Clinical trial will demonstrate best treatment for AMD

A national clinical trial under way at the UW Department of Ophthalmology and Visual Sciences will help physicians determine which of two medications improve vision more in people with wet age-related macular degeneration.

Age-related macular degeneration is the most common cause of blindness in people older than 60. There are two forms, a wet and a dry form. The wet form causes damage when blood vessels form across the central vision area of the eye, called the macula. Those new vessels may leak or rupture and cause vision loss. In the past, age-related macular degeneration was treated with a laser to seal off the new vessels. A more recent type of laser, called a cold laser, is often used in combination with a drug that helps the laser energy target only abnormal blood vessels. Laser treatment does not restore vision that's been lost, and does cause its own damage. Treatment with lasers also needs to be repeated as new vessels grow. Even though it is among the best treatments available, researchers continue to investigate more effective procedures.

This new study, the Comparison of Age-related macular degeneration Treatments Trials (CATT) is funded by the National Eye Institute of the National Institutes of Health. Researchers are comparing injections of two medications that have been used for several years to determine whether one works better than the other. Led at the UW by Suresh Chandra, MD, a retina specialist in the Department, the study is looking at treatments that stop the release of vascular endothelial growth factor (VEGF), which is a factor in agerelated macular degeneration and some cancers, as well as in other eye disorders.

Injections into the eye to treat age-related macular degeneration is a relatively new technique. One drug, Avastin, was developed to treat cancer. An ophthalmologist in Miami, Philip Rosenfeld, MD, PhD, who understood the similarities between some cancers and some eye disorders, used a very small dose to treat a few patients with age-related macular degeneration. "He found that in his small study, his patients' vision improved," Dr. Chandra said.

This was the first time a treatment for wet macular degeneration was shown to restore a portion of lost vision.

Results from that study were published in a medical journal and ophthalmologists began using Avastin to treat patients with age-related macular degeneration. At the same time ophthalmologists were using Avastin for this, the company that created it was developing Lucentis, which is very similar to Avastin, but was developed specifically for use in the eyes. Avastin is much less expensive than Lucentis and appears to provide the same results. But until researchers compare the medications to each other in a controlled clinical trial, needed proof will not be available.

"Most people with age-related macular degeneration are using Medicare to pay for their treatments, so the cost difference is being borne by the government," Dr. Chandra explained. "If Avastin is as good as Lucentis, we will save the government billions of dollars. If it is not as good, we know we need to use Lucentis." Discussing injections into the eye can be a little bit daunting for patients. The surface of the eye is numbed first, Dr. Chandra said. "And these are the best treatments we have for this disease." The UW is among about 50 centers across the country participating in the CATT study. Every retina specialist in the department is participating, but there are specific study requirements so not all patients with macular degeneration qualify for the study.

This is one of the most important studies in eye research, Dr. Chandra said. "Depending on the outcome, the potential is there to provide excellent treatment at reduced cost."