OBJECTIVE:

To evaluate the safety and efficacy of intravitreal injections of an antigen-binding fragment of a recombinant humanized monoclonal antibody directed toward vascular endothelial growth factor (rhuFab VEGF) in a monkey model of choroidal neovascularization (CNV).

METHODS:

In phase 1 of the study, each animal received intravitreal injections, 500 microg per eye, of rhuFab VEGF in one eye (prevention eye), while the contralateral eye received rhuFab VEGF vehicle (control eye) at 2-week intervals. On day 21, laser photocoagulation was performed to induce CNV. In phase 2, the vehicle-treated eye was crossed over and both eyes received 500 microg of rhuFab VEGF beginning 21 days following laser-induced injury at days 42 and 56. The eyes were monitored by ophthalmic examinations, color photographs, and fluorescein angiography.

RESULTS:

rhuFab VEGF did not cause any ocular hemorrhages. All eyes treated with rhuFab VEGF developed acute anterior chamber inflammation within 24 hours of the first injection that resolved within 1 week, and this inflammation was less severe with subsequent injections. The incidence of CNV, defined angiographically, was significantly lower in the prevention eyes than the control eyes (P<.001). Subsequent treatments were associated with less leakage in eyes with established CNV that were crossed over from the control eyes to the treatment eyes (P =.001).

CONCLUSIONS:

Intravitreal rhuFab VEGF injections prevented formation of clinically significant CNV in cynomolgus monkeys and decreased leakage of already formed CNV with no significant toxic effects.

CLINICAL RELEVANCE:

This study provides the nonclinical proof of principle for ongoing clinical studies of intravitreally injected rhuFab VEGF in patients with neovascular age-related macular degeneration.