Vascular Endothelial Growth Factor Blockers & Age-Related Macular Degeneration
A drug called pegaptanib (Macugen) blocks the action of a protein called vascular endothelial growth factor (VEGF), which promotes the growth of new blood vessels in the eye. Macugen selectively blocks only one form of VEGF. The FDA approved Macugen in late 2004, making it the first treatment for neovascular AMD that can be used in a wide range of people with the disease.
In 2006, the FDA approved another VEGF-blocking drug, ranibizumab (Lucentis), which blocks multiple forms of VEGF. Today, use of Lucentis is the standard of care for AMD patients, and vision outcomes are dramatically better than with other treatments. A genetically engineered antibody, Lucentis binds to VEGF, blocking its activity and thereby retarding new vessel growth.
Studies on Lucentis have found that individuals who received monthly mandatory treatments, on average, gained one to two lines of vision by the end of the first year of treatment. By comparison, individuals in these studies who received placebo or photodynamic therapy lost, on average, two to three lines of vision during the same period.
Lucentis is given by injection into the eye once a month for as long as two or more years. The downside is its cost: A single dose runs from $2,300 to $3,500 (including both drug and procedure costs).
Lucentis has many similarities to another drug called bevacizumab (Avastin). Approved for the treatment of colon and rectal cancer, Avastin has been used off-label for AMD. The National Eye Institute, a branch of the National Institutes of Health, is sponsoring a study that will compare the safety and effectiveness of the two drugs in AMD patients.