Abstract
Purpose :
To examine how baseline patient characteristics and frequency of anti-vascular endothelial growth factor (anti-VEGF) therapy influence visual acuity (VA) outcomes in patients with neovascular age-related macular degeneration (nAMD).
Methods :
A meta-analysis of studies employing various injection frequency regimens with bevacizumab or ranibizumab for nAMD was performed. Only studies that measured VA with ETDRS letters were included. Four treat-and-extend studies (LUCAS, TREX-AMD, Abedi et al, Oubraham et al) were compared to randomized prospective trials employing monthly treatment (ANCHOR, MARINA, CATT, IVAN, VIEW), quarterly treatment (PIER and EXCITE), and PRN treatment (PRONTO, SAILOR, SUSTAIN, HARBOR, CATT, IVAN). Multiple linear regression was performed on the dependent variable of 12 month mean ETDRS letters gained versus the independent variables of mean 12-month injection count and multiple mean baseline characteristics (baseline ETDRS VA, age, central subfield thickness (CSFT), % classic CNV (choroidal neovascularization), and lesion size).
Results :
From the clinical trials above, 23 treatment arms were analyzed. Multiple linear regression revealed that the best fit model included only mean 12-month injection count as the dependent variable. Number of injections showed a linear correlation with number of letters gained at 1 year (r=0.68, R2=0.39). Mean letters gained did not increase beyond a mean of 9 or more injections in the first year. When all studies with fewer than 9 injections in 1 year were analyzed, there was greater linear correlation (r = 1.69, R2 = 0.52), suggesting that 52% of the variability in letters gained in the first year is related to injection frequency.
Conclusions :
AntiVEGF injection frequency plays a much greater role in 12-month VA outcomes than mean baseline features of the patient population, such as baseline ETDRS VA, age, CSFT, % classic CNV, and lesion size. There is a ceiling effect, highlighting a limitation of anti-VEGF therapy for nAMD. Fewer than 9 injections in the first year is associated with worse VA outcomes, highlighting treatment burden as a limitation of antiVEGF therapy for nAMD.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.