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

Objectives: 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. Design: Nonrandomized, prospective, clinical study. Participants: Forty-seven eyes of 47 patients with exudative AMD undergoing intravitreal ranibizumab injections. Methods: 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). Main Outcome Measures: Intraocular VEGF concentration, recurrence of CNV activity shown by SD-OCT, and vision loss. Results: 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). Conclusions: 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.