wt-KRAS as Erbitux efficacy biomarker

German drugmaker Merck KGaA says that data from three studies of the anticancer agent Erbitux (cetuximab) indicate that it is more effective in metastatic colorectal cancer patients suffering from the wild-type KRAS tumor variant than in those with other forms of the disease. The firm added that the wt version of the gene is found in around 65% of all mCRC cancers.

The KRAS gene, in common with other members of the Ras family, can function as a cancer-promoting onco-gene capable of activating proteins responsible for tumor-proliferation. Since KRAS is involved in the production of the epidermal growth factor receptor (EGRF), the molecule targeted by Erbitux, aberrant gene functioning due to mutation, can reduce the efficacy of treatment through the production of malformed EGRF molecules with which Erbitux can no longer bind.

Patients with wt KRAS show improved RR