Local patients benefit from newly approved drug for macular degeneration
Two years ago, Charlotte Knutson's deteriorating eyesight had reached the point where she could no longer read the newspaper, and limited her reading to large-print books. Worse than that, a retinal specialist told her that the condition causing her poor vision, macular degeneration, would not improve.
According to Knutson, the specialist said, “You have wet macular degeneration and there's nothing we can do. You'll just have to live with it.”
However, Knutson is now able to read the newspaper again after participating in a study at UC Davis Medical Center in which she received injections of a medication recently approved by the FDA for the treatment of macular degeneration.
“Lucentis™ is the first therapy to consistently improve both vision and function in wet age-related macular degeneration,” said Lawrence Morse, professor of ophthalmology and the principal investigator of the study at UC Davis. “In patients over 50 years old, age-related macular degeneration is the leading cause of vision loss in the United States.”
Nearly all of the patients treated with ranibizumab (95 percent) maintained their vision during the trial. Vision improved by at least three lines (or 15 letters) on the standard eye chart in up to 40 percent of these patients at one year. Ranibizumab is designed to inhibit the formation and leakage of new blood vessels in the back of the eye, the primary cause of central vision loss associated with this disease.
In age-related macular degeneration, hardening of the arteries deprives the central retina, or macula, of oxygen and nutrients, leading to loss of central, rather than peripheral, vision.
“As patients approach 80 years of age, 12 percent, or one of eight people, will have advanced age-related macular degeneration with vision loss in at least one eye,” Morse said. “Over 200,000 patients per year develop advanced age-related macular degeneration, and it is estimated that by the year 2020 over 3 million people will have the disease.”
About 10 percent of age-related macular degeneration patients suffer from the wet, or “neovascular” form of the disease. In wet age-related macular degeneration, oxygen deprivation triggers “vascular endothelial growth factor,” which drives the growth of delicate new blood vessels. These tiny capillaries can break and leak, causing bleeding behind the eye and centralized blind spots.
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Injected into the middle cavity of the eye, ranibizumab is an antibody fragment that binds and inhibits vascular endothelial growth factor. For two years, Morse and his research team administered monthly injections for two years to eight patients divided into two groups. One received ranibizumab, while the other received a placebo.
“The results of the study demonstrated remarkable and similar results,” Morse said. “Lucentis™ reduced the risk of moderate to severe loss in 95 percent of the patients, compared to only 62 percent of the non-Lucentis group. After the first year, 75 percent of the patients treated with Lucentis maintained their vision compared to only 29 percent of those not receiving Lucentis. Most surprising, between 24-to-40 percent of the Lucentis group actually improved their vision compared to only around 4 percent of those not receiving the drug.”