Bispecific receptor decoy proteins block ocular neovascularization via simultaneous blockade of vascular endothelial growth factor A and C.

Abstract

Several debilitating eye diseases that lead to vision loss are driven by ocular neovascularization, which entails abnormal blood vessel growth in the eye. Neovascularization is often induced by the upregulation of vascular endothelial growth factor (VEGF) ligands, which activate angiogenesis through engagement of VEGF receptor (VEGFR) proteins on endothelial cells. Therapeutic interventions that block ocular neovascularization by targeting VEGF ligands, particularly VEGF-A, have revolutionized eye disease treatment. However, a significant population of patients are either non-responders or develop resistance, which can be driven by the upregulation of other VEGF family ligands such as VEGF-C. Here, we engineered two bispecific receptor decoy fusion proteins that incorporate domains of VEGFR-1 and VEGFR-2 for more effective and comprehensive inhibition of VEGF ligands. We demonstrated that our engineered proteins bind all VEGF ligands and can sequester two ligands simultaneously. We further showed that these molecules block VEGF activity to potently inhibit proliferation, migration, and survival of human endothelial cells. Moreover, these receptor decoy proteins significantly reduced ocular neovascularization in two mouse models at doses wherein the current standard-of-care anti-VEGF therapy is ineffective. Collectively, our engineered receptor decoy proteins present a new architecture for VEGF pathway inhibition, offering a promising treatment paradigm for ocular diseases.