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Anti-VEGF therapies dominate retina presentations at AAO
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LAS VEGAS — Drugs that inhibit vascular endothelial growth factor were the focus of a great number of retina presentations here during the AAO’s annual meeting and the Retina Subspecialty Day that preceded it.
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“About 15 years ago, when I first started reading about anti-VEGF (vascular endothelial growth factor) therapy, I would have thought for sure we would be using it in diabetes first instead of macular degeneration,” said Robert L. Avery, MD. Since then, several anti-VEGF compounds have been evaluated for AMD and widely adopted by retinal subspecialists. Their use in other pathologies is being investigated with promising results.
VEGF useful in inflammation control, neuroprotection
Amid the excitement over the success of anti-VEGF drugs for treatment of AMD, additional less-appreciated benefits of the protein have gotten lost in the shuffle, according to Anthony P. Adamis, MD. Dr. Adamis discussed “two lesser appreciated bioactivities of VEGF” — inflammation control and neuroprotection — during Retina Subspecialty Day.
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He explained that VEGF causes inflammation, but with modifications it can be made to be anti-inflammatory and it also can provide neuroprotection.
“With regard to inflammation, VEGF is pro-inflammatory, but all isoforms are not the same,” said Dr. Adamis, the chief scientific officer of OSI Eyetech, the maker of Macugen (pegaptanib sodium, OSI/Pfizer).
In a study, he and colleagues substituted aspects of VEGF 164 and caused mutations that affected its ability to bind heparin, which contributes to inflammation. “If you get rid of that heparin-binding ability, you get rid of the ability to draw inflammatory cells,” Dr. Adamis said.
NIH to fund Avastin-Lucentis head-to-head study
The National Eye Institute and National Institutes of Health will fully fund a head-to-head trial of Avastin (bevacizumab, Genentech) and Lucentis (ranibizumab, Genentech/Novartis), the lead investigator announced here at Retina Subspecialty Day.
“After MARINA [Minimally classic/occult trial of the anti-VEGF antibody RhuFab V2 in the treatment of neovascular AMD], it became apparent to many of us that there needed to be a formal head-to-head trial comparing Avastin to Lucentis,” said Daniel Martin, MD, of Emory University.
The trial will enroll 1,200 patients at 40 centers, 20 of which have already been chosen. It will randomly assign each patient to receive one of the four treatment regimens: Lucentis fixed, Avastin fixed, Lucentis variable and Avastin variable. The regimens are based upon the fact that Avastin is generally given on a variable basis and Lucentis has only been formally tested in a fixed regimen, he said.
Variable dosing “is really the only way Avastin has been delivered, and to compare Avastin to Lucentis head-to-head you have to evaluate Lucentis in the same fashion,” Dr. Martin said.
The patients will be followed for 2 years. Dr. Martin said he hopes to present 1-year data in 2009. The main outcome measure will be changes in visual acuity, with secondary objectives including change in lesion size, fluid found on optical coherence tomography and cost, which he emphasized is not the sole purpose of the study.
“Cost is obviously an important parameter of this study, but there is much science to be learned here,” he said, noting that physicians are not sure whether there will be a loss of effectiveness in varying the dosing of Lucentis.
Dr. Martin added that the trial designers considered including combination therapies but decided it is “imperative to understand what the variable dosing of the drug by itself does first.”
AREDS’ simple scale proves predictive for 10 years
The simple 5-point scale developed by the Age-Related Eye Disease Study can effectively predict the likelihood a patient will develop advanced AMD over 10 years, according to Frederick L. Ferris, MD. He discussed this “exciting” method of explaining AMD risk to patients at the Retina Subspecialty Day.
The five-point scale allows physicians to assign 1 point for each risk factor, drusen or pigmentary changes in each eye. When totaled, the risk factor ranges from 0 to 4. A score of 0, or no risk factor, represents a 0.5% risk; 1 factor, 3%; 2 factors, 12%; 3 factors, 25% and 4 factors, 50% risk.
Although risk naturally increases with age, a patient’s initial risk factor, determined easily during a routine examination, held true through the study’s 10-year follow-up, he said.
“If you have no risk factors, you remain at no risk even after a decade,” Dr. Ferris said.
Most of these presentations appeared first as live coverage on PCONSuperSite.com.