Anti-VEGF-refractory Exudative Age-related Macular Degeneration: Differential Response According to Features on Optical Coherence Tomography

Purpose: To describe optical coherence tomography (OCT) characteristics of neovascular age-related macular degeneration (AMD) patients refractory to intravitreal anti-vascular endothelial growth factor (VEGF) injections (ranibizumab, bevacizumab) and their responses to alternative anti-VEGF agents or photodynamic therapy (PDT). Methods: A retrospective review of 267 neovascular AMD patients treated with intravitreal anti-VEGF injections. Results: Twenty patients (7.5%) were refractory to anti-VEGF injections (stationary or increased retinal exudation despite three or more monthly injections). They were grouped into either the extensive intraretinal fluid group (IRF group, 9 patients) or the subretinal fluid only group (SRF group, 11 patients) according to OCT findings. In the IRF group, response rates to subsequent treatment were 0% (0 / 7) for bevacizumab, 50% (3 / 6) for ranibizumab and 50% (3 / 6) for PDT ± anti-VEGF. Three out of four bevacizumab-refractory patients showed response to ranibizumab as a secondary treatment. In the SRF group, response rates were lower with 0% (0 / 7) for bevacizumab, 22.2% (2 / 9) for ranibizumab and 28.6% (2 / 7) for PDT ± anti-VEGF. One out of four bevacizumab-refractory patients responded to ranibizumab. The visual outcome was worse in the IRF group (median 20 / 1,000) than in the SRF group (median 20 / 100). Conclusions: In anti-VEGF-refractory neovascular AMD, patients with extensive IRF refractory to bevacizumab can be responsive to ranibizumab while patients with SRF may be refractory to both, suggesting a different pathophysiology and intraocular pharmacokinetics.