To assess the efficacy of FOLFOX4 in combination with cetuximab, weekly and FOLFOX4 in combination with cetuximab, biweekly.

This multicenter randomized phase II study will enroll approximately 150 patients with metastatic Colorectal Cancer. Patients are randomized in Arm A(FOLFOX4 in combination with weekly Cetuximab) or Arm B (FOLFOX4 in combination with biweekly Cetuximab). Both efficacy and safety data will be collected. The investigator will assess response to treatment every 8 weeks based on the imaging.

Following permanent treatment cessation, patients will be followed-up for survival.

Inclusion Criteria:

• Signed written informed consent
• Male or female ≥ 18 years of age
• Diagnosis of histologically confirmed adenocarcinoma of the colon or rectum
• Metastatic colorectal carcinoma not suitable for curative-intent resection- Availability of tumor sample (or able and willing to provide tumor sample) for EGFR assessment
• Presence of at least one lesion measurable unidimensionally by CT scan or MRI. (Target lesion(s) must not lie within an irradiated area)
• Karnofsky performance status of > 80 at study entry
• Leucocytes ≥ 3.0 x 10 9/L and neutrophils ≥1.5 x 10 9/L, platelets ≥ 100 x 10 9/L, and hemoglobin ≥ 9 g/dL.
• Bilirubin ≥ 1.5 x ULN
• ASAT and ALAT ≤ 2.5 x ULN (≤5 x ULN if liver metastasis are present)
• Serum creatinine ≤ 1.5 x ULN

Exclusion Criteria:

• Brain metastasis (known or suspected)
• Previous chemotherapy for metastatic disease. Prior adjuvant chemotherapy is allowed if the chemotherapy treatment free interval is > 6 months.
• Surgery (excluding diagnostic biopsy) or irradiation within 4 weeks prior to study entry
• Concurrent chronic systemic immune therapy, chemotherapy, or hormone therapy not indicated in the study protocol
• Any investigational agent(s) within 4 weeks prior to entry
• Previous exposure to EGFR-pathway targeting therapy
• Clinically relevant coronary artery disease or a history of a myocardial infarction within the last 12 months
• Acute or subacute intestinal occlusion or history of inflammatory bowel disease
• Pre-existing neuropathy > grade 1. In case of prior oxaliplatin containing adjuvant chemotherapy: pre-existing neuropathy ≥ 1.
• Known grade 3 or 4 allergic reaction to any of the components of the treatment.
• Any concurrent malignancy other than non-melanoma skin cancer, or carcinoma in situ of the cervix. (Patients with a previous malignancy but without evidence of disease for ≥ 5 years will be allowed to enter the trial)
• Pregnancy or lactation
• Inadequate contraception (male or female patients) if of childbearing or procreational potential
• Known drug abuse/ alcohol abuse
• Legal incapacity or limited legal capacity
• Medical or psychological condition which in the opinion of the investigator would not permit the patient to complete the study or sign meaningful informed consent