OMTX703

OMTX703 is a preclinical antibody-drug conjugate (ADC) developed by Oncomatryx Biopharma that targets endoglin (ENG, CD105), a transmembrane glycoprotein overexpressed on tumor endothelial cells and in some tumor types, particularly Ewing sarcoma. It consists of an anti-endoglin monoclonal antibody (based on the OMTX003 antibody) conjugated to a potent cytolysin payload, leading to internalization upon ENG binding and subsequent tumor cell death via delivery of the cytotoxic agent.[1][4][5][7] In preclinical models of Ewing sarcoma and uveal melanoma, OMTX703 selectively inhibited proliferation of ENG-expressing cells and produced marked, dose-dependent tumor growth delay and regression, demonstrating first-in-class anti-ENG ADC activity as a strategy to eradicate Ewing sarcoma and other ENG-positive malignancies.[1][4][5][6]