Avastin is used to treat several eye and retina diseases, like age-related macular degeneration (AMD). AMD is the leading cause of blindness in people over 50 years of age in the United States. AMD is caused by the breakdown of the central portion of the retina, called the macula (the highly sensitive part of your eye that works like the film in a camera).
Avastin is also used to treat diabetic macular edema and central retinal vein occlusion (CRVO).
The macula is responsible for the detailed central vision in the eye that is used for reading fine print, recognizing faces and driving your car. There are two types of macular degeneration: dry and wet.
In the wet form of macular degeneration, abnormal blood vessels grow in the back of the eye. Sometimes these vessels leak blood or fluid. This leakage causes blurred or distorted vision. Without treatment, vision loss may be quick and severe.
There are other eye conditions that cause loss of vision due to abnormal growth of blood vessels in the back of the eye. These eye diseases can even occur in young patients. They include conditions such as high myopia (nearsightedness), histoplasmosis, angioid streaks, and eye injury. Without treatment of this leaking, vision loss can be quick and severe.
Chronic macular edema, or swelling around the macula, is a condition that affects vision but does not respond well to the usual treatment drugs, like eye steroids. It can occur with conditions such as central retinal vein occlusion and diabetic retinopathy. Without effective treatment, vision loss could get worse or become permanent.
What is off-label use and how does this pertain to Avastin
Avastin was not initially developed to treat eye conditions. Based upon the results of clinical trials that demonstrated its safety and effectiveness, Avastin was approved as a chemotherapy drug by the U.S. Food and Drug Administration (FDA) for the treatment of metastatic colorectal cancer. As a condition of approval, the manufacturer produced a “label” explaining the indications, risks, and benefits. The label explains that Avastin works by blocking a substance known as vascular endothelial growth factor or VEGF. Blocking or slowing VEGF helps prevent further growth of the blood vessels that the cancer needs to continue growing.
Once the FDA approves a device or medication, physicians may use it “off-label” for other purposes. The doctor should be well informed about the product, base its use on firm scientific method and sound medical evidence, and maintain records of its use and effects. Ophthalmologists are using Avastin “off-label” to treat AMD and similar conditions because research indicates that VEGF is one of the causes for the growth of the abnormal vessels that cause these conditions. Most patients treated with Avastin have less fluid and more normal-appearing maculas, and their vision improves. Avastin is also used to treat macular edema in some diabetic patients.