Patients with mild visual loss from diabetic macular edema (DME) benefit similarly, on average, from intravitreous (IVT) injections containing any of three anti-VEGF medications, a head-to-head comparison trial has demonstrated. But in eyes with best-corrected acuity of 20/50 or worse, the visual gains at 12 months were significantly greater with one of the drugs, aflibercept (Eylea).1
“This is really the first study that I’m aware of that has shown a difference in therapeutic impact between one anti-VEGF agent and another one in diabetic retinopathy,” said study coauthor John A. Wells III, MD, who is in practice at Palmetto Retina Center and chair of ophthalmology at the University of South Carolina, in Columbia.
The results were reported in the New England Journal of Medicine by the Diabetic Retinopathy Clinical Research Network (DRCR. net). Since 2003, this nationwide collaborative, funded by the National Eye Institute, has been overseeing landmark studies to identify effective treatments for diabetic eye diseases.
Study details and results. This latest study, Protocol T, was an 89-site, randomized clinical trial comparing the results of IVT therapy with aflibercept, bevacizumab (Avastin), or ranibizumab (Lucentis) in 660 patients with DME. At 12 months, the patients’ visual gains were evaluated on a 0 to 100 letter score, with 85 letters approximately 20/20.
In the eyes that were correctable to a letter score of 78 to 69 (approximately 20/32-20/40) at baseline, the mean gain after 12 months was 8.0 letters with aflibercept, 7.5 with bevacizumab, and 8.3 with ranibizumab (p > .50 for each pairwise comparison).
But if the initial letter score measured less than 69 (approximately 20/50 or worse), the mean improvement a year later was 18.9 letters with aflibercept, 11.8 with bevacizumab, and 14.2 with ranibizumab (p < .001 for aflibercept vs. bevacizumab; p = .003 for aflibercept vs. ranibizumab; p = .21 for ranibizumab vs. bevacizumab).
Clinical implications. Dr. Wells said that these acuity-specific findings will help clinicians weigh the differences between a drug that costs about $50 per dose (bevacizumab) and the costlier aflibercept (about $1,950 per dose) or ranibizumab (about $1,200 per dose).
“It’s reassuring to know that if the patient has 20/40 or 20/32 vision before treatment, you’re going to get about the same level of improvement on average with any of the three drugs, including Avastin,” Dr. Wells said. “You can be very comfortable considering using it in this way.”
More study needed. Additional papers are planned to look at the results in more detail, Dr. Wells added. “Because one thing that we did see in this study was that the eyes treated with Avastin had significantly less reduction in the macular edema than occurred with the other two drugs,” he said. “The long-term impact of this is unknown, but patients are being treated in the study for two years, so we hope to learn more from the second-year results.”
1 The Diabetic Retinopathy Clinical Research Network. N Engl J Med. 2015 Feb. 18. [Epub ahead of print.]
Dr. Wells reports grant support, outside of the work in this study, from Genentech, Regeneron, Allergan, and KalVista.
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