Drug delivery techniques for treating age-related macular degeneration.
BACKGROUND
Currently, the standard therapy for neovascular age-related macular degeneration involves the use of anti-vascular endothelial growth factor (VEGF) drugs, which are delivered by repeated office-based intravitreal injections. This treatment is generally very effective in stabilizing or improving vision, although repeated injections create a burden for patients, family members and physicians. In addition, the cumulative risks of endophthalmitis and other complications increase with the number of injections.


METHODS
In the clinic, much attention is focused on the relative efficacies of the three major anti-VEGF medications (bevacizumab, ranibizumab and aflibercept) as well as the most popular re-injection regimens (monthly, as-needed and treat-and-extend). In theory, intravitreal anti-VEGF drug delivery with sustained-release devices would offer similar visual results with fewer required re-injections. Various approaches have been studied, including noninvasive techniques, intraocular implants and colloidal carriers, such as liposomes, microparticles and nanoparticles.


CONCLUSIONS
Despite its theoretical appeal, sustained-release drug delivery will not replace current techniques unless it offers one or more advantages in efficacy, safety, convenience or cost. Currently, many patients maintain stable vision with intravitreal injections at intervals of 2 months or longer, so sustained-release techniques will have to lengthen these intervals substantially to become widely accepted. As we continue to collect data from clinical trials, the role of sustained-release techniques will become better defined.
University of Miami Miller School of Medicine, Bascom Palmer Eye Institute , 311 9th Street North, Naples, 34102 , USA.
Stephen G
SG
Schwartz
Ingrid U
IU
Scott
Harry W
HW
Flynn
Michael W
MW
Stewart
D020533:Angiogenesis Inhibitors / Q000008:administration & dosage*; D000818:Animals; D003692:Delayed-Action Preparations / Q000008:administration & dosage; D016503:Drug Delivery Systems; D006801:Humans; D058449:Intravitreal Injections; D008268:Macular Degeneration / Q000188:drug therapy*; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors
D020533:Angiogenesis Inhibitors; D003692:Delayed-Action Preparations; D042461:Vascular Endothelial Growth Factor A