Definition

An antagonist of the immune checkpoint endothelin B receptor (ETBR; EDNRB), with potential immunomodulating and antineoplastic activities. Upon administration, the ETBR blocker ENB 003 selectively targets and binds to ETBR expressed on tumor cells. This prevents ETBR-mediated signaling and may abrogate the immunosuppressive tumor microenvironment (TME), may enhance a T-cell mediated anti-tumor immune response and may inhibit proliferation of ETBR-expressing tumor cells. ETBR, a G-protein coupled receptor, is overexpressed in a variety of tumor cell types and plays a key role in tumor cell proliferation, invasion, epithelial-mesenchymal transition (EMT) and angiogenesis. It also plays a role in tumor immunosuppression and blocks T-cell trafficking.