The widely used cancer drug Avastin could save the eyesight of
tens of thousands of people with age-related macular degeneration
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 health care 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.
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 percent
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 part of their eye, which is the most important part 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 with $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 percent of the patients receiving
Avastin had a significant improvement in vision, compared with only
3 percent 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, Northern Ireland, said the
trial shows that Avastin is better than the treatments it was
compared with, but cautioned that wider use should be limited until
the results become available from the head-to-head trial with
Lucentis.
Dr. Adnan Tufail and his colleagues, who conducted the study,
argued, though, that the vision of many patients in underdeveloped
countries could be saved with Avastin while researchers are
awaiting results of that trial.
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