The widely used cancer drug Avastin could save the eyesight of tens of thousands of people with age-related macular degeneration (AMD) of the wet form, British researchers said Friday. The drug provides an inexpensive alternative to the only drug currently licensed for treating the disorder, they found, and should be used immediately in countries with limited healthcare budgets, the researchers reported online in the journal Lancet. Avastin, known generically as bevacizumab, is already used by many physicians to treat AMD, but there has been little evidence from clinical trials to support its efficacy.
[Updated at 3:10 PM. The study was actually reported online in the journal BMJ.]
Avastin is a monoclonal antibody that targets a hormone, vascular endothelial growth factor, that stimulates the growth of blood vessels that nurture tumors. It is already used for treating bowel and lung cancer, and studies reported earlier this week show that it is also effective at keeping ovarian cancer in check. It is not licensed for treating AMD, but many physicians use it "off-label" to treat the disorder, a perfectly legal alternative.
AMD affects about 1.25 million Americans. Only about 15% of them have the wet form, which results from bleeding into the eye that impairs vision, but vision loss is far more severe with wet AMD than with the dry form. Victims of the disorder lose sight in the central portion of their eye, which is the most important portion for reading and other activities.
Roche, which manufactures Avastin, also produces a similar drug called Lucentis (known generically as ranibizumab) that is licensed to treat AMD. But the small amount of Avastin needed to treat AMD costs only about $50, compared to $1,950 for Lucentis, and some countries have not agreed to pay for the new drug because of its high cost. The U.S. National Eye Institute is now conducting a clinical trial comparing the two drugs head-to-head for treating AMD, but results from that study are not expected until the middle of next year.
Dr. Adnan Tufail of the Moorfields Eye Hospital in London and his colleagues began their study of Avastin before Lucentis was available in Britain. They enrolled 131 patients with wet AMD who were at least 50 years old. The patients were randomized to receive either injections of Avastin every six weeks or the best available medical therapy.
At the end of a year, 32% of the patients receiving Avastin had a significant improvement in vision, compared to only 3% of those in the standard care group. In contrast, those given standard care were significantly more likely to lose vision over the course of the study, the researchers found.
In an editorial accompanying the report, Dr. Usha Chakravarthy of the Royal Victoria Hospital in Belfast, Ireland, said that the trial robustly shows that Avastin is better than the treatments it was compared to, but cautioned that wider use should be limited until the results become available from the head-to-head trial with Lucentis. Tufail and his colleagues, however, argued that the vision of many patients in underdeveloped countries could be saved with Avastin while researchers are awaiting the results of that trial.
-- Thomas H. Maugh II