Current Research & Treatment

Drug Therapy
Eye centers around the country -- including the Casey Eye Institute – are actively studying anti-angiogenic drugs in the treatment of wet age-related macular degeneration. These drugs, such as Macugen (Eyetech), anecortave acetate (Alcon), and Lucentis (Genentech) are designed to block growth factors that cause abnormal blood vessel growth in the back of the eye.

In the wet form of macular degeneration, these errant blood vessels multiply in the macula, where they leak, bleed, and form scar tissue. This new blood vessel growth, termed “neovascularization,” eventually can harm the light-sensitive cells of the macula, permanently damaging central vision.

FDA Approves New Drug Treatment for AMD
A new therapy to slow vision loss in people with active retinal bleeding from the wet form of AMD was approved by the U. S. Food and Drug Administration in December. Macugen is the first in a new class of ophthalmic drugs designed to block a protein called vascular endothelial growth factor (VEGF), which is an important factor in the development of abnormal blood vessels in the eye.

The Casey Eye Institute was one of 117 clinical centers worldwide that tested the safety and efficacy of Macugen in two trials of patients with wet AMD. The drug, given every six weeks by injection directly to the eye, stabilized vision in 70 percent of patients, compared with 55 percent on placebo, according to a 54-week late-stage trial of 1,168 patients. Macugen was effective at all of the doses tested and in all of the forms of wet AMD. The drug appeared to be safe, with no increased risk of cardiovascular or other systemic effects.

“Like photodynamic therapy (PDT), Macugen is a clinically proven treatment option for patients in the active phase of wet AMD, meaning they currently are experiencing abnormal leaking and/or bleeding underneath the retina,” explained Michael Klein, M.D., director of the Macular Degeneration Center and principal investigator of the Macugen study.

A new study is under way at CEI to learn if Macugen, administered in combination with photodynamic therapy, is safe and effective. Other medications to halt or prevent abnormal blood vessel growth are still being tested. For example, anecortave acetate (Retaane) also has the properties of inhibiting blood vessel growth and is injected under the lining of the eye. Casey investigators are evaluating anecortave acetate’s ability to prevent the development of wet AMD in high-risk eyes.

Currently, these anti-angiogenic drugs are delivered in and adjacent to the eye by injection. In the future, implantable drug delivery systems may be developed which would allow the medication to be slowly released over a long period of time, said Dr. Klein. Macugen, developed by Eyetech Pharmaceuticals, should be available commercially this spring.

Anecortave Acetate
Investigators at the Casey Eye Institute are also evaluating the safety and effectiveness of a steroid compound called anecortave acetate (Retaane). This drug, which is injected adjacent to the eye, is also designed to prevent abnormal blood vessel growth. A new study is underway to determine if anecortave acetate can prevent abnormal blood vessel growth in the good eye of patients with wet AMD in the other eye.

Patients who have lost vision from wet AMD in one eye are in danger of developing the wet form in the other eye within five years. In this new, multi-center clinical trial, the medication is being administered alongside the healthier eye in order to prevent wet AMD from developing.

This is a departure from previous drug studies because investigators are trying to preserve vision in at-risk patients by preventing the vulnerable eye from developing abnormal blood vessels.

Anecortave acetate previously has been studied in other clinical trials at the Macular Degeneration Center and other research institutions. For more information about this study, please contact Susan Nolte, study coordinator, at 503-494-3616.

Gene Therapy
Casey scientists, in collaboration with other U.S. research centers, have also begun the first gene therapy trial for macular disease in the U.S. The study is evaluating the safety of a drug delivered by gene therapy. The study drug, called AdPEDF (GenVec), contains a non-replicating virus and gene. The virus is used to get the gene for pigment epithelium-derived factor (PEDF) inside the cells of your eye. The PEDF gene produces the PEDF protein, which is naturally present in the eye and regulates the formation of blood vessels. The hope is that the study drug will slow or stop the growth of abnormal blood vessels. For information about these studies at Casey, see Anti-Angiogenic Drug Studies for Wet AMD.

Think Locally
Anti-angiogenesis studies for wet AMD are not new. However, in the last decade, most of the drugs studied were administered systemically. Three of those drugs – alpha-interferon, thalidomide, and prinomastat (Agouron Pharmaceuticals) – have been found to be of no benefit after clinical trial testing.

Because drugs like Macugen, anecortave acetate and AdPEDF are delivered locally in and around the eye, patients can get a more concentrated dose with fewer side effects than if the drug was administered systemically. In the future, it is expected that these medicines, if proved effective, may be delivered to the macula via an implant in or adjacent to the eye instead of by injection.

Can Vision Be Restored?
Although anti-angiogenic drugs may be successful in preventing future blood vessel growth, they cannot bring back vision lost to age-related macular degeneration.

When bleeding occurs and the abnormal vessels grow, scar tissue eventually forms, damaging the macular cells and causing vision loss. At this time, drugs or other treatments for AMD are not capable of repairing these damaged cells. Scientists are investigating other methods to replace these cells, but results are still far into the future.

Yet there is still reason to be optimistic. Initial results from these drug studies are encouraging, and further evaluation of these and other drugs is ongoing.

For more information about these studies, visit these web sites:

EyeTech (Macugen) – Click on Clinical Trials

Alcon Labs (Anecortave Acetate)

Genentech (Lucentis)

GenVec (AdPEDF)



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