A tetravalent bispecific protein enables targeted degradation of VCAM-1 and VEGFR for treatment of choroidal neovascularization

Wet age-related macular degeneration (AMD), a leading cause of irreversible vision loss, is driven by pathological choroidal neovascularization (CNV). Although anti-vascular endothelial growth factor (anti-VEGF) therapies remain the clinical standard, their utility is constrained by incomplete responses in nearly 50% of patients and off-target risks—such as geographic atrophy—stemming from non-specific VEGF blockade. Here, we identify a robust correlation between vascular cell adhesion molecule-1 (VCAM-1) and VEGF/VEGF receptor (VEGFR) expression in aqueous humor from AMD patients and in murine CNV models. Thus, we engineered a tetravalent bispecific protein, RHV, by functionalizing an L-rhamnulose-1-phosphate aldolase scaffold with peptides that selectively bind VCAM-1 and the VEGFR on neovessels. The tetravalent design confers high apparent affinity, enhancing pathological endothelial targeting while sparing healthy retinal vasculature. RHV induces concurrent internalization and lysosomal degradation of both VCAM-1 and VEGFR via a head-to-tail binding mode, leading to sustained inhibition of the VEGF/VEGFR, PI3K/AKT and Apelin/APJ signaling pathways. In murine CNV models, a single intravitreal injection of RHV exhibits superior ocular retention and lesion penetration, achieving therapeutic efficacy comparable to aflibercept [a ligand-trap fusion protein for VEGF-A, VEGF-B and placental growth factor (PIGF)] at one-quarter of the molar dose. This dual-receptor degradation-based strategy represents a targeted and durable approach for treating ocular neovascularization.