Safe immunosuppression-resistant pan-cancer immunotherapeutics by velcro-like density-dependent targeting of tumor-associated carbohydrate antigens

Bispecific antibodies and chimeric antigen receptor T cells are some of the most potent cancer immunotherapeutics in clinical use, yet most cancers remain poorly targetable. High-affinity antibodies required to maximize killing detect low antigen expression in normal tissue, risking "on-target, off-cancer" toxicity. This compels identification of cancer-restricted cell-surface protein antigens, which are rare. Tumor-associated carbohydrate antigens (TACAs) are the most abundant and widespread cancer antigens known but are poorly targetable by antibodies. Here, we describe glycan-dependent T cell recruiter (GlyTR) pan-cancer immunotherapeutics that utilize high-avidity "velcro-like" lectin binding to kill cells with high but not low TACA expression. GlyTR1 and GlyTR2 bind immunosuppressive β1,6GlcNAc-branched N-glycans or multiple TACAs (Tn, sialyl-Tn, LacDiNAc, and GD2), respectively, overcome immunosuppressive mechanisms in the tumor microenvironment and trigger target-density-dependent T cell-mediated pan-cancer killing, yet they lack toxicity in mice with human-like TACA expression. Density-dependent lectin binding to TACAs provides highly potent and safe pan-cancer immunotherapeutics.