The CA19-9 glycan is a viable target for CAR T cell therapy in pancreatic and other solid tumors.

BACKGROUND & AIMS: Chimeric antigen receptor (CAR) T cell therapy for pancreatic ductal adenocarcinoma (PDAC) has been challenging, in part due to the paucity of tumor-specific cell-surface targets. Here, we explored the design feasibility and anti-tumor efficacy of CAR T cells recognizing the CA19-9 glycan, a tumor antigen commonly associated with PDAC and other gastrointestinal tumors. METHODS: We designed and screened 14 CA19-9 CAR constructs harboring different single-chain variable fragments (scFvs) and intracellular signaling domains. After narrowing down to one optimal CAR configuration, we further evaluated its anti-tumor efficacy in various in vitro and in vivo models. RESULTS: Out of 14 CAR constructs tested, we identified one design - AbLIFT15.28z - that enabled robust T cell expansion and efficient tumor cell-killing properties. Experiments with human PDAC cell lines and patient-derived organoids (PDOs) revealed that AbLIFT15.28z CAR T cell-mediated cytotoxicity was confined to cancer cells expressing CA19-9, both in vitro and in vivo. We then tested the efficacy of AbLIFT15.28z CAR T cells in immunocompetent murine models of PDAC, revealing significant effects against both primary and metastatic tumors. Efficacy was not limited to PDAC, as robust and specific anti-tumor effects were observed against CA19-9-expressing tumors of the colon, stomach, esophagus, and biliary tract. CONCLUSIONS: Our findings demonstrate the effectiveness of CA19-9 CAR T cells in GI cancers using various pre-clinical tumor models, providing a rationale for further clinical development.