YB-800

YB-800 is a fully humanized, first-in-class monoclonal antibody targeting the neuronal pentraxin receptor (NPTXR), a type II transmembrane trans-synaptic organizer that is minimally expressed in normal tissues but overexpressed across multiple gastrointestinal and other solid tumors.[1][3][5][8] By binding NPTXR on tumor cells, YB-800 selectively recognizes and internalizes into cancer cells, enabling its use as a platform for antibody-drug conjugates and radiopharmaceuticals with established payloads and third-generation linkers, and it has demonstrated anti-tumor activity in vitro and in vivo in models of colorectal, gastric, esophageal, hepatocellular, pancreatic, bladder, breast, and thyroid cancers.[1][3][5][7][8] The antibody is being developed by Ymmunobio (Ymmunobio Therapeutics/Ymmunobio AG) as a novel targeted therapy for solid tumors, initially focusing on gastro-intestinal cancers, with ongoing preclinical development and plans for IND-enabling studies.[2][3][5][7][8]