Experimental Cancer Drug Shrinks Tumors And Extends Survival


NewsRx.com


June 22, 2003

An experimental cancer drug named bevacizumab (trade name Avastin) is the first
"antiangiogenesis" drug to prove that it can shrink tumors and extend survival
in patients with metastatic colorectal cancer, according to a national clinical
trial led by researchers at the Duke Comprehensive Cancer Center.

Patients who received bevacizumab together with standard chemotherapy survived a
median of 5 months longer than patients who received standard chemotherapy
alone, the study showed. A 5-month life extension is quite significant, given
that patients with newly diagnosed colorectal cancer survive an average of 15-17
months, said Herbert Hurwitz, MD, lead investigator of the study and an
assistant professor of medicine at Duke University Medical Center.

Furthermore, the new study lends critical support to the long-debated approach
of choking off a tumor's blood supply in order to inhibit tumor growth, said
Hurwitz. This antiangiogenesis approach has been touted as a plausible strategy
against tumors but has never been proved successful in a large, randomized group
of patients - until now.

Hurwitz presented the results of the study, funded by Genentech, Inc., at the
annual meeting of the American Society of Clinical Oncology in Chicago.

"Our study offers important proof of the philosophy that targeting a tumor's
blood supply can, in fact, inhibit the tumor's ability to proliferate," said
Hurwitz. "Moreover, our current success will likely lead the cancer community to
conduct large-scale clinical testing of bevacizumab as a treatment for other
types of cancers."

In the current study, approximately 800 patients at various institutions
nationwide were randomly assigned to receive bevacizumab plus standard
chemotherapy (irinotecan, 5-FU, and leucovorin), or the standard chemotherapy
with placebo.

Patients who received bevacizumab plus chemotherapy survived a median of 20.3
months, compared to 15.6 months for patients who received standard chemotherapy
alone. Bevacizumab also delayed cancer progression for a median of 10.6 months
vs. 6.2 months for the standard chemotherapy. In addition, the bevacizumab and
chemotherapy combination shrank tumors by at least half in 45% of patients, vs.
35% in patients receiving standard chemotherapy alone.

"Metastatic colorectal cancer is a very aggressive disease, so we view these
results with real optimism, as we now have another weapon in the fight against
this cancer," said Hurwitz.

Bevacizumab works by inhibiting a protein called vascular endothelial growth
factor (VEGF), which is secreted by malignant tumors in order to grow and
maintain their blood vessels. When VEGF is blocked by bevacizumab, the tumor's
blood is diminished and the tumor shrinks and slows its spread.

Bevacizumab has fewer side effects than standard chemotherapy because it
selectively targets blood vessels within tumors, which secrete more VEGF than do
normal blood vessels in the body. The most frequent side effect was a moderate
elevation in blood pressure, which was easily managed by medications, the study
showed.

Hurwitz said that, while the bevacizumab results are very encouraging, the drug
represents one of many weapons in a battery of drugs designed to combat the
disease.

"Cancer is a very savvy opponent, and it often devises ways to circumvent our
current methods of inhibiting it," said Hurwitz. "In addition, each tumor has
its own characteristics that may cause it to behave differently from another
patient's tumor. For these reasons, no single therapy will work for every
patient, so it's important to develop multiple ways of combating the growth and
spread of cancer." This article was prepared by Angiogenesis Weekly editors from
staff and other reports.


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