Eye drops may one day be an option for age-related macular degeneration (AMD) treatment, according to a new study. Though previous efforts at topical AMD therapy met with little success, researchers have developed a topical delivery of ranibizumab and bevacizumab that, at least in an animal model, it provides the same outcome as injected therapy.

A recent study investigated cell-penetrating peptides (CPP) as ocular drug delivery vehicles. Researchers used drops with CPP-mediated topical delivery to transport anti-vascular endothelial growth factor (anti-VEGF) therapy into the posterior segment of rabbit and pig eyes. The study tested the CPP and anti-VEGF mix’s efficacy using disease models in rodents with established models of neovascularization.

In rabbits, the CPP+bevacizumab drop delivered 4.0±2.3μg/retina at 24 hours—significantly higher than controls. This increased over three days to 83.31±39.72μg/retina and cleared from the retina over seven days. In the pig’s eyes, the CPP+ranibizumab eye drop delivered 1.7±0.4μg/mL and the CPP+bevacizumab eye drop delivered 1.1±0.3μg/mL, all significantly higher levels than CPP, saline, ranibizumab or bevacizumab drops alone.

Subjects that had an anti-VEGF intravitreal injection and those receiving CPP+anti-VEGF eye drops had significantly lower areas of neovascularization than the negative control eyes.

Researchers noted that eye drops could deliver anti-VEGF treatment to the back of the eye without causing patients distress or causing possible side effects such as retinal tearing. By removing the need for injections, patients could take ownership of their treatment program.