Drugs equally effective for age-related vision loss
A two-year comparison showed that the drugs Avastin and Lucentis lead to similar vision improvements in patients with age-related macular degeneration (AMD). The study also found that visual gains were slightly better with monthly rather than as-needed treatments.
AMD is the leading cause of vision loss and blindness in older Americans. The condition affects the macula, the central portion of the retina that allows us to look straight ahead and see detailed images. In its advanced stages, AMD can trigger growth of abnormal blood vessels that leak fluid and blood into the macula, damaging the macula and obscuring central vision. Without treatment, most patients with this "wet" form of AMD lose their ability to drive, read, recognize faces or perform certain tasks.
In 2006, the U.S. Food and Drug Administration (FDA) approved the use of Lucentis (ranibizumab) for treating AMD. By that time, some ophthalmologists had already begun treating AMD with a similar drug-the cancer medication Avastin (bevacizumab)-although it hadn't been FDA-approved for that purpose. Both drugs are injected directly into the eye, and both are now widely used to treat AMD. But doctors didn't know which drug might be more effective or what dosing schedule might be best.
In 2008, NIH's National Eye Institute (NEI) launched a 2-year clinical trial to compare the two drugs. The study, called the Comparison of AMD Treatments Trials (CATT), published its first-year results in May 2011. That initial report found that both drugs were equally effective in preventing vision loss from AMD. The new report describes the findings from the trial's second year. It appeared in the April 30, 2012, online edition of Ophthalmology.
At enrollment, about 1,200 patients with AMD were randomly divided into four treatment groups. The groups were defined by drug (Avastin or Lucentis) and dosing regimen (monthly or as-needed). After the first year, patients on monthly dosing were randomly reassigned to monthly or as-needed regimens. All continued to receive their initial drug.
By year two, the researchers found that both drugs led to similar improvements to vision. At least 60 percent of patients in all groups achieved 20/40 vision or better-the level needed for driving. In contrast, earlier research showed that less than 15 percent of AMD patients receiving previously available treatments could attain that level of visual accuracy.
The study found slightly less vision gain with as-needed than with monthly dosing, regardless of the drug. As measured on an eye chart, monthly treatment resulted in a mean improvement of about half a line better than as-needed dosing. Switching to as-needed treatment after a year of monthly dosing led to outcomes nearly equal to those obtained with two full years of as-needed treatment.
"Both drugs were highly effective regardless of the approach to dosing. There was slightly less vision gain with as-needed treatment," says CATT study chair Dr. Daniel F. Martin of the Cleveland Clinic. "Patients seeking the small extra advantage of monthly treatment need to be mindful of the additional burden, risks and costs of monthly injections. Since as-needed dosing required 10 fewer eye injections over the course of 2 years and yielded similar visual results, many patients may choose this option."
--From the National Institute of Health
For further information on this and other health topics, visit the web site of the National Institute of Health at www.nih.gov.