Bevacizumab reported to improve vision in macular degeneration patients
PHILADELPHIS, PA - The prospect of having to undergo an injection into one’s eyeballs is by no means a welcome thought. However, when the alternative is going blind, the treatment becomes appealing. Researchers at the Retina Service of the Wills Eye Institute at Thomas Jefferson University (Philadelphia, Pennsylvania) reported that monthly injections of the drug bevacizumab markedly improved vision in patients suffering from macular degeneration. Their findings were published in the March 2012 edition of the American Journal of Ophthalmology.
Macular degeneration is an eye disorder that damages the macula, which is the central portion of the retina. This damage results in difficulty to see fine details and can progress to blindness. This makes it difficult to see fine details. The patients enrolled in the study suffered from neovascular age-related macular degeneration, also known as “wet” macular degeneration. This type of macular degeneration occurs in only about 10% of individuals with the condition. Brittle blood vessels deteriorate and new, abnormal, and very fragile blood vessels grow under the macula. These vessels leak blood and fluid, which leads to macular damage. Although only about 10% of individuals have this form, it causes most of the vision loss associated with adult macular degeneration. The condition is referred to as adult macular degeneration because it is most common in people over the age of 60.
The study group was comprised of 73 patients who suffered from neovascular age-related macular degeneration that did not respond to traditional treatment. They were treated with monthly injections into the vitreous humor. (The vitreous humor is a thick fluid that fills most of the interior of the eyeball.) The monthly treatments were continued until leakage of fluid was no longer observed by a procedure known as optical coherence tomography. At this point, the treatment intervals were lengthened sequentially by two weeks until signs of fluid leakage recurred. The intervals between injections exudation were reduced until a maintenance level was reached. The outcome measures included improvement in visual acuity, the number of injection, change in retinal thickness, adverse effects, and annual medical cost.
The patients were followed for an average of 1.41 years. At one year, the average degree of visual acuity improvement was from 20/230 at baseline to 20/109 at one year. The average number of injections for this period was 7.94. The average retinal thickness decrease was from 316 μm to 239 μm. The average direct medical cost was $3,493.85.
The authors concluded that eyes with this type of macular degeneration were found to undergo significant visual improvements when treated with intravitreal bevacizumab via a treat-and-extend regimen. They noted that the treat-and-extend regimen resulted in lower medical costs than a fixed, monthly treatment.
Interestingly, bevacizumab is an anticancer medication also known by the trade name Avastin, which is manufactured by Genentech. The drug has Food and Drug Administration (FDA) approval to treat cancer but not eye disease. However, many retina specialists use Avastin off label because it costs only about $50 an injection, compared with $2,000 for ranibizumab (Lucentis), also manufacture by Genentech drug. This drug has the same mode of action as bevacizumab and is FDA approved as an eye treatment. At present, both drugs appear to be equally effective for treatment of macular degeneration.
Avastin came under FDA scrutiny last August when the agency reported that at least 12 patients in Miami, treated at three clinics, had suffered eye inflammations. While all had impaired eyesight before the treatment, some lost all remaining vision in the treated eye. All the infections involved a single lot of Avastin, which was traced to a single pharmacy in Hollywood, Florida; the pharmacy had repackaged the drug for use in the eye. In Tennessee, four patients received injections contaminated by bacteria. The Avastin doses were prepared in the pharmacy of the Veterans Administration Hospital in Nashville. One of the patients, Lloyd Mason Sylvis, 77, suffered an eye infection of Streptococcus viridans that spread to his brain. His son said that he is permanently blinded and permanently brain damaged. The Florida patients were apparently infected with Streptococcus oralis. It appears that bacterial contamination is solely responsible for the problem.
Heredity is a risk factor for the development of macular degeneration. Other risk factors include:
- Cigarette smoking
- High-fat diet
- Female gender
Reference: American Journal of Ophthalmology