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

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.

CONCLUSION: 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.