Clinical outcomes of switching to aflibercept using a pro re nata treatment regimen in patients with neovascular age-related macular degeneration who incompletely responded to ranibizumab

BACKGROUND: To assess the effect of switching patients previously incompletely treated with ranibizumab (RBZ) to aflibercept (AFL) using a pro re nata (PRN) treatment strategy in neovascular age-related macular degeneration (nvAMD). METHODS: A retrospective case series was conducted on patients who had persistent or recurrent intra- and/or sub-retinal fluid treated initially with RBZ and subsequently switched to AFL. The main outcome measures were best corrected visual acuity (BCVA) and central retinal thickness (CRT) measured at different stages of the study. Friedman analysis of variance and Wilcoxon test were used to examine differences in BCVA and CRT. RESULTS: Two hundred and seven eyes from 182 patients were included. BCVA and CRT improved significantly initially following 3 RBZ injections with a mean gain of 3.7 letters (p < 0.001) and a mean loss of 69 μm (p < 0.001) respectively. Following PRN RBZ therapy and immediately prior to switching to AFL (mean 129 weeks), there was a mean loss of 6.7 letters (p < 0.001) BCVA and a mean gain of 24 μm (p < 0.001) CRT. AFL loading resulted in a mean improvement of 0.7 letters (p = 0.28) BCVA and 55 μm (p < 0.001) CRT. At final follow-up following AFL PRN therapy (mean 85 weeks), there was a mean loss of 8.9 letters (p < 0.001) BCVA and a mean gain of 12 μm (p < 0.05) CRT. CONCLUSION: AFL loading resulted in a significant anatomical improvement but no significant change in visual acuity. However, the benefits of switching were gradually lost over time with AFL PRN dosing despite an increased injection rate when compared with RBZ PRN treatment. TRIAL REGISTRATION: Not applicable ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s12886-018-0688-3) contains supplementary material, which is available to authorized users.