Questions remain if anti-VEGF therapy influences atrophy in neovascular AMD
Analysis of the Harbor Study data could not definitively answer the question about whether anti-vascular endothelial growth factor (VEGF) therapies influence the development of atrophy in patients with neovascular age-related macular degeneration (AMD). However, investigators did find that the visual acuity (VA) continued to improve in patients treated with monthly and as-needed drug regimens and that certain risk factors can predict development of atrophy, according to Srinivas Sadda, MD.
Los Angeles-Analysis of the
The course of AMD is well recognized. The pathway of AMD progression proceeds from drusen deposition to atrophy and choroidal neovascularization (CNV) can be an interval event that develops in some patients, Dr. Sadda explained. Before the introduction of anti-VEGF therapy, scarring and vision loss occurred.
With the anti-VEGF drugs, physicians have the opportunity to reverse this process.
“However, we have also recognized that atrophy can still develop in many of these patients,” said Dr. Sadda, Doheny Eye Institute, Los Angeles.
Development of atrophy
Consideration of factors that lead to atrophy in treated neovascular AMD points to a few culprits.
“Natural progression of the underlying dry AMD may be responsible for development of atrophy,” he said. “Another possibility is that atrophy is associated with the destructive aspects of the exudative CNV disease process, or macular atrophy could actually be associated with anti-VEGF therapy independent of CNV.”
Thus, the challenge is assessing atrophy in CNV, Dr. Sadda said.
He pointed out that there is no consensus methodology by which to make this assessment or even a consensus name, for the purposes of this discussion he referred to it as macular atrophy.
“It can be difficult to identify atrophy with obscuring features from the CNV lesions,” he said. “To ideally study the impact anti-VEGF treatment, atrophy not adjacent to the CNV lesion should be investigated. However, this is a relatively rare event, the lesion can growth over time, and determining if the lesion is not adjacent to the atrophy is difficult to do.
“This may explain some of the differences between the rates of atrophy observed between the CATT and IVAN studies,” Dr. Sadda explained.
Between those two trials, the investigators did not find a consistent effect of the anti-VEGF drug as a risk factor for atrophy. “However,” Dr. Sadda said, “the atrophy rates did appear to be higher in patients treated with mandated monthly injections as opposed to the patients who received as-needed treatment in both studies.”
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