A prospective study on intravitreal bevacizumab (Avastin®) for neovascular age-related macular degeneration of different durations

Abstract

Purpose: Choroidal neovascularization (CNV) accounts for 85-90% of severe visual impairment in age-related macular degeneration (AMD). Vascular endothelial growth factor (VEGF) is a major factor mediating angiogenesis, and VEGF inhibitors have become a new treatment modality. In this prospective study, we used bevacizumab (Avastin®), a recombinant monoclonal antibody to VEGF, to treat neovascular AMD. Methods: The case material comprised 36 subjects (26 females, 10 males) aged 65-88 years with subfoveal neovascular AMD with all subtypes of CNV. There were two categories of patients: category I, long-standing CNV (12 months or more), preoperative visual acuity (VA) 0.16 (mean); category II, CNV (duration <12 months), preoperative VA 0.25 (mean). Evaluation protocol included the Early Treatment Diabetic Retinopathy Study (ETDRS) VA, clinical ophthalmological examination, fluorescein angiography and optical coherence tomography (OCT). Intravitreal injections of bevacizumab (Avastin®) (IVB), 1.25 mg (0.05 ml), were given under an operating microscope and aseptic conditions in a theatre for surgery with intervals of 4 or 6 weeks during the first 3 months and subsequently according to clinical assessment. The follow-up was 6 months in all cases. Results: At 6 months, mean VA had improved by 4.6 ETDRS letters in the entire case material (P = 0.001), by 3.9 letters in category I (duration 12 months or more) and by 6.0 letters in category II (duration <12 months). A total of 148 IVB (mean 4.1 injections/eye) were delivered during 6 months, the first 3 months comprising 3.1 IVB (mean) and the last 3 months 1.0 IVB (mean). No eyes suffered visual decline of 15 ETDRS letters. Fluorescein angiograms displayed stabilization or regression of CNV activity; OCT showed resorption of intraretinal oedema and subretinal fluid. No severe complications occurred but recurrence was common, and repeated IVBs were necessary in most cases during the 6-month period. Conclusions: When addressing the issue of frequency of IBV, we observed that 6-week intervals were sufficient because VA and CNV lesions generally stabilized at 4 weeks. The gain in VA was promising in eyes with < 12 months CNV duration. Even in eyes with a longer CNV duration, a slight visual improvement was observed when retinal oedema resorbed, although subretinal fibrosis and general cellular damage certainly limited recovery. © Journal compilation © 2008 Acta Ophthalmol.