Abstract
Purpose:
Visual acuity (VA) improvement as primary endpoint in diabetic macular edema (DME) trials varies considerably. In trials investigating the efficacy of different anti-vascular endothelial growth factor (VEGF) treatments (ranibizumab or aflibercept), this variation may be attributed to differences in study design, baseline VA, or other inclusion criteria. To address the questions whether baseline VA is a predictor of VA and whether VA gains across trials are comparable, we conducted a retrospective analysis of clinical trials with anti-VEGFs in DME.
Methods:
Data from different clinical trials (RESOLVE, RISE & RIDE, RESTORE, RETAIN, DRCR.net, Da VINCI, VIVID and VISTA) with different treatment regimens (monthly, pro-re-nata [PRN], fixed, treat-and-extend [T&E]) were analyzed for a correlation between mean baseline VA and mean VA gain at Month 12. Data from 1387 DME patients across 9 randomized clinical trials were included.
Results:
The mean baseline VA covered a range from 56.9-64.8 letters (early treatment diabetic retinopathy study [ETDRS]). At month 12, VA gain ranged from 6.8-12.9 ETDRS letters across trials with different anti-VEGF treatment regimens. Correlation analysis resulted in a strong inverse correlation between mean baseline VA and mean VA gain at month 12 (R2=0.81). There was a VA plateau at about 70 (range:68.5-71.9) ETDRS letters for the anti-VEGF treatment groups from all trials, regardless of the dosing regimen and agents.
Conclusions:
Our analysis strongly suggests that baseline VA is a main predictor for VA gain in patients with DME following anti-VEGF treatment. Thus, change in VA is of limited value for comparisons of anti-VEGF treatments across trials with diverse treatment regimens, agents, and patients with different mean baseline VA. Additionally, optimal VA outcomes were observed with T&E and PRN dosing in DME trials. These individualized dosing regimens can thus be helpful in lessening treatment burden.