Abstract
Purpose: :
Vascular endothelial growth factor (VEGF) has been shown to be neuroprotective. While many patients are currently receiving multiple injections of anti-VEGF medications for age-related macular degeneration (AMD), retinal health as measured by electroretinography (ERG) has been ignored in clinical trials. We sought to determine if chronic VEGF inhibition would be toxic to the retina by utilizing pattern electroretinography (PERG) in patients with neovascular AMD receiving monthly injections of ranibizumab.
Methods: :
This is an open-label, single arm study of intravitreally administered ranibizumab in on-label treatment of naïve patients followed by an assessment of retinal function using PERG. Seventeen patients received monthly injections of ranibizumab for 6 months. Baseline visual acuity (VA), optical coherence tomography (OCT), and fluorescein angiography were obtained. PERG was performed prior to and at 1 month, 3 months, and 6 months after first treatment. PERGs were interpreted by a trained reader masked to the clinical data.
Results: :
The mean patient age was 79.6 (range 69 - 90 years). There was an equal distribution of CNV lesion type (47% classic and 53% occult). Fluid resolution by OCT was observed in 76% of patients. Mean VA prior to treatment was 20/85 with improvement to a mean of 20/55 (p = .004) at 6 months. At baseline, mean P50 and N95 amplitudes were 1.3 + 0.69 µV and 1.5 + 0.71 µV respectively. At 3 months, P50 tracings improved from pre-injection values (1.7 + 0.85 µV p=.049) however these gains were not sustained. At 6 months after initial treatment, there was no decrease in N95 amplitudes from baseline (1.8 + 0.96 µV p = 0.139).
Conclusions: :
Visual acuity outcomes mirrored prior prospective clinical data. There was no decrease in P50 and N95 amplitudes throughout the entire duration of the study. These findings indicate that VEGF inhibition with monthly injections of ranibizumab over 6 months likely do not lead to retinal damage.
Clinical Trial: :
www.clinicaltrials.gov NCT00500344
Keywords: age-related macular degeneration • electroretinography: clinical • drug toxicity/drug effects