VEGF receptors + PDGF receptors

Class

Pan-VEGFR/PDGFR tyrosine kinase inhibitor (axitinib), sustained-release intravitreal implant

Vascular endothelial growth factor (VEGF) receptors and platelet-derived growth factor (PDGF) receptors are cell-surface tyrosine kinases that drive the growth and stabilization of blood vessels. In several retinal diseases, notably neovascular age-related macular degeneration and diabetic macular edema, excessive VEGF signaling causes abnormal, leaky blood vessels to grow beneath or within the retina, leading to fluid accumulation, hemorrhage, and vision loss. Blocking VEGF receptor signaling is a well-established approach to controlling this process. PDGF receptors act on pericytes and mural cells that wrap around new vessels, providing structural support and resistance to anti-VEGF therapy alone; inhibiting both pathways together can more thoroughly suppress pathological vessel growth than targeting VEGF alone. A pan-VEGFR/PDGFR tyrosine kinase inhibitor blocks the intracellular enzymatic activity shared by these receptor families, interrupting downstream signaling regardless of which growth factor initiated it. Delivering such a small molecule through a sustained-release implant placed inside the eye is intended to maintain local drug exposure over an extended period, reducing reliance on frequent intraocular injections that are otherwise needed to sustain anti-VEGF effects. This mechanism is broadly relevant wherever chronic ocular neovascularization and vascular permeability underlie disease progression.