine 344SQ NSCLC cells with an ovalbumin-expression plasmid to generate OVA+ cells that can be identified with an antibody against the peptide SIINFEKL bound to H-2Kb of MHC-I. We implanted 344SQ-OVA+ cells in the flank of syngeneic mice and then randomized mice with established tumors to either 3 doses of neoadjuvant IgG, anti-PD-1, anti-CTLA-4, anti-PD-1+anti-CTLA-4, or to observation. Primary tumors were resected in all mice 2 days after mice in the neoadjuvant group had received their last dose of therapy. Two days post-surgery, mice in the observation group were treated with 3 doses of adjuvant IgG, anti-PD-1, anti-CTLA-4, anti-PD-1+anti-CTLA-4. Mice were euthanized 4 weeks after injection or when moribund and their survival recorded and lung metastases counted. We determined the composition of CD3+CD8+ tumor-infiltrating lymphocytes (TILs) with flow cytometry using tetramers against SIINFEKL-specific T cell receptors and immunohistochemical staining of tumors.
Results: Single agent and combined immunotherapy significantly prolonged survival compared to controls in both neoadjuvant and adjuvant groups (p&lt;0.05). Combined therapy was superior to either monotherapy in the neoadjuvant setting (combo vs. anti-PD-1 and vs. anti-CTLA-4 p&lt;0.05), whereas there were no significant differences between combined treatment and monotherapies in the adjuvant setting. Moreover, combined therapy in the neoadjuvant setting significantly prolonged survival compared to adjuvant combined treatment (p&lt;0.05). Neoadjuvant combined therapy produced the most profound reduction in lung metastases when compared to monotherapy (combo vs. IgG, vs. anti-PD-1 and vs. anti-CTLA-4 p&lt;0.01), or to adjuvant combined treatment. Neoadjuvant combined therapy was associated with the greatest amounts of SIINFEKL-tetramer+ TILs in resected primary tumors and also with increased CD8+ TIL density in both resected primary tumors (combo vs. IgG and vs. anti-PD-1 p&lt;0.05) and secondary lung metastases (combo vs. IgG, vs. anti-PD1 and vs. anti-CTLA-4 p&lt;0.05). Functional studies investigating the immune response of tumors treated with perioperative immunotherapies are ongoing.
Conclusions: Neoadjuvant combined immune checkpoint blockade is superior to adjuvant immunotherapy at prolonging survival, reducing distal recurrence and inducing anti-tumor immunity in preclinical models of resectable NSCLC.
Citation Format: Tina Cascone, Haifa Hamdi, Fahao Zhang, Alissa Poteete, Lerong Li, Courtney W. Hudgens, Leila J. Williams, Qiuyu Wu, Jayanthi Gudikote, Weiyi Peng, Patrick Hwu, Jing Wang, Michael Tetzlaff, William N. William, John V. Heymach. Superior efficacy of neoadjuvant compared to adjuvant immune checkpoint blockade in non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1719.