Extended RAS Mutation Testing in Colorectal Cancer Predicts EGFR MoAb Response

Treatment with anti-epidermal growth factor receptor (EGFR) monoclonal antiboday (MoAb) should only be considered in patients with metastatic colorectal cancer (mCRC) whose tumors lack RAS mutations, according to an American Society of Clinical Oncology Provisional Clinical Opinion update.¹

Recent phase 2 and 3 trials have indicated that patients with mCRC whose tumors harbor the RAS mutations in exons 2 (codons 12 and 13), 3 (codons 59 and 61), and 3 (codons 117 and 146) are not likely to benefit from treatment with EGFR MoAbs when used as monotherapy or combination therapy.

Given these results, researchers analyzed 11 systematic reviews with meta-analysis, two retrospective analyses, and two health technology assessments based on a systematic review.

Outcomes for patients with mCRC with no mutation detected or presence of mutation in additional exons in KRAS and NRAS were evaluated.

Researchers concluded that all patients with mCRC who are candidates for therapy with EGFR MoAbs should have their tumor tested in a Clinical Laboriatory Improvement Amendments-certified laboratory for KRAS and NRAS mutations.

Reference

1. Allegra CJ, Rumble BR, Hamilton SR, et al. Extended RAS gene mutation testing in metastatic colorectal carcinoma to predict response to anti-epidermal growth factor receptor monoclonal antibody therapy: American Society of Clinical Oncology Provisional Clinical Opinion Update 2015. [published online ahead of print on October 5, 2015]. J Clin Oncol. doi: 10.1200/JCO.2015.63.9674.