May 23, 2000 (New Orleans) -- An experimental drug that prevents the formation of new blood vessels seems to help people with advanced lung and colon cancer live longer by depriving tumors of the blood and oxygen they need to grow. Two studies of the drug, called rhuMAb-VEGF, were reported here at an annual meeting of the world's leading cancer clinicians and researchers. The unexpected deaths of four lung cancer patients in one study indicate that certain cancer patients should not receive the treatment.
The lung cancer patients with disease that had spread outside the lung, or metastasized, who received a high dose of rhuMAb-VEGF plus chemotherapy lived twice as long as those who received either a low dose of rhuMAb-VEGF plus chemotherapy or chemotherapy alone.
"I am personally very encouraged by these results and believe rhuMAb-VEGF should be tested in patients with earlier stage disease, as well as in other types of cancers," study author Russell DeVore, MD, tells WebMD. At the time of the study, DeVore was director of thoracic oncology at Vanderbilt University in Nashville.
VEGF, or vascular endothelial growth factor, is a chemical that is produced by tumors to increase their blood supply, allowing it to grow even further. It does this by increasing the number of blood vessels in and around the tumor. A great deal of medical research has focused on medications, like rhuMAb-VEGF, that block the effects of VEGF and similar chemicals. Cancer researchers have hoped that by blocking VEGF and adding chemotherapy, they could shrink tumors.
DeVore and colleagues studied almost 100 patients with metastatic non-small cell lung cancer, the most common type of lung cancer. They tested rhuMAb-VEGF at two doses in combination with chemotherapy and chemotherapy alone.
"Although the drug was mostly well-tolerated, six patients on rhuMAb-VEGF developed bleeding in their lungs, and four of them died," DeVore says. "We think we can identify those patients at risk of bleeding beforehand and use other forms of treatment."
In a second study, researchers tested rhuMAb-VEGF in patients with metastatic colon cancer. More than 100 patients were studied, and they received one of three treatments: chemotherapy alone, or chemotherapy in combination with either a high-dose or a low-dose of rhuMAb-VEGF.
In the colon cancer patients who received the lower dose of rhuMAb-VEGF plus chemotherapy, cancer relapse was slowed, study author Emily Bergsland, MD, tells WebMD. The disease did not recur for 9 months after the patients were treated. This was longer than what was seen in the other two groups, where the patients who received chemotherapy and the higher dose of rhuMAb-VEGF had a recurrence of their cancer seven months later, and those who received only chemotherapy experienced recurrence five months later. Bergsland is a clinical assistant professor of medicine at the University of California at San Francisco.
Richard Schilsky, MD, professor of medicine at the University of Chicago, commented on the studies for WebMD. "I think all of us believe if these types of molecules are going to work, they're going to work in patients with earlier disease," he says. "Studies like these need to be done to quickly show an effect, but I don't think they're going to provide any real benefit."
Says Schilsky, "Some studies indicate that tumors are forming new blood vessels much earlier in their development than the tumors in these studies, so using something to block the formation of new blood vessels would work better then. These studies are beginning to be undertaken now."