Treatment for Macular Degeneration
There is no outright cure for macular degeneration, but some treatments can slow its progression or possibly improve vision.
Visudyne Drug Treatment
Visudyne was the first drug therapy for treatment for the wet form of this disease. It is only for patients who have new blood vessel growth under their retina in a well defined and distinctive pattern known as "predominantly classic.: About 40-60 percent of new AMD patients have this form of age-related macular degeneration, according to Novartis.
With this treatment, the doctor injects Visudyne into the patient's arm. The drug is then activated as it passes through the retinal blood vessels by shining a non-thermal laser into the eye. Activating Visudyne produces a chemical reaction that will destroy any abnormal blood vessels. About twice as many Visudyne patients show improved vision, or 1 in 6 patients as those who do not use Visudyne therapy.
Vitamins and Minerals
Research suggests that antioxidant vitamins, such as vitamins A, C and E, may protect the macula from becoming damaged. The AREDS study, which involved more than 3,600 people, found that supplementation with vitamins C and E, beta-carotene and zinc reduced certain patients' risk of progressing to advanced AMD by about twenty-eight percent.
These researchers recommend that patients at risk of developing advanced AMD should consider taking antioxidant and zinc supplements such as:
- 500 mg of vitamin C
- 400 IU of vitamin E
- 15 mg of beta-carotene
- 80 mg of zinc oxide
However, more studies are necessary, especially on the long-term effects of high-dose supplementation. Furthermore, too much of any vitamin or mineral may affect the body's ability to absorb other important nutrients.
Macugen Drug Treatment
Macugen drug treatment uses a therapeutic molecule to attack a protein that causes abnormal blood vessel growth in the eye. It was approved by the FDA in December of 2004. The drug is administered through injections into the eye, with treatments required every six weeks. In clinical trials, some macular degeneration patients experienced slower rates of vision loss, and some even had restored vision.
Laser photocoagulation is no longer used as a treatment, but can help wet AMD patients by destroying or sealing new blood vessels to prevent leakage. The procedure risks producing scars, perceived as blind spots by the patient. Scientists are working on ways to reduce scarring and are also studying laser treatments for dry AMD.
Other Developing Drugs
Genentech is researching the possibility of using a form of its colorectal cancer treatment drug, Avastin, as a therapy for AMD. This is known as Lucentis. Lucentis is similar to Macugen in that the drug targets a type of protein thought to contribute to AMD development.
Genaera Corporation is investigating a drug called Evizon, which the company reports will work to disrupt cells responsible for abnormal blood vessel growth creating macular degeneration. Results from a small study in early clinical trials indicated that, in some cases, vision may be improved. In October 2004, Genaera launched a second phase of clinical trials for treating AMD patients using both Evizon and Visudyne.
Late in 2005, Alcon announced that it received regulatory approval from Australia and will continue to seek FDA approval in the U.S. for Retaane, a substance that attacks enzymes which allow abnormal blood vessel growth by weakening the walls of retinal blood vessels. An advantage of Retaane is that it is not administered with a needle but is inserted behind the eye. Another is that treatments are spaced about six months apart.
Early U.S. clinical trials also are underway for a different drug produced by OXiGENE Inc. This drug is known as combretastatin. The anti-tumor drug looks to prevent development of abnormal blood vessels, which could be beneficial in slowing or halting development of macular degeneration.