The potent small molecule integrin antagonist THR-687 is a promising next-generation therapy for retinal vascular disorders

Integrins are associated with various eye diseases such as diabetic retinopathy (DR) and wet age-related macular degeneration (AMD) and implicated in main pathologic disease hallmarks like neovascularization, inflammation, fibrosis and vascular leakage. Targeting integrins has the potential to attenuate these vision-threatening processes, independent of anti-vascular endothelial growth factor (VEGF) responsiveness. The current investigation characterized THR-687 as a novel pan RGD (arginylglycylaspartic acid) integrin receptor antagonist able to compete for binding with the natural ligand with nanomolar potency (e.g. alpha(v)beta(3) (IC50 of 4.4 +/- 2.7 nM), alpha(v)beta(5) (IC50 of 1.3 +/- 0.5 nM) and alpha(5)beta(1) (IC50 of 6.8 +/- 3.2 nM)). THR-687 prevented the migration of human umbilical vein endothelial cells (HUVECs) into a cell-free area (IC50 of 258 +/- 113 nM) as well as vessel sprouting in an ex vivo mouse choroidal explant model (IC50 of 236 +/- 173 nM), and was able to induce the regression of pre-existing vascular sprouts. Moreover, combined intravitreal and intraperitoneal administration of THR-687 potently inhibited VEGF-induced leakage in the mouse retina. In addition, THR-687 injected intravitreally at 3 different dose levels (0.45 mg, 2.25 mg or 4.5 mg/eye) potently inhibited neovascularization-induced leakage in the cynomolgus laser-induced choroidal neovascularization (CNV) model. These data suggest that THR-687 is a promising drug candidate for the treatment of vision-threatening retinal vascular eye diseases such as DR and wet AMD.