Novel Cancer Drugs Target Tumor Roots
Agents Show Promise for Advanced Kidney, Thyroid, Ovarian Cancers
June 4, 2007 (Chicago) -- Anticancer drugs that starve tumors of their blood
supply are showing promise for the treatment of advanced kidney, thyroid, and
The drugs block the action of a substance released by tumors called vascular
endothelial growth factor, or VEGF. VEGF binds to certain cells to stimulate
new blood vessel formation.
“These are promising targeted therapies that kill cancer cells while leaving
healthy cells intact,” says Dean Bajorin, MD, a cancer doctor at Memorial
Sloan-Kettering Cancer Center in New York.
“They work by curbing the growth of new blood vessels to tumors,” thereby
depriving them of the nutrient-rich blood they need to grow, he tells
Bajorin moderated a news conference at which the new research was discussed
here at the annual meeting of the American Society of Clinical Oncology.
Avastin Fights Kidney Cancer
The first study showed that Avastin, already approved for use in fighting
colon and lung cancer, can also help delay progression in people with advanced
The study included 649 people who had surgery to remove their tumors. Those
who took Avastin in addition to standard interferon treatment remained alive
without worsening of their disease nearly twice as long as those given
“Adding Avastin resulted in a striking improvement” in the time it started
for the cancer to grow, slowing it from 5.4 months to 10.2 months, says
researcher Bernard Escudier, MD, head of the immunotherapy unit at the Gustave
Roussy Institute in Villejuif, France.
Also, tumors shrank or stopped growing in 31% of patients taking Avastin vs.
12% of those on interferon alone.
The most common side effects were fatigue and weakness.
Avastin was the first of the new kind of cancer therapies that work by
cutting off the blood to a tumor from the growth of new blood vessels -- a
process called angiogenesis.
Experimental Agent Combats Thyroid Tumors
In a second study, tumors shrank or stopped growing in nearly three-fourths
of people with advanced thyroid cancer given the experimental anti-angiogenesis
The study included 60 people given an axitinib pill twice a day. More than
18 months after the study began, nearly two-thirds of them are still alive
without evidence of progressive disease, says researcher Ezra Cohen, MD,
assistant professor of medicine at the University of Chicago.
Though there was no comparison group in the study, “the natural history of
the disease is such that a far greater percentage would have progressed had
they not been given axitinib,” Cohen says.
Cohen says standard treatment for the 30,000 Americans who develop thyroid
cancer is surgery or radiation therapy. Though this cures a large percentage of
patients, there are few options for those who do not respond, he tells
“Axitinib and other VEGF inhibitors represent an exciting new front in the
treatment of advanced thyroid cancer,” he says. “As recently as three years ago
we had very little to offer these patients, and now we’re seeing response rates
at a level we’ve never seen with chemotherapy.”