Erbitux Works Well for Two-Thirds of Colon Cancer Patients

By Amanda Gardner
HealthDay Reporter
Monday, June 2, 2008; 3:00 AM

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SUNDAY, June 1 (HealthDay News) -- Colon cancer patients who have the normal version of a particular gene are more likely to benefit from a combination treatment that includes adding the targeted therapy Erbitux to chemotherapy.

Some two-thirds of colon cancer patients have the normal, or "wild-type" form of the gene, according to the new study.

"These findings are very important for patients and also for clinicians, as we have shown that, using this KRAS test, we can predict which patients will benefit and which will not benefit from cetuximab [Erbitux]," said study author Dr. Eric van Cutsem, a professor at University Hospital Gasthuisberg in Leuven, Belgium. "We have shown that the activity of cetuximab is confined to the patients with the KRAS wild-type tumor so, if we know in advance that a patient has the mutation, we know that we don't have to treat them with cetuximab."

Van Cutsem spoke at a news conference Sunday at the American Society of Clinical Oncology in Chicago, where he also presented his results.

The test is already widely available. Last week, European authorities approved adding Erbitux to chemotherapy but only in patients with the normal version of the gene, van Cutsem said.

"We're moving towards tailored or personalized therapy for patients," said Dr. John Kauh, an assistant professor of hematology and medical oncology at Emory's Winship Cancer Institute in Atlanta. "We've always known that tumors are highly heterogeneous. We are now just beginning to see with the data that we can basically take a patient's tumor, test it, and see if Patient A should get cetuximab and whether Patient B should not, and maybe, for that patient, it may be better."

Earlier results from the same trial presented at last year's meeting found a 15 percent reduction in risk in patients treated with the combination therapy as opposed to chemotherapy alone.

Since that time, the biology of KRAS has become better understood, and other studies have shown the value of the combination treatment as a third-line treatment. "Those with the KRAS mutation were resistant to cetuximab in third-line treatment," van Cutsem said.