Phase III analysis of Erbitux for Colorectal Cancer confirms earlier studies-Merck KGaA

Merck KGaA has announced new findings from a retrospective analysis of the completed Phase III study CRYSTAL that compared Erbitux (cetuximab) plus FOLFIRI with FOLFIRI alone in patients with KRAS wild-type (exon 2) metastatic Colorectal Cancer (mCRC). A significant clinical improvement was observed in patients with RAS wild-type tumors when Erbitux was added to FOLFIRI in firstline mCRC. The analysis shows a 27.7% increase in response rate (RR), a 3.0-month increase in median progression-free survival (PFS), and an 8.2-month increase in median overall survival (OS) in mCRC patients with RAS wild-type tumors (n=367) receiving firstline Erbitux plus FOLFIRI, compared with patients receiving FOLFIRI alone.

In the patient group with either KRAS exon 2 mutations identified in the initial KRAS analysis (n=397) or other RAS mutations (n=63) receiving Erbitux plus FOLFIRI (n=246) no benefit was observed, compared with FOLFIRI alone (n=214) (RR: 31.7% vs. 36.0%, respectively. This subgroup analysis confirms the findings of OPUS and other studies which have shown that patients with RAS mutations do not benefit from anti-EGFR therapy. The new data will be presented at the 2014 American Society of Clinical Oncology (ASCO) Annual Meeting.