Erbitux Gets Response with Colorectal Cancer Biomarker

ImClone Systems’ data from the Phase II OPUS study show that the addition of Erbitux to Folfox chemotherapy significantly improves both response rate and progression-free survival over Folfox alone in the first-line treatment of metastatic colorectal cancer (mCRC) patients whose tumors do not have mutations of the K-Ras oncogene (K-Ras wild-type).
   
The randomized first-line Phase II study of 337 patients compared Erbitux plus Folfox to Folfox alone in epidermal growth factor receptor (EGFR)-expressing mCRC patients who have not previously been treated. Oxaliplatin-based chemotherapy regimens, including Folfox, are used in the majority of first-line colorectal cancer patients in the U.S. The study’s primary endpoint was response rate, which was found to be 46% in the Erbitux-plus-Folfox arm compared with 36% in the Folfox-only arm. When the wild type K-Ras patients are selected from the population, the response rate in this group increased to 61% in the Erbitux-plus-Folfox arm compared with 37% in the Folfox-only arm. With the progression-free survival endpoint, the risk of disease progression was reduced by 43% by the addition of Erbitux to Folfox chemotherapy in wild-type K-Ras patients.  
   
In several recent clinical studies, screening patients for the K-Ras biomarker has been shown to be a highly effective tool in determining which patients will respond better to a particular cancer therapy. The non-mutated, or “wild type,” K-Ras gene is expressed in about 65% of mCRC patients.