WEDNESDAY, Oct. 4, 2006 (HealthDay News) -- A new drug not only prevents vision loss linked to age-related macular degeneration, it also improves sight for as long as two years in patients afflicted with the disorder, two new studies show.
The drug, Lucentis (ranibizumab), also outperformed an established treatment that doctors typically use to keep the condition in check.
"Lucentis is the first drug ever that's actually causing improvement in vision, so that's a major, major breakthrough," said Dr. Robert Cykiert, a clinical associate professor of ophthalmology at New York University School of Medicine in New York City. He was not involved in either of the studies.
Lead researcher Dr. Philip J. Rosenfeld, of the University of Miami Miller School of Medicine, said that "in this study, the average vision went up as opposed to the average vision going down."
Rosenfeld, a professor of ophthalmology at the university's Bascom Palmer Eye Institute, was quick to point out that Lucentis is not a cure for age-related macular degeneration (AMD).
"This prevents the irreversible damage that occurs from the abnormal growth of blood vessels in the eye," he said. "If you catch it early, you can get spectacular vision improvement but if it's been there a year or longer, you won't get this significant improvement. If it's a couple of years and it turns into a scar, there's nothing you can do. You have a window of opportunity to get the treatment in."
Lucentis was approved for use against AMD by the U.S. Food and Drug Administration at the end of June, based on these and other studies.
The two new studies were both funded by drug makers Genentec and Novartis, which market Lucentis in the United States and abroad, respectively. The findings, from researchers at Genetech and institutions in the United States and Europe, appear in the Oct. 5 issue of the New England Journal of Medicine. Both trials have a longer follow-up than the studies on which the FDA based its approval.
AMD is a growing medical concern in the United States. Researchers have estimated that one-third of Americans will develop some form of the condition -- a leading cause of irreversible blindness -- by the age of 75.
The neovascular "wet" form of the disease, which is the subject of these studies, is characterized by the abnormal growth of new blood vessels in the retina. Although neovascular AMD accounts for only about 10 percent of all cases, it is responsible for most of the vision loss linked to the ailment.
Other drugs have been approved for AMD, but so far they only managed to keep the condition from deteriorating further.
Lucentis, a type of drug known as a "recombinant, humanized monoclonal antibody," works by neutralizing vascular endothelial growth factor (VEGF). VEGF is a naturally occurring molecule that helps fuel the formation of new blood vessels.
In the first trial, 716 patients with AMD were randomly assigned to receive injections of Lucentis (either 0.3 milligrams or 0.5 milligrams) or "sham" injections every month for 24 months. Injections were administered directly into the eye.
Visual acuity (the ability to make out visual details) improved by 15 or more letters in almost one-quarter (24.8 percent) of the 0.3-mg. group and one-third (33.8 percent) of the 0.5-mg. group, vs. only 5 percent of the sham group.
In other words, the average patient on Lucentis gained more than one line of visual acuity on a standardized eye chart, while patients receiving sham injections lost more than two lines, an accompanying editorial in the journal explained.
These treatment-linked benefits in visual acuity were still evident at 24 months, the researchers said. Side effects appeared to be minimal.
Effectively, Lucentis turned "wet" AMD back to "dry" AMD, Rosenfeld said.
In the second trial, researchers randomly assigned 423 patients to receive monthly injections of Lucentis (0.3 or 0.5 mg.) or monthly injections of Visudyne (verteporfin).
Slightly more than 94 percent of those receiving 0.3 mg. of Lucentis and 96.4 percent of those receiving 0.5 mg. lost fewer than 15 letters, vs. 64.3 percent in the Visudyne group.
Visual acuity improved by 15 letters or more in 35.7 percent of the 0.3-mg. group and 40.3 percent of the 0.5-mg. group, vs. only 5.6 percent of the Visudyne group.
Again, this translates into a gain of about two lines of acuity on an eye chart at one year for the Lucentis group and a loss of about two lines for the other group.
Interestingly, the cancer drug Avastin (bevacizumab) has many of the same benefits as Lucentis at a fraction of the cost.
According to the authors of an accompanying commentary and perspective in the journal, a single dose of 0.5-mg. Lucentis costs almost $2,000, while a dose of Avastin costs $550. Both drugs are made by the same company, Genentech. At this point, it appears that Lucentis would have to be administered indefinitely, they added.
Because it is not FDA-approved for the eye indication, doctors have long been using Avastin "off-label," the experts noted.
Both the editorial and a perspective article called for direct, head-to-head comparisons of Avastin and Lucentis -- apparently with an eye to getting the former FDA-approved for use against AMD.
"All clinical studies so far indicate that the drugs are pretty much equivalent," Cykiert said.
More information
Learn more about age-related macular degeneration from the U.S. National Eye Institute.
