Macular Degeneration 101

FDA Approves Lucentis as a New Treatment for Macular Degeneration

July 2006

On July 1, 2006 the U.S. Food and Drug Administration (FDA) approved Lucentis™ (ranibizumab) for the treatment of neovascular (wet) age-related macular degeneration (AMD). Wet AMD accounts for approximately 10% of the cases of macular degeneration, but it is the most severe form of the disease in terms of loss in central vision. Individuals with dry AMD are at risk for developing the wet form. Wet AMD is caused by the development of abnormal blood vessels in the central or macula region of the retina. These blood vessels can leak causing macular scarring and permanent loss in central vision.

Lucentis developed by Genentech is an antibody fragment that binds to VEGF-A, a protein that is required for blood vessel formation. This interaction prevents VEGF-A from binding to receptors on the surface of endothelial cells and as a result new blood vessels can not form. In results of two large Phase III clinical trials, 95% of patients with wet AMD receiving monthly intravitreal injections of Lucentis showed no significant visual loss over a 2 year period, while up to 40% of the individuals showed measurable improvement in vision over this time period. Importantly, this is the first time that a treatment for AMD has increased rather than simply stabilizing the vision of some affected individuals.

Lucentis is a humanized monoclonal antibody derived from Avastin (bevacizumab) which was also developed by Genentech and approved by FDA for the treatment of colon cancer. One injection of Lucentis is expected to cost about $1950 with monthly injections required for maximum benefit. Avastin is over 100 times less expensive than Lucentis. However, to date there have been no systematic studies reported comparing Lucentis with Avastin for wet AMD.

The successful clinical trials reported for Lucentis is a break-through in the development of treatments for wet AMD and offers hope for stabilizing and in some cases improving the vision of individuals experiencing progressive vision loss. AMD is the leading cause of legal blindness in the U.S. for individuals over the age of 55. The number of people affected by AMD is expected to increase substantially in the future as individuals live longer and are exposed to environmental insults. The development of Lucentis as a treatment for AMD is a clear example of the benefits of basic and clinical research for the treatment of eye diseases.

Exciting new weapons are emerging in our fight against Age-related Macular Degeneration (AMD), the leading cause of severe vision loss in adults over 50 years of age in the U.S.A. and the developed world. For decades, researchers have toiled to understand the mechanics of AMD and in the doing so, have begun to unlock the mysterious chemical signals that trigger degeneration and bleeding in the retina that leads to blindness. Abnormal blood vessel growth and leakage of blood from “old” normal and “newly formed” abnormal retinal blood vessels are the hallmark destructive processes of wet AMD. Scientists are targeting new drugs as signals that start these destructive processes.

Macugen

Macugen (pegaptanib sodium injection, Pfizer/Eyetech) was approved before Lucentis was available and may be used in some cases. It was approved by the U.S. Food and Drug Administration (FDA) in January 2005. Macugen binds to a destructive form of protein signal called VEGF, Vascular Endothelial Growth Factor. Many different forms of VEGF exist, triggering beneficial and destructive processes in the human body. Macugen binds to a destructive form of VEGF. Macugen stops this form from causing new blood vessels to grow and bleed into the retina. Macugen also stops the bad form of VEGF from causing normal and abnormal retinal blood vessels to become incompetent and leaky, also part of the process that causes wet AMD. Macugen works by being injected into the eye in the doctors’ office, a relatively painless procedure. The drug is typically injected every 6 weeks, but may be given prior to other treatments such as photodynamic therapy with Visudyne, thus reducing the need to repeat these treatments as frequently. Medical studies have shown that it is successful in helping to prevent vision loss from wet AMD.