(Ivanhoe Newswire) -- A promising drug for treatment of colorectal cancer may not be effective in 40 percent of patients with the cancer, new research shows.
Analysis of a recent study shows when given the drug cetuximab (Erbitux), metastatic colorectal cancer patients with tumors showing the "normal" type of a gene called K-ras survived longer whereas those with a mutated form of the gene did not. More specifically, patients with normal K-ras tumors who received cetuximab showed an almost two-fold improvement in overall survival and progression-free survival compared to similar patients who received supportive care alone. Those with mutated K-ras tumors who received the drug showed no significant improvement compared to similar patients who received supportive care alone.
"These results provide critical insight as we progress toward fully understanding the role of K-ras as a predictive biomarker in the treatment of patients with advanced colon cancer," Christos Karapetis, M.D., the study's lead investigator from Flinders Medical Centre and Flinders University in Adelaide, Australia, was quoted as saying.
About 60 percent of patients with colorectal cancer are classified as saving wild-type, or "normal," K-ras status and the remaining 40 percent as having a mutated K-ras gene.
Previous studies have shown cetuximab slows the growth and survival of tumor cells that express the epidermal growth factor receptor.
SOURCE: New England Journal of Medicine, 2008;359:1757-1765
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