The main objective of this trial is to explore the effect of combining an established chemotherapy regimen (FLOX), based on 5-fluorouracil, folinic acid, and oxaliplatin (Eloxatin®), with the EGF receptor antibody cetuximab (Erbitux®) in first-line treatment of metastatic colorectal cancer. The trial will investigate two regimens of FLOX plus cetuximab, in which FLOX is given continuously or intermittently, compared to standard FLOX without cetuximab.

Inclusion Criteria:

Histology and staging disease:

• Histological proven adenocarcinoma of the colon or rectum;
• At least one measurable metastatic disease
• If only one metastatic lesion and no S-CEA elevation, histology is mandatory;
• Availability of tumour sample for EGFR assessment.

General conditions:

• Age >18 and < 75 years;
• WHO performance status: life expectancy of more than 3 months;
• Adequate haematological function
• Adequate renal and hepatic functions
• Written informed consent

Exclusion Criteria:

Prior therapy:

• No prior chemotherapy for advanced/metastatic disease;
• No adjuvant chemotherapy the last 6 months before inclusion;
• No previous oxaliplatin;

Prior or current history:

• No current indication for resection with a curative intent;
• No evidence of CNS metastasis;
• No current infection, unresolved bowel obstruction or subobstruction, uncontrolled Crohn's disease or ulcerative colitis;
• No current history of chronic diarrhoea;
• No peripheral neuropathy;
• No other serious illness or medical conditions (including contraindication to 5 FU e.g.: angor, myocardial infarction within 6 months, contraindications to monoclonal antibodies);
• No past or concurrent history of malignant neoplasm other than colorectal adenocarcinoma within the past five years, except curatively treated non melanoma skin cancer or in situ carcinoma of the cervix;

Concomitant treatments:

• No concomitant (or within 4 weeks before randomisation) administration of any other experimental drug under investigation;
• No concurrent treatment with any other anti-cancer therapy;

Other:

• Not pregnant, no breast feeding
• Fertile patients must use adequate contraceptives
• Not include patients clearly intending to withdraw from the study if not randomised in the willing arm or patients who cannot be regularly followed up for psychological, social, familiar or geographic reasons.