Metastatic colorectal cancer (mCRC) patients with mutant KRAS or NRAS are ineligible for anti-epidermal growth factor receptor (anti-EGFR) therapy, as RAS mutations activate downstream pathways independently of EGFR and induce primary resistance.
Adding cetuximab to FOLFIRI (5-fluorouracil, leucovorin, irinotecan) significantly improved progression-free survival (PFS), overall survival (OS), and objective response rate (ORR) in patients with KRAS or RAS (KRAS/NRAS, exons 2-4) wild-type (wt) metastatic colorectal cancer (mCRC) in the first-line CRYSTAL study.
Analysis of K- and N-RAS mutations is mandatory before planning treatment of metastatic colorectal cancer, because only RAS wild-type (WT) patients can benefit from treatment with anti-EGFR monoclonal antibodies (cetuximab and panitumumab).
Analysis of KRAS/NRAS Mutations in a Phase III Study of Panitumumab with FOLFIRI Compared with FOLFIRI Alone as Second-line Treatment for Metastatic Colorectal Cancer.
FIRE-3 evaluated first-line FOLFIRI plus cetuximab (FOLFIRI/Cet) versus FOLFIRI plus bevacizumab (FOLFIRI/Bev) in mCRC patients with RAS-WT tumour (i.e. wild-type in KRAS and NRAS exons 2-4).
Hence, ligand-dependent tumor suppressor signaling using therapeutic ephA2 agonists might offer new therapeutic opportunities to clinically widen the use of cetuximab in NRAS-mutated and/or ephA2-dependent mCRC tumors.
In 2014 the European Medicines Agency included exon 2, 3 and 4 KRAS and NRAS testing for the selection of metastatic colorectal cancer (mCRC) patients eligible for the therapy with anti-EGFR monoclonal antibodies.
International guidelines made RAS (KRAS and NRAS) status a prerequisite for the use of anti-EGFR agents for metastatic colorectal cancer (CRC) patients.
It remains unclear whether an anti-VEGF or anti-EGFR antibody with standard doublet chemotherapy is the optimal first-line treatment in patients with RAS (KRAS/NRAS) wild-type metastatic colorectal cancer (mCRC).
KRAS and NRAS mutations are identified resistance mutations to anti-epidermal growth factor receptor monoclonal antibodies in patients with metastatic colorectal cancer.
Meta-analysis suggests that mutations in KRAS exons 3 and 4, NRAS, BRAF and PIK3CA and non-functional PTEN predict resistance to anti-EGFR therapies and demonstrates that biomarker analysis beyond KRAS exon 2 should be implemented for prediction of clinical benefit from anti-EGFR antibodies in metastatic colorectal cancer.
PCO: All patients with mCRC who are candidates for anti-EGFR antibody therapy should have their tumor tested in a Clinical Laboratory Improvement Amendments-certified laboratory for mutations in both KRAS and NRAS exons 2 (codons 12 and 13), 3 (codons 59 and 61), and 4 (codons 117 and 146).
RAS (KRAS and NRAS) testing is required to predict anti-epidermal growth factor receptor (EGFR) treatment efficacy in metastatic colorectal cancer (CRC).
Recent studies have extended these findings by demonstrating that mutations in KRAS exons 3 and 4 and in NRAS exons 2, 3, and 4 (with all KRAS and NRAS mutations collectively referred to as RAS) are also predictive for treatment outcomes among patients with mCRC receiving panitumumab and cetuximab in combination with chemotherapy or as monotherapy.
The EWG encourages further studies of the potential value of testing in patients with mCRC who were found to have tumors that are wild type (mutation negative) for KRAS to predict responsiveness to therapy.The EWG found insufficient evidence to recommend for or against testing for mutations in NRAS, or PIK3CA, and/or loss of expression of PTEN or AKT proteins.
The first patient had metastatic colorectal cancer in which we identified somatic point mutations in NRAS, TP53, AURKA, FAS, and MYH11, plus amplification and overexpression of cyclin-dependent kinase 8 (CDK8).
The first-line FOLFIRI plus panitumumab was associated with favourable efficacy in the patients with wild-type KRAS and wild-type NRASmCRC, and it was well tolerated.