Tag Archives: KRAS

Colorectal Cancer News in Brief: April 10

This week we review research on the impacts of colonoscopy screening in Germany, folic acid flour supplementation in Chile, and untreated anxiety and pain during the last months of life on surviving spouses of cancer patients. In the news are reports of colon cancer surgery using a tiny incision in the belly button, requirements for KRAS testing before insurance will pay for Erbitux or Vectibix treatment, and information about how stem cells in the intestinal tract become cancer stem cells, driving the development and progression of colorectal cancer.

KRAS Testing Has Potential to Save Millions in Health Care Costs

Update from the 2009 Gastrointestinal Cancer Symposium Over half a billion dollars could potentially be saved if all patients with colorectal cancer that had spread were tested for the KRAS gene before beginning treatment. Because patients with mutated KRAS in their tumors don’t benefit from treatment with EGFR inhibitors Erbitux® (cetuximab) and Vectibix™ (panitumumab), offering them those drugs is a futile expense.  In addition, trying the drugs delays potentially effective treatment and exposes patients to skin rash and other unnecessary side effects.

NCCN Updates Guidelines to Include KRAS Testing

The National Comprehensive Cancer Network (NCCN) has updated their Clinical Practice Guidelines in Oncology for Colon Cancer to include testing tumors from patients with metastatic colon cancer for the KRAS gene.  The Guidelines also now say that cetuximab (Erbitux®) and panitumumab (Vectibix™) should only be given to patients whose tumors have normal (wild-type) KRAS.

Another Gene Found Linked to Lack of Erbitux/Vectibix Response

Another mutated gene has been discovered that appears to cause resistance to treatment with the EGFR inhibitors Erbitux® (cetuximab) and  Vectibix™ (panitumumab). Only a fraction of patients who receive Erbitux or Vectibix respond to it.  There is now convincing evidence that the 30 to 40 percent of colorectal cancer patients whose tumors have mutated KRAS genes don’t benefit, but what about others who have normal or wild-type KRAS and don’t respond either? Scientists in Italy have found that about 12 percent of wild-type patients have a mutation in their tumor’s BRAF gene, and these patients showed no response to Erbitux or Vectibix.

KRAS Status Doesn't Impact Treatment with 5-FU Alone

While researchers have found that colorectal cancer tumors that have mutated KRAS genes don’t respond to treatment with EFGR inhibitors Erbitux®(cetuximab) and Vectibix™(panitumumab), is the same thing true for other drugs? 5-FU (fluorouracil) is the backbone of most colorectal cancer treatment, given alone or in combination with other drugs.  What does KRAS status mean when 5-FU is the only treatment?

KRAS Mutation Status Predicts Response to Erbitux in Canadian Study

Another study has shown that colon or rectal cancer patients whose tumors have mutated KRAS don’t benefit from Erbitux® (cetuximab).  However, in the study when only patients with normal or wild-type KRAS were considered, survival time almost doubled after treatment with Erbitux began.

Avastin Benefits Not Affected by KRAS Mutations

Colorectal cancer patients with a KRAS mutation in their tumors benefit when Avastin® (bevacizumab) is added to chemotherapy, as do patients with no mutation or wild-type KRAS. Both the time until cancer got worse (progression-free survival) and time patients lived after beginning treatment (survival) were better when Avastin was added to chemotherapy regardless of tumor KRAS mutation.  Avastin did not improve overall response rates in the patients with KRAS mutations. However, overall prognosis is worse for patients with KRAS mutations than those with wild-type KRAS with either chemotherapy alone or chemotherapy with Avastin.  As a group, they tend to live for a shorter time and have their tumors progress more

KRAS Mutations Make a Difference In Response to Erbitux

Update from 2008 ASCO Meeting in Chicago Three studies reported during the 2008 American Society of Clinical Oncology found that colorectal cancer patients whose tumors have mutated KRAS genes do not benefit from treatment with the EGFR-inhibitor Erbitux® (cetuximab). At the same time, patients with tumors that aren’t aren’t mutated (wild-type) have significantly better results when Erbitux is added to either FOLFIRI or FOLFOX chemotherapy. Two randomized trials of initial treatment of chemotherapy with or without Erbitux found responses and improved progression-free survival only in patients with wild-type KRAS. The CRYSTAL Phase III study compared FOLFIRI to FOLFIRI with the addition of cetuximab. The Phase II OPUS trial used FOLFOX

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