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 ovarian tumors.
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 WebMD.
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 kidney cancer.
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 interferon alone.
“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 drug axitinib.
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.