Abstract 4724: Evaluating immunotherapy and combination therapy efficacy in kidney cancer using a multicellular 3D immune-microtumor model

Advanced renal cell carcinoma (RCC) presents a significant treatment challenge, as response rates to immunotherapies, receptor-tyrosine kinase inhibitors (TKIs) and combination therapies remain unpredictable. A functional precision medicine approach that models tumor-immune interactions can help tailor patient-specific therapy selection, reducing ineffective treatment cycles. Pear Bio’s 3D immune-microtumor platform recreates the RCC tumor immune microenvironment (TiME), retaining relevant cell subpopulations to evaluate drug efficacy. Using fresh RCC tumor tissues and matched blood, the Pear Bio platform generates immune-microtumor cultures within a custom hydrogel optimized to sustain tumor, immune, and stromal cells (N=20). Tumor cells are co-cultured with activated peripheral blood mononuclear cells (PBMCs), with CD8+ T cells and CD8- PBMCs tracked via fluorescent dyes. FDA-approved RCC therapies, including immunotherapies (e.g. ipilimumab, nivolumab, pembrolizumab) and TKIs (e.g. axitinib, lenvatinib), are administered as monotherapies or in combination. Over 4 days, 3D confocal imaging assesses functional metrics including immune cell infiltration and tumor cell death, quantified through a proprietary computer vision pipeline. Immunofluorescence (IF) of 3D immune-microtumors (N=20) demonstrated retention of diverse TiME cell types—including tumor, endothelial, epithelial, immune, and cancer-associated fibroblasts—at day 0 and day 4 of culture. RNAseq confirmed transcriptional similarity of cells pre- and post-culture, with cell deconvolution further supporting immune compartment retention. Therapy dosing was optimized through molecular assays (IF, Luminex, flow cytometry, in-cell western) and functional screens on immune-microtumors (N=45). Post optimization, 3D immune-microtumors were used to test clinical treatment regimens and assess combo therapy responses in RCC in our trial (PEAR-TREE N=20 ISRCTN10001405). Pembrolizumab monotherapy increased PBMC and CD8+ cell infiltration by 26% and 14%, respectively, and boosted tumor cell death by 15% compared to controls (N=5). When combined with lenvatinib or axitinib, pembrolizumab further reduced tumor cell viability by 10% and 19%, respectively. This functional analysis reveals intra-patient response variability, underscoring the immune-microtumor model’s potential to capture personalized RCC responses to combination therapies. This 3D immune-microtumor model allows for precise ex vivo testing of combination therapies in RCC, capturing patient-specific interactions within a functional TiME. Current clinical validation in the PEAR-TREE2 RCC trial (NCT06264479) aims to further correlate ex vivo findings with in vivo outcomes, holding promise to guide optimized, personalized RCC treatment. Citation Format: Eleonora Peerani, Keqian Nan, Jonathan Ient, Polina Maximchik, Nourdine K. Bah, Jay Kearney, Jessica A. Hudson, Roseanna K. Hare, Farah Sangkolah, George R. de Fraine, Kerrie L. Loughrey, Elli Tham, Francesco Iori, Matthew H. Williams, Maxine G. Tran, Duleek N. Ranatunga. Evaluating immunotherapy and combination therapy efficacy in kidney cancer using a multicellular 3D immune-microtumor model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 4724.