Abstract IA009: Antibody-lectin chimeras for glyco-immune checkpoint blockade

Abstract

Abstract Despite the curative potential of checkpoint blockade immunotherapy, a majority of patients remain unresponsive to existing treatments. Glyco-immune checkpoints – interactions of cell-surface glycans with lectin, or glycan binding, immunoreceptors – have emerged as prominent mechanisms of immune evasion and therapeutic resistance in cancer. Here, we describe antibody-lectin chimeras (AbLecs), a modular platform for glyco-immune checkpoint blockade. AbLecs are bispecific antibody-like molecules comprising a tumor-targeting arm as well as a lectin “decoy receptor” domain that directly binds tumor glycans and blocks their ability to engage lectin receptors on immune cells. AbLecs enhanced cancer cell killing in vitro via macrophage phagocytosis and NK cell and granulocyte cytotoxicity compared to their parent monoclonal antibodies. AbLec treatment reduced tumor burden in vivo compared to treatment with the parent antibody in a humanized model of metastatic HER2+ cancer. Furthermore, AbLecs synergized with blockade of the “don’t eat me” signal CD47 for enhanced tumor killing. AbLecs can be readily designed to target numerous tumor-associated antigens and glyco-immune checkpoint ligands, and therefore represent a new modality of cancer immunotherapy. Citation Format: Jessica Stark. Antibody-lectin chimeras for glyco-immune checkpoint blockade [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr IA009.