Morphological and functional analysis of the loading regimen with intravitreal ranibizumab in neovascular AMD

Abstract

Background: To quantify and correlate the morphological and functional effects of the recommended loading regimen with intravitreal ranibizumab in neovascular age-related macular degeneration (AMD).

Methods: In a prospective, interventional, clinical trial, 29 consecutive patients (29 eyes) with choroidal neovascularization (CNV) secondary to AMD received 3 initial monthly intravitreal injections of ranibizumab. During this loading regimen, best corrected visual acuity (BCVA) and microperimetry (MP) testing, as well as optical coherence tomography (OCT) and fluorescein angiography (FA) were performed using a standardized protocol and the results correlated.

Results: Significant morphological and functional therapeutic effects were observed as early as 1 week following the first treatment. Throughout the loading dose period, central retinal thickness (CRT) including intraretinal cysts and subretinal fluid decreased fast and significantly (p<0.01), PEDs resolved less rapidly. The mean leakage area by FA decreased (p<0.01) and retinal function (BCVA and MP) increased significantly (p<0.01 respectively). However, the change in morphology and function was only significant between baseline and week 1. There was no significant additional morphological or functional benefit following the second and third injection.

Conclusion: The initial administration of intravitreal ranibizumab in neovascular AMD induces a significant effect on intra- and subretinal fluid and visual function, subsequent injections have a less pronounced effect. It remains to be determined whether this loading regimen is mandatory in all patients or if a single dose regimen could lead to a comparable functional and morphological retinal improvement.