Abstract 6396: Ex vivo 3D micro tumor testing to assess chemotherapy and immunotherapy responses for NSCLC patients
Authors: Koedoot Esmee , Sijsenaar Timothy J. , Ceton Lieke J. , van der Meer Dieudonné J. , van Brakel Thomas J. , van Zwam Peter , Geraedts Erica , Vader Willemijn , Smit Egbert F. , Steinbusch Laurie C. , Steendam Christi M. 
Published: March 2024

Abstract
Background: Systemic treatment options for NSCLC patients consists of chemo-, targeted or immunotherapy. Although predictive biomarkers can guide treatment decisions, response prediction for chemo- and immunotherapy is still a challenge. Recent studies showed the potential of functional testing to assess patient sensitivity to drugs in various cancers, but NSCLC is lacking. This study reports the feasibility of ex vivo 3D micro lung tumor testing with native tumor microenvironment (TME) to enable treatment sensitivity profiling for all drug classes in parallel.
Methods: Fresh NSCLC tumor tissue was collected from pleural fluid stage IVa/b (N=24) or resected primary tumor for stage I-III disease (N=11). Tumor clusters were isolated and exposed to drugs, while preserving the TME. Thirteen therapies were included, including cisplatin, pembrolizumab, osimertinib, and positive control for immune sensitivity (SEA). Morphological features were extracted from high-throughput 3D imaging data. Chemo- and targeted therapy sensitivity was based on AUC comparison of fitted dose-response curves. Immunotherapy sensitivity was classified on percentage and statistical significance of tumor killing, immune cell proliferation and cytokine profiling.
Results: The overall assay success rate for solid samples was 64% (7/11), with 100% (4/4) success after protocol optimization. For pleural fluids, the overall success rate was 33% (8/24), caused by many samples arriving without tumor content (13/24, 54%). Excluding these samples, a technical success rate of 73% (8/11) was obtained. The assay was robust and reproducible (mean Z’ = 0.38, CV = 16.1%). Results were delivered in two weeks and on average, eight treatments were tested in parallel per sample.
Patient-specific response profiles were observed for chemo-, targeted and immunotherapy. General immunotherapy sensitivity (SEA) was measured in 50% (6/12) of the tissues. Distinct responses were observed for the different immunotherapies: 33% (4/12), 17% (2/12) and 8% (1/12) of the patients responded to pembrolizumab, atezolizumab and/or ipilimumab, respectively. Strong response to osimertinib was observed in a patient with EGFR exon 19 mutation (AUC = 0.26) versus resistance in a WT patient (AUC=0.92).
Conclusion: Ex vivo 3D micro tumor testing using liquid and solid tissues is feasible for NSCLC patients with resected primary tumor or pleuritis carcinomatosa. Distinct patient sensitivity profiles for chemo-, targeted and immunotherapies were measured. A preliminary correlation of targeted therapy response with mutation status was found.
Discussion: The ex vivo 3D micro tumor testing platform is proven predictive for platinum-based therapy. The current study established the methods to accurately measure ex vivo NSCLC responses to all drug classes to correlate with clinical measures and further validate the platform for guiding treatment decisions.
Citation Format: Esmee Koedoot, Timothy J. Sijsenaar, Lieke J. Ceton, Dieudonné J. van der Meer, Thomas J. van Brakel, Peter van Zwam, Erica Geraedts, Willemijn Vader, Egbert F. Smit, Laurie C. Steinbusch, Christi M. Steendam. Ex vivo 3D micro tumor testing to assess chemotherapy and immunotherapy responses for NSCLC patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6396.