The off-label usage of Avastin (bevacizumab) has become widespread as a treatment for age related macular degeneration. Developed as a treatment for cancer, the drug manufacturer, GenenTech has expressed concerns over the use of this drug to treat macular degeneration primarily because there has been no major study conducted to determine the safety of this drug for retinal treatments.
In order to develop Avastin into a safe and effective drug for wet macular degeneration, Genentech says that they would have to start at the pre-clinical trial stage. Considering the involvement of time (5-7 years), they maintain that such an effort would be fruitless when Lucentis is already in place and proving its value as a macular degeneration treatment. GenenTech has indicated that it does not plan on entering into a clinical trial to test Avastin as a treatment for macular degeneration.
Regarding the large cost difference between the two drugs, the company holds that it should not be a serious concern, as treatment is fully-accepted by insurance and Medicare. Genentech also has in place their “Access to Care” foundation to provide financial assistance to patients if needed. Genentech strongly states that their decision to not pursue Avastin as a macular degeneration treatment option is not financially-based. The cost of such research would be high, they say, but to invest so much time and money trying to prove the dubious theory that Avastin is as good as Lucentis would be counterproductive when there are more important areas that need attention. However, there have been threats by the United States Senate to investigate the company’s practices and pricing of the drug, especially after the company stated it would limit the availability of Avastin for retinal uses.
Despite concerns about Avastin, small studies and clinical observations have recently shown that intravitreal treatment with Avastin is showing no systemic adverse events and that the drug is showing success in inhibiting neovascularization and improving visual acuity in those patients with macular degeneration. Small studies have shown no difference in eyes treated with Avastin and eyes treated with the more expensive drug Lucentis.
Avastin works by inhibiting growth of abnormal blood vessels in the back inner part of the eye (retina), a condition that occurs in wet macular degeneration. Researchers at the University of Miami’s Bascom Palmer Eye Institute said Avastin substantially reduced blood vessel leakage contributing to vision loss. A larger study is needed to determine if benefits of Avastin as a macular degeneration therapy outweigh risks, said Philip J. Rosenfeld, MD, PhD, associate professor of ophthalmology at the Institute.
“A potential advantage of Avastin over other therapies for wet AMD is that vision improvement can occur within one week of treatment,” said Dr. Rosenfeld, the principal investigator of the Bascom Palmer clinical trial. “In addition to the improved vision, Avastin causes a reduction in leakage from the abnormal blood vessels, and we observed a restoration of normal macular anatomy.”
Dr. Rosenfeld went on to emphasize that Avastin therapy isn’t a cure and it’s not the right treatment for everyone with wet macular degeneration. Avastin is only for patients in the early stages of the disease and should be used within 6 months to 12 months from the time of onset, said Dr. Rosenfeld. Some people would rather have an injection in the eye than worry about the risks of a systemic drug. What this offers us is a new potential option for patients with wet AMD. It also provides us with additional evidence that VEGF is the major factor for blood vessel growth and vision loss in wet macular degeneration.
“We don’t know how many treatments will be needed,” Rosenfeld said. “In this study patients were treated two or three times over a twelve week period. As most patients commonly get wet macular degeneration in both eyes, an added advantage of this therapy is that both eyes can be treated with a single infusion into the arm. [Avastin is now delivered as an intraocular injection.] A larger clinical trial is needed to determine if the benefits of Avastin outweigh the risks.
Avastin will continue to be used as a treatment for macular degeneration until the cost of Lucentis become reasonable.