Abstract LB028: A Man9xPS CAR T cell immunotherapy demonstrates robust preclinical safety and efficacy in an orthotopic pancreatic cancer model

Abstract Aberrant expression of high-mannose glycans (Man9) and phosphatidylserine (PS) lipids on tumor cells represents a promising immunotherapeutic target for cancer. Previously, we demonstrated that a Man9xPS targeting T cell engager molecule significantly improved tumor control and survival in acute myeloid leukemia (AML) mouse models. Building on these findings, we now report the development of a Man9xPS CAR T cell therapy designed to enhance tumor targeting specificity and overcome the challenges seen with protein-antigen escape and mutational background. Methods: Man9xPS CAR T cells (VCAR300) were engineered to target high-mannose glycans and PS lipids enriched on the outer leaflet of cancer cell membranes. Binding specificity was assessed using glycan array analysis, flow cytometry, and immunohistochemistry (IHC) of human tumor and normal tissue sections. Functional efficacy of Man9xPS CAR T cells was evaluated via in vitro cytotoxicity assays against several solid tumor cell lines, including breast cancer MDA-MB-231, lung cancer NCI-H460, and liver cancer Hep3B. Pancreatic cancer targeting was validated using human pancreatic cell lines PANC-1, Capan-2 and AsPC-1. In vivo therapeutic potential was assessed using bioluminescence in a syngeneic, orthotopic pancreatic cancer mouse model (PANC02-Luc), implanted in the pancreas tail of female C57BL/6 mice. Ongoing studies are evaluating tumor growth inhibition and survival outcomes. Results: Man9xPS CAR T cells demonstrated high in vitro specificity for pancreatic tumors and pancreatic cancer stem cells, with no binding to normal pancreatic cells or stem cells. IHC confirmed robust expression of these targets on pancreatic cancer tissues, with minimal detection in healthy tissues. In vitro killing assays revealed potent cytotoxic activity of Man9xPS CAR T cells against several solid tumor cell lines, achieving significant target cell lysis at low effector-to-target ratios. Preliminary in vivo data from the pancreatic cancer syngeneic model show promising tumor control, with detailed survival analyses currently underway. Conclusions: Man9xPS CAR T cell therapy exhibits strong preclinical efficacy and specificity in targeting tumors characterized by aberrant high-mannose glycans and PS lipids. These findings support the potential of Man9xPS CAR T cells as a novel immunotherapy for pancreatic cancer, a challenging disease with known antigen escape mechanisms and genetic heterogeneity. Ongoing studies will further elucidate their therapeutic potential and safety, paving the way for clinical translation. This abstract was reviewed and edited with the assistance of artificial intelligence (AI) tools to enhance clarity, grammar, and overall readability. Citation Format: Shabnam Samimi, Ashley Varkey, Manpreet Bariana, Elena Cassella, Sonia Sequeira, Johannes Zakrzewski, Mahiuddin Ahmed. A Man9xPS CAR T cell immunotherapy demonstrates robust preclinical safety and efficacy in an orthotopic pancreatic cancer model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_2):Abstract nr LB028.