New England Journal of Medicine, NEJM, III CRYSTALa trial confirm, the enhanced efficacy of Erbitux (cetuximab) in combination with standard irinotecan-based chemotherapy (FOLFIRI) in metastatic colorectal cancer (mCRC) patients compared to chemotherapy alone. Patients with KRAS wild-type tumours receiving Erbitux benefited from significantly increased tumour response rates of up to 59 per cent [p=0.0025] and a 32 per cent decrease in the risk of disease progression compared to patients receiving FOLFIRI alone [Hazard Ratio (HR)=0.68; p=0.02].1,2

"These results are an important advance in the 1st-line treatment of mCRC and clearly demonstrate the benefit of selecting the appropriate treatment for patients, based on the KRAS status of their tumour, before treatment begins," commented professor Eric Van Cutsem, lead investigator of the CRYSTAL study and Professor of Medicine and Digestive Oncology from the University Hospital Gasthuisberg in Leuven, Belgium. "The response rates are particularly exciting - by shrinking tumours we can relieve patients from discomfort or symptoms or, in other cases, shrink tumours sufficiently to allow them to be surgically removed, which provides the potential for cure. These findings suggest Erbitux should be considered an important new option in this setting."

CRYSTAL was a multi-center, phase-III, randomized, controlled trial involving 1,198 patients that investigated the efficacy and safety of Erbitux in combination with FOLFIRI vs. FOLFIRI alone in the 1st-line treatment of patients with mCRC.1 KRAS mutation status was included within the analysis and tumour samples from 540 patients were analyzed. The KRAS-evaluable population was found to be representative of the overall study population and 64.4 per cent of these patients tested KRAS wild-type.

"These impressive results from CRYSTAL, demonstrating high response rates of nearly 60 per cent in KRAS wild-type patients, clearly support the use of Erbitux in the 1st-line setting," noted Dr Wolfgang Wein, executive vice president, Oncology, Merck Serono. "This is a landmark trial supporting the introduction of biomarkers for tailored therapy in patients with mCRC."

The efficacy of Erbitux in combination with standard oxaliplatin-based chemotherapy (eg FOLFOX-4) as 1st-line mCRC therapy has also been established as evidenced by data from the OPUSb study recently published in the Journal of Clinical Oncology. The results of the CRYSTAL and OPUS trials supported the recently approved license extension of Erbitux in Europe, which is now approved for use in combination with chemotherapy in all lines of treatment of patients with EGFR-expressing, KRAS wild-type mCRC, and also as a single agent in patients who have failed oxaliplatin- and irinotecan-based therapy and who are intolerant to irinotecan.

Erbitux is a first-in-class and highly active IgG1 monoclonal antibody targeting the epidermal growth factor receptor (EGFR).