9E3-PBD

9E3-PBD is a preclinical-stage antibody-drug conjugate (ADC) targeting the adhesion G protein-coupled receptor G1 (ADGRG1/GPR56). It consists of the non-agonist monoclonal antibody 9E3 site-specifically conjugated to a potent pyrrolobenzodiazepine (PBD) DNA-alkylating payload. GPR56 is highly expressed in triple-negative breast cancer (TNBC) and is associated with poor prognosis and the activation of the FAK-SRC survival pathway. Upon binding to GPR56, the ADC is internalized and trafficked to lysosomes, where the PBD payload is released to induce DNA damage and cell death. Developed by researchers at UTHealth Houston and Baylor College of Medicine, 9E3-PBD is being investigated for its potential to provide a more selective and safer therapeutic option for TNBC compared to existing therapies like sacituzumab govitecan.