March 20, 2013
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Anti-VEGF offers comparable benefits in phakic, pseudophakic eyes with AMD
Intravitreal ranibizumab injections for neovascular age-related macular degeneration yielded similar outcomes in phakic and pseudophakic eyes, according to a study.
The retrospective review included 120 eyes of 110 patients with neovascular AMD; 75 eyes were phakic and 45 eyes were pseudophakic. Average follow-up was 18 months.
Phakic and pseudophakic patients received three monthly loading dose injections of Lucentis (ranibizumab, Genentech). Subsequent re-treatment was performed on an as-needed basis. Best corrected visual acuity, IOP, anterior chamber parameters and retinal images were assessed at 4 weeks and 3, 6, 9 and 12 months after injection.
Baseline mean BCVA was 0.88 in the phakic group and 0.86 in the pseudophakic group.
The average number of injections was 3.87 in the phakic group and 3.62 in the pseudophakic group; the between-group difference was statistically insignificant.
Study results showed that at final follow-up, mean BCVA was 0.75 in the phakic group and 0.74 in the pseudophakic group. Both improvements were statistically significant (P = .01 in the phakic group and P = .02 in the pseudophakic group), but the between-group difference in visual gain was insignificant.
Central macular thickness decreased significantly in both groups, but the between-group difference was not significant, the authors said.
Perspective
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Carl D. Regillo, MD
The vitreous changes in many ways after cataract extraction. Compared to age-matched phakic patients, the vitreous tends to have a greater degree of liquefaction and a higher percentage of posterior hyaloid separation. Based on these findings, it is plausible that there are significant differences in the pharmacokinetics and the pharmacodynamics of intravitreal anti-VEGF agents between pseudophakic and phakic eyes. Theoretically, there could be faster clearance of drugs or greater efficacy via better drug penetration in pseudophakic eyes. In practice and in clinical trials, there is considerable variability between patients in terms of durability of effect of a given anti-VEGF injection and degree of efficacy, regardless of the specific drug used, and we observe shorter duration of effect when these drugs are injected in vitrectomized eyes. Recently, it was shown in a study by Muether et al (
Ophthalmology. 2012;119:2082-2086) that the duration of VEGF suppression by ranibizumab in human eyes with neovascular AMD can range from 26 to 49 days. Could lens status account for the variable degree or durability of effect that we observe in practice? It does not appear to be the case to any significant degree based on this retrospective study by Sun Baek and colleagues.
Carl D. Regillo, MD
OSN Retina/Vitreous Board Member
Disclosures: Regillo receives grant support and consulting fees from Genentech and Regeneron.
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