New Drug Studied for Macular Degeneration

A drug therapy that blocks new blood vessel growth is under investigation at Baylor College of Medicine as a treatment for age-related macular degeneration, or AMD, a progressive disorder that may lead to loss of central vision.

"The potential for this treatment is vast," said Dr. William F. Mieler, professor of ophthalmology at Baylor and principal investigator of the study. "The medication used in this study may benefit patients who otherwise have to live with the life-altering effects of this disease."

AMD is the leading cause of visual impairment in patients beyond age 60. In many cases, the visual loss is due to the "wet" form of the disease that is caused by the growth of abnormal, leaky blood vessels in the eye, beneath the center of the retina. These vessels leak fluid and eventually cause scar tissue, which interferes with vision.

To block the growth of these vessels, an agent known as anti-vascular endothelial growth factor (anti-VEGF) is placed in the eyes of patients enrolled in the study. During the treatment, doctors put anti-VEGF into the center of the eye in the vitreous cavity. The entire process takes less than five minutes and is done under a local anesthetic. The procedure must be repeated every six weeks during the first year.

"We have to catch this disease process before scar tissue forms and causes irreversible damage to the eye," Dr. Mieler said, "This condition takes away the patient’s central vision, making objects seem blurry or distorted. It makes completing routine tasks very difficult, or even impossible."

AMD is caused by the deterioration of the central portion of the retina, the area known as the macula. The macula records images and transmits them via the optic nerve to the brain, controlling the ability to read, drive a car, recognize faces or colors, or see objects in fine detail.

Thermal laser therapy and photodynamic therapy are currently used to treat age-related macular degeneration. These therapies use lasers to seal off blood vessel growth and halt further degeneration.

"The problem with the thermal laser is that it can cause some damage to the retina," Dr. Mieler said. "So while patients treated with the laser are better off than patients who were not treated, the visual results are quite disappointing."

While photodynamic therapy is not as harmful to the retina, it only stabilizes vision or slows down the rate of impairment. Approximately 15 percent of patients have better vision following photodynamic therapy.

Anti-VEGF therapy has been studied as a treatment for a wide range of diseases and has received recent publicity as a potential cancer therapy. Eyetech Pharmaceutical is the sponsor of the study, which is the first to investigate the use of this anti-VEGF agent in the eye.

For more information, contact the Age-Related Macular Degeneration Center at the Cullen Eye Institute, Baylor College of Medicine, (713) 798-3536.

E-Mail: tmcinfo@texmedctr.tmc.edu
URL: http://www.tmc.edu/tmcnews/03_01_02/page_22.html