Targeting cancer-associated glycosylation for adoptive T cell therapy of gastro-intestinal and gynecological cancers

CAR T cell therapy has provided a significant improvement for patients with chemotherapy-resistant B cell malignancies. However, CAR T cell treatment of patients with solid cancers has been more difficult, in part because of the heterogeneous expression of tumor-specific cell surface antigens. Here, we describe the generation of a fully human CAR targeting altered glycosylation in secretory epithelial cancers. The expression of the target antigen, the truncated, sialylated O-glycan sialyl-Thomsen-Nouveau antigen (STn), was studied with a highly STn-specific antibody across various different tumor tissues. Strong expression was found in a high proportion of gastro-intestinal cancers including pancreatic cancers and in gynecological cancers, in particular ovarian and endometrial tumors. T cells expressing anti-STn CAR were tested in vitro and in vivo. Anti-STn CAR T cells showed activity in mouse models as well as in assays with primary ovarian cancer samples. No significant toxicity was observed in mouse models, although some intraluminal expression of STn was found in gastro-intestinal mouse tissue. Taken together, this fully human anti-STn CAR construct shows promising activity in preclinical tumor models supporting its further evaluation in early clinical trials.