Research Updates

Age-Related Macular Degeneration (AMD):
Macular degeneration is the leading cause of vision loss and blindness in people 50 and older. The National Eye Institute (NEI) says that Americans with moderate to severe AMD will number 17 million by 2020 more than double the current figure.

A number of national clinical studies have and are being conducted into the causes and treatment of AMD, as well as other eye diseases. The ISPB also funds, each year, research starter grants to Illinois education/medical institutions on various eye topics. Here are a few recent national studies:

Macugen® (pegaptanib sodium injection), distributed by Eyetech Pharmaceuticals and Pfizer Inc.,  Received FDA approval in December 2004 for the treatment of AMD.

Macugen is injected into the eyes once every six weeks for approximately 48 weeks under local anesthesia. It targets vascular endothelial growth factor(VEGF), a protein that triggers the abnormal blood vessel growth and leakage that leads to central vision loss in people with “Wet” AMD.

In clinical trials (Massachusetts Eye and Ear Infirmary, Boston and Harvard Medical School),Macugen’s safety and effectiveness was tested for two years. In both studies, vision loss slowed significantly in “Wet” AMD patients
(Sources: New England Journal of Medicine, Dec. 30, 2004; Eyetech Pharmaceuticals, New York).

Avastin™, distributed by Genentech, received FDA approval for cancer treatment in December 2004. Researchers in early studies found that Avastin substantially reduced blood vessel leakage contributing to vision loss that occurs in the “Wet” form of AMD. Unlike Macugen, Avastin is administered by intravenous injection (IV).
More studies are needed, though, to determine if the benefits of Avastin as a macular degeneration therapy outweighs the risks. When Avastin is used to treat cancer patients it has been shown to increase risk of stroke and heart attack
(Source: www.allaboutvision.com, March 2005).

Gene-based therapy. “Physicians hope gene-based therapy will increase the production of a protein in short supply in the eyes of people with a special type of macular degeneration, thus improving or stabilizing their vision,” stated a Baylor College of Medicine ophthalmologist.

A preliminary study at Baylor’s Cullen Eye Institute, sponsored by GenVec Inc., was specifically conducted to check the safety of the compound AdPEDF, which is comprised of PEDF ( pigment epithelium-derived factor), a natural inhibitor blood vessel formation, combined with an inactivated virus, known as a vector. The compound is injected into the target cells of the eye to stimulate the eye’s production of PEDF in patients with AMD.

It was found that AdPEDF was safe and well-tolerated at all tested dose levels and at twelve weeks, approximately three-quarters of the patients had stable or improved vision.

“If the study’s future phases prove to be successful, those with AMD may have a more successful means of maintaining or improving their vision.”

Studies have also been conducted at other eye centers and schools of medicine
(Source: Meg Bolton, Baylor College of Medicine, Texas Medical Center News,
Jan. 15, 2005).

The Visionary, published as a service of the Illinois Society for the Prevention of Blindness,
is available upon request. The information contained in this issue,
taken from sources considered to be accurate,
does not replace the need for professional eye care consultations and treatments.

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