The findings are similar to those of another trial reported this month, called AVANT, that found Avastin did not help stage 3 colon cancer patients.
"There's no evidence to suggest that this drug should be given in the adjuvant setting," said Dr. Frank Sinicrope, a professor of medicine and oncology at the Mayo Clinic in Rochester, Minn.
Avastin is one of a group of newer, so-called "targeted" cancer drugs -- meaning they interfere with specific proteins that help cancer cells grow and spread. Avastin blocks the formation of blood vessels that feed a tumor's growth and spread. Added to chemotherapy drugs -- which fight tumor cells directly -- Avastin can prolong the lives of people with advanced colon cancer.
No one knows for sure why the drug doesn't benefit people with earlier-stage colon cancer. But Allegra said the same situation has been seen with another "targeted" cancer drug: Erbitux (cetuximab).
He also said the experience with that medication, and now Avastin, raises questions about how drugs for stage 2 and 3 colon cancer are developed.
The current "paradigm," Allegra said, is to first test new drugs in patients with metastatic colon cancer. Only if the drugs show benefit in those trials are they moved to studies of patients with earlier-stage colon cancer.
Mayo's Sinicrope noted that in the past, that's worked.
Often, he said, chemotherapy drugs that have worked for metastatic colon cancer have turned out to work for earlier-stage disease, too. But that has not been the case when it comes to the targeted therapies like Erbitux and Avastin.
"We can't just grab the drug that works in the metastatic setting and cross our fingers that it will work in the adjuvant setting," Sinicrope said.
For patients with colon cance
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