All-RAS-Mutation Testing for Anti-EGFR Therapy

Prior studies have shown that combining the epidermal growth factor receptor (EGFR)-targeted agents cetuximab and panitumumab with chemotherapy improved outcomes in patients with RAS wild-type metastatic colorectal cancer (mCRC). Investigators now report updated results of the CRYSTAL study (J Clin Oncol 2011; 29:2011), an industry-sponsored, international phase III trial comparing fluorouracil, leucovorin, and irinotecan (FOLFIRI) chemotherapy with or without cetuximab in patients with KRAS wild-type mCRC. In the current study, the authors expanded the analysis to test for other RAS mutations, including KRAS mutations in other exons and NRAS mutations.

Among the 666 CRYSTAL patients with KRAS exon 2 wild-type tumors, 430 (65%) were evaluabl…