Personal Injury Law

Targeting Colon Cancer With Gene Test

By Jane Akre

A new study on colon cancer may help doctors pinpoint who will benefit from the drug, Erbitux (Cetuximab).

Erbitux is most effective in colon cancer patients who lack a particular genetic mutation in their tumor. A study of nearly 600 patients was presented Sunday at the American Society of Clinical Oncology.

About two-thirds of colon cancer patients do not have the mutated gene called KRAS and are the best candidates for Erbitux.   That means about 36 percent of patients will not see an improvement with Erbitux, and likely will be treated instead with Avastin, made by Genentech and Roche. 

Of the patients studied, all had colorectal cancer that had spread. 

About 60 percent of the patients without the mutation had their tumor shrink by half with Erbitux. Patients taking FOLFIRI, which is a drug combination, saw their tumors shrink by 43 percent.

Erbitux costs about $5,000 for two weeks worth. A similar drug, Vectibix costs $4,000 but also appears to work only in those without the KRAS mutation.

The gene mutation can be tested for at a cost of $500 to $1,000. 

The study comes out of the University Hospital Gasthuisberg in Leuven, Belgium and was presented Sunday in Atlanta.    

Professor  Dr. Eric van Cutsem, tells  the Washington Post, "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."

"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 told the Washington Post.  

Colorectal cancer is the third most common cancer with a mortality rate that is decreasing, according to government statistics. Americans have about a one in 20 lifetime risk of developing colorectal cancer and it affects primarily those over age 65, but the risk increases beginning at age 40. 

According to the National Cancer Institute, the cause is unknown but there are at least eight different genes involved that can be traced to animal fat. When fat is metabolized, bacteria in the bowel form carcinogens that can irritate the intestinal lining, which may form polyps, often a precursor of cancer.  Less animal fat and higher fiber in the diet are thought to be somewhat protective.  

Erbitux, made by Bristol-Myers Squibb and ImClone Systems Incorporated,was approved two years ago. Side effects include an acne-like rash, stomach pain, fever, and feeling tired.  

Shares of ImClone fell before the bell opened Monday as analysts say the study will cut Erbitix use by about 15 percent. # 

Full post as published by InjuryBoard on June 02, 2008 (boomark / email).