Site-specifically labeled CA19.9-targeted immunoconjugates for the PET, NIRF, and multimodal PET/NIRF imaging of pancreatic cancer

Significance Pancreatic cancer will soon be the second leading cause of cancer deaths annually, yet no adequate molecular imaging tools exist to aid in the staging, monitoring, and treatment of the disease. Here we describe the development and preclinical evaluation of three unique immunoconjugates for positron emission tomography, near-infrared fluorescent optical imaging, and multimodal imaging of pancreatic ductal adenocarcinoma (PDAC). The probes were developed using a site-specific, chemoenzymatic methodology that is robust, reproducible, and modular. By targeting CA19.9, the most abundant antigen in >90% of PDAC tumors, we were able to obtain high-quality images in multiple murine models of PDAC, suggesting these constructs could be the core of a molecular imaging toolkit aimed at improving outcomes for patients with PDAC.