Clinical photo courtesy of Jacque Duncan, MD, UCSF Department of Ophthalmology
This week, the second-year results of an important clinical trial on age-related macular degeneration (AMD), known as the Comparison of AMD Treatments Trials (or CATT), were published in the journal Ophthalmology. Researchers found that two drugs known as Avastin (bevacizumab) and Lucentis (ranibizumab), commonly used to treat the wet form of AMD, were similarly effective in maintaining vision.
In this clinical trial funded by the National Eye Institute (NEI) of the National Institutes of Health, CATT researchers found that two years into the study, two-thirds of patients retained a vision of 20/40 or better, whereas only 15% of patients retained similar vision with previous treatments.
“As a nonprofit organization that funds groundbreaking research and provides public information on AMD, the BrightFocus Foundation welcomes discoveries from the CATT trials on wet AMD, which affects two million Americans,” says BrightFocus Vice President for Scientific Affairs, Guy Eakin, Ph.D. “We also call for more support of research on this and other eye diseases. In the future, our goals are not just to maintain vision, but to restore vision and ultimately to prevent the disease entirely.”
For both drugs, vision was slightly better with monthly injections, rather than with less frequent or “as-needed” injections. However, study authors were also quick to note that since as-needed dosing requires fewer drug injections into the eye, some patients, following consultation with their eye doctor, may elect not to choose monthly injections, balancing relative risks and cost.
“While this study neither adds nor removes the number of drug choices available to the eye care provider, it does facilitate better informed decision making between the doctor and patient,” says Eakin. He notes the findings of study authors, who conclude, “The choice of drug and dosing regimen for patients must balance the comparable effects on vision, the possibility of true differences in adverse events, and the 40-fold difference in cost between [Lucentis and Avastin].”
AMD is the leading cause of irreversible central vision loss in people older than age 60. The disease affects the central area of the retina known as the macula, and, without treatment, gradually destroys the central vision needed to conduct many activities of daily living. Although vision loss from AMD cannot be reversed at present, early detection and treatment can halt the progression of the disease.
In the wet form of AMD, Avastin and Lucentis, two therapies known as angiogenesis inhibitors, block the growth of abnormal blood vessels and fluid leakages that damage the eye. Lucentis was approved for AMD treatment by the FDA in 2006; Avastin is approved for other purposes but has been used “off-label” to treat AMD. Both are manufactured by Genentech, and Lucentis is significantly more expensive that Avastin.
“AMD patients should note that serious adverse events—involving the development or worsening of medical conditions—occurred at a 40% rate for Avastin and a 32% rate for Lucentis,” adds Eakin. “However, the study authors note that CATT was not capable of determining whether there was an association between a particular adverse event and treatment. The median age of CATT patients was older than 80, and certain medical conditions are more common to elderly populations. AMD patients should discuss the risk of adverse events with their eye doctor.”
“While we welcome the latest information from the CATT study, BrightFocus urges even more public and privately funded research on AMD,” notes Eakin. “This is particularly true for the more common dry form of AMD affecting nine million Americans, for which there are no approved treatment options at present.”
The drugs reviewed in the CATT study focus only on the growth of blood vessels in the wet form of the disease. Says Eakin, “We need to target other aspects of the disease, like inflammation and protection of neurons. We also need a stronger national commitment to funding eye research and to improving the lives of people affected by or vulnerable to AMD and other blinding eye diseases.”