Abstract 5896: Platform approach to develop antibodies specifically recognizing cancer-associated glycoforms

Abstract Introduction: Recent advances in antibody engineering have created a portfolio of highly potent therapeutic approaches like antibody-drug conjugates (ADCs), radioimmunoconjugates (RITs), chimeric antigen receptors (CARs) or bi-specifics. Due to the increased potency, these drugs are more than ever dependent on very clean targets to prevent side effects. We aim to address this major problem through our approach to develop antibodies with improved tumor specificity and reduced on-target/off-tumor binding utilizing the aberrant O-glycosylation on tumor cells. Altered glycosylation of proteins and lipids is one of the most drastic changes in cancer, giving rise to truncated or highly fucosylated and highly sialylated glycans which are almost absent on normal cells. Thus, developing antibodies against protein/carbohydrate combined epitopes (GlycoTargets) comprising these tumor-specific glycans enables highly potent therapies with reduced off-tumor toxicity. Experimental procedures: A workflow and corresponding database was established to evaluate the O-glycosylation of proteins. The first and most basic criterion is the presence of suitable O-glycosylated peptide stretches in the extracellular domain of a protein based on predictions. For proteins fulfilling this criterion cancer-relevant expression is analyzed in a second step. This is done either using publicly available data or experimentally (immunohistochemistry or protein expression data). During the final major step, the theoretical existence of suitable O-glycosylation is confirmed by our own experimental data. This includes analysis of cellularly expressed proteins by anti-glycan antibodies and mass spectrometric studies. Results summary: Case studies will be presented that highlight our workflow to identify suitable GlycoTargets based on publicly available data analysis and experimental confirmation. Additionally, the subsequent development of antibodies against the identified GlycoTargets will be shown. Conclusion: A standardized process was developed for the data collection and prioritization of potential GlycoTargets. The obtained information is subsequently used for targeted discovery of antibodies that bind to protein/carbohydrate combined glycoepitopes (GlycoTargets) offering increased tumor-specificity compared to simple protein targets. Citation Format: Patrik Kehler, Johanna Gellert, Lisa Kalfhues, Sophie Marinoff, Manon Weis, Andreas Franz, Naomi Kast, Stephanie Gurka, Marianne Morche, Evelyn Hartung, Timo Lischke, Sarah Mayer-Hain, Antje Danielczyk. Platform approach to develop antibodies specifically recognizing cancer-associated glycoforms 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 (6Suppl): Abstract nr 5896.