Intravitreal injection of vascular endothelial growth factor small interfering RNA inhibits growth and leakage in a nonhuman primate, laser-induced model of choroidal neovascularization.

PURPOSE: To determine the safety and efficacy of small interfering RNA (siRNA) directed against vascular endothelial growth factor (VEGF) in a nonhuman primate model of laser-induced choroidal neovascularization (CNV).

METHODS: Each animal received laser rupture of Bruch's membrane to induce CNV in both eyes. Each animal was then randomized to receive 0.05 mL of either vehicle alone or VEGF siRNA at 70 microg, 150 microg, or 350 microg in both eyes by intravitreal injection. Eyes were monitored weekly by ophthalmic examination, color photography, and fluorescein angiography for 36 days after laser injury. Electroretinograms were measured at baseline and at 5 weeks after laser. CNV on fluorescein angiograms were measured for area and graded for clinically significant leakage in a standardized, randomized, and double-masked fashion on days 15, 22, 29, and 36 after laser.

RESULTS: VEGF siRNA did not cause any change in electroretinographic, hemorrhage, inflammation, or clinical signs of toxicity. A single administration of VEGF siRNA significantly inhibited growth of CNV and attenuated angiographic leakage in a dose-dependent manner.

CONCLUSION: Intravitreal injection of VEGF siRNA is capable of inhibiting the growth and vascular permeability of laser-induced CNV in a nonhuman primate in a dose-dependent manner. This study demonstrates preclinical proof of a principle that supports proceeding to clinical studies of VEGF siRNA in patients with exudative age-related macular degeneration.