Vascular Endothelial Growth Factor in Patients with Exudative Age-related Macular Degeneration Treated with Ranibizumab

Abstract

To analyze the temporal correlations of vascular endothelial growth factor (VEGF) suppression, morphologic recurrence of choroidal neovascularization (CNV), and visual acuity loss in eyes with exudative age-related macular degeneration (AMD) treated with ranibizumab. Nonrandomized, prospective, clinical study. Forty-seven eyes of 47 patients with exudative AMD undergoing intravitreal ranibizumab injections. Aqueous humor specimens were taken before each intravitreal ranibizumab injection. Visual acuity testing, spectral domain optical coherence tomography (SD-OCT), and fundoscopy were performed before each injection. Vascular endothelial growth factor A was measured by Luminex multiplex bead analysis (Luminex Inc., Austin, TX). Intraocular VEGF concentration, recurrence of CNV activity shown by SD-OCT, and vision loss. Ranibizumab resulted in complete VEGF suppression within a mean period of 37.8 days (standard deviation [SD] ± 4.8 days; range, 26-49 days). Recurrences of CNV activity as determined by SD-OCT occurred 93.7 days (SD ± 69.9 days; range, 57-368 days) after the last ranibizumab treatment. The VEGF levels were never suppressed when a recurrence occurred. Functional recurrence (visual acuity) occurred 114.3 days (SD ± 81.4 days; range, 57-398 days) after previous treatment. The VEGF levels did not differ significantly between baseline and recurrence (69.3 pg/ml vs. 74.14 pg/ml; 95% confidence interval, -18.87 to 9.12). A monthly intravitreal injection of 0.5 mg ranibizumab yields a durable VEGF inhibition. The recurrences of CNV as determined by SD-OCT are always preceded by a loss of intraocular VEGF suppression and usually followed by loss of visual acuity in the further course.