New drug found effective in treating age-related vision loss

NEW YORK: A new drug has been identified, which has been found to prevent vision loss caused by age-related macular degeneration. Ophthalmologists find that the drug, Lucentis (ranibizumab), also improves sight for periods extending to two years in patients suffering from this disorder. The drug has also been found to be a better therapy than the existing treatment that doctors prescribe, that is, use of verteporfin, which combines drug and light therapy.Age-related macular degeneration, or AMD, is the No 1 cause of blindness among adults over 50 years in the U.S. Experts say one in three people will be affected by the disorder by the time they reach age 75, and it will assume epidemic proportions as the population ages.The disease is known to destroy a person's sharp central vision incapacitating him or her in doing daily chores, including recognition of faces. Nearly 90 per cent of the cases are a "dry" form of the disease, while wet, or neovascular, AMD, which accounts for the rest, is on account of abnormal blood vessel formation, resulting in fluid leakage and subsequent damage to the vision cells in the eye.The effectiveness of Lucentis in wet AMD has been corroborated in two new studies, which are reported in the New England Journal of Medicine. The drug secured the approval of the U.S. Food and Drug Administration in June. In the first study, Dr Philip J. Rosenfeld from the University of Miami and colleagues covered 716 patients who were randomly given either monthly injections of Lucentis (at a high or low doses) or placebo injections for two years. All of the patients had relatively early-stage disease. After one year, roughly 95 per cent of patients treated with either dose of Lucentis had no loss of vision compared with 62 per cent of the group given placebo injections. In addition, it was found that 25 per cent of patients treated with low dose Lucentis and 34 per cent treated with high dose experienced improvements in vision, compared with just 5 per cent of the other group. The benefits continued to be seen after two years. In the second study, carried out by Dr David M. Brown of the Methodist Hospital in Houston and colleagues 423 patients with wet AMD were treated either with Lucentis or with verteporfin for one year. It was found that about 95 per cent of the patients getting Lucentis lost no vision compared with 64 per cent undergoing the verteporfin therapy. In addition, vision improved in 36 to 40 per cent of those treated with Lucentis compared with 6 per cent in the other group. In both the studies, the doctors found that 1 per cent of patients treated with Lucentis had developed inner eye inflammation.Rosenfeld, who led the first study, clarified that Lucentis is not a cure for 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 belongs to a drug type known as a "recombinant, humanized monoclonal antibody." It works by neutralizing vascular endothelial growth factor, which is a naturally occurring molecule that helps fuel the formation of new blood vessels.Both the studies were sponsored by Genentech, which makes Lucentis, and Novartis Pharma, which markets the drug in the U.S. and abroad.A single dose of Lucentis costs about $2,000.Before the availability of Lucentis, doctors have been treating wet AMD patients with a cancer drug, called bevacizumab and sold as Avastin. Since the FDA has not approved it for treating AMD, doctors have been using it as an "off-label" drug. A single dose of Avastin costs around $550. Experts have, however, not come out saying for sure if Lucentis works better than Avastin. The U.S. National Eye Institute now plans to compare the two drugs under controlled conditions.