Inhibition of Corneal Neovascularization by Topical Bevacizumab (Anti-VEGF) and Sunitinib (Anti-VEGF and Anti-PDGF) in an Animal Model JUAN J. PÉREZ-SANTONJA, EZEQUIEL CAMPOS-MOLLO, MARIOLA LLEDÓ-RIQUELME, JAIME JAVALOY, AND JORGE L. ALIÓ ● PURPOSE: To evaluate the effects of topically applied bevacizumab and sunitinib on experimentally induced corneal neovascularization. ● DESIGN: Experimental animal study. ● METHODS: Thirty-six New Zealand rabbits were in- volved. One eye per rabbit was used. Corneal neovascu- larization was induced by placing 5 silk sutures in the upper cornea. Rabbits were randomized to 1 of 3 groups (12 rabbits each): Group 1 received saline 0.9%, Group 2 bevacizumab 5 mg/mL, and Group 3 sunitinib 0.5 mg/mL. All treatments were administered 3 times daily for 14 days. Photographs were taken on a slit lamp on days 7 and 14, and angiographic photographs were taken on day 14. The area of neovascularization was measured in mm 2 , percentage of the total corneal area, and percent- age of the corneal surface covered by sutures. ● RESULTS: On day 14, corneal neovascularization area in Group 1 (25.92  5.08 mm 2 , 18.78%  3.5% of corneal surface, 105.59%  18.9% of corneal surface with sutures) was larger than in Groups 2 (18.52  7.94 mm 2 , 13.67%  5.8%, 76.35%  33.2%) (1-way analysis of variance, P  .041) and 3 (4.57  2.32 mm 2 , 3.40%  1.7%, 18.94%  9.2%)(P < .001). Neovas- cularization in Group 2 was larger than in Group 3 (P < .001). Compared to saline, corneal neovascularization was inhibited 28.5% by bevacizumab and 82.3% by sunitinib. Sunitinib settled on the iris. ● CONCLUSIONS: Topical administration of both bevaci- zumab and sunitinib inhibits corneal neovascularization in rabbits. But vascular endothelial growth factor (VEGF) pathway blockade by bevacizumab was not sufficient for a profound inhibition. Blocking both VEGF and platelet- derived growth factor pathways using sunitinib was 3-fold more effective. (Am J Ophthalmol 2010;150:519 –528. © 2010 by Elsevier Inc. All rights reserved.) A NGIOGENESIS IS THE FORMATION OF NEW BLOOD vessels from preexisting vascular structures. 1 In the cornea, it is a not-infrequent consequence of var- ious inflammatory, infectious, and traumatic corneal dis- orders. 2 Corneal neovascularization, however, has the unwanted consequence of opacification of adjacent corneal tissue and thus can result in significant reduction in visual function. 1,3 Angiogenesis is a complex multistep process tightly regulated by the action of both stimulatory (angiogenic factors) and inhibitory (angiogenic inhibitors) molecules. 4 Vascular endothelial growth factor (VEGF) appears to be 1 of the most important regulators of corneal angiogene- sis. 5,6 Corneal epithelial and endothelial cells, vascular endothelial cells of limbal vessels, and fibroblasts and macrophages in scar tissue all have been found to excrete VEGF, especially in inflamed and vascularized corneas. 1,6 VEGF and its tyrosine kinase receptors VEGFR1 (flt-1) and, particularly, VEGFR2 (flk-1) promote many aspects of the angiogenic process. VEGF increases vascular perme- ability of venules and induces vascular endothelial cell mitosis and migration. 1,7 A second important regulator of angiogenesis is platelet- derived growth factor (PDGF). Newly formed vessels will regress spontaneously unless they are enveloped by peri- cytes, an event promoted by platelet-derived growth factor B (PDGFB). 8 Vascular endothelial cells produce PDGFB, and the surrounding mural cells (pericytes and vascular smooth muscle cells) express platelet-derived growth factor receptor type  (PDGF receptor type  or PDGFR). 9 Bevacizumab is a monoclonal antibody that binds to VEGF with high specificity, thereby blocking VEGF- mediated signaling pathways and thus angiogenesis. 10 Be- vacizumab, approved originally for the treatment of metastatic colorectal cancer, 11 has been used in ophthal- mology (off-label) for the treatment of exudative age- related macular degeneration, proliferative diabetic retinopathy, and iris rubeosis, with promising results. 12,13 Recently, topical and subconjunctival administration of bevacizumab has been reported in experimental models and in human clinical cases for inhibition or regression of corneal neovascularization. 14 –19 Corneal neovasculariza- tion was inhibited or regressed significantly in the above studies, although it was not completely eliminated. Accepted for publication Apr 18, 2010. From the Refractive Surgery and Cornea Unit, Alicante Institute of Ophthalmology/Vissum, Miguel Hernández University School of Medi- cine, Alicante, Spain (J.J.P.S., J.J., J.L.A.); the Department of Ophthal- mology, Virgen de los Lirios Hospital, Alcoy, Alicante, Spain (J.J.P.S., E.C.M.); and the Department of Ophthalmology, Elche University General Hospital, Elche, Alicante, Spain (M.L.R.). Inquiries to Juan J. Pérez-Santonja, Instituto Oftalmológico de Alicante/Vissum, Avda. Denia s/n, 03016-Alicante, Spain; e-mail: jjpsantonja@coma.es © 2010 BY ELSEVIER INC.ALL RIGHTS RESERVED. 0002-9394/$36.00 519 doi:10.1016/j.ajo.2010.04.024