Safety and Efficacy Study of mFOLFOX-6 Plus Cetuximab for 8 Cycles Followed by mFOLFOX-6 Plus Cetuximab or Single Agent Cetuximab as Maintenance Therapy in Patients With Metastatic Colorectal Cancer and WT KRAS Tumours

Inclusion Criteria:

• Written informed consent.

• Patients of an age ≥ 18 years and < 71

• Patients with an ECOG performance status ≤ 2

• Confirmed histological diagnosis of colorectal carcinoma with metastatic disease andwild-type KRAS.

• Presence of at least one target lesion that is measurable one-dimensionally (notlocated in an irradiated region).

• Life expectancy greater than 12 weeks.

• First evidence of chemotherapy-naïve metastatic disease. Adjuvant chemotherapy isallowed if it has been more than 6 months since the treatment was finished and therehave been no signs of disease progression, neither during treatment nor during the 6months following its completion.

• Adequate medullar reserve:

• Absolute neutrophil count ≥ 1.5 x 109/L

• Platelet count ≥ 100 x 109/L

• Haemoglobin ≥ 9 g/dL

• Adequate renal function: Creatinine clearance > 30 mL/min, calculated using theCockroff-Gault formula, or a serum creatinine < 2 mg/dL or 177 umol/L

• An adequate liver function: ASAT (SGOT) and ALAT (SGPT) ≤ 2.5 x ULN (≤ 5 x ULN ifthere are liver metastases). Total bilirubin < 1.5 x ULN. Alkaline phosphatase ≤ 2.5 xULN ( ≤ 5 x ULN in the case of liver metastases or ≤ 10 x ULN in the case of bonemetastases)

Exclusion Criteria:

• To have received prior systemic treatment for the metastatic disease

• Diagnosis or suspicion of brain or leptomeningeal metastases

• Major surgery or radiotherapy (except for antalgic surgery that does not includemeasurable target lesions) during the 4 weeks prior to inclusion in the study.

• Previous administration of monoclonal antibodies, agents inhibiting EGFR signaltransduction or EGFR-targeted treatment.

• Participation in another clinical trial with drugs within the previous 30 days.

• Neoplasm in the 2 years prior to entering the study, except for non-melanoma skincarcinoma or in situ cervix carcinoma.

• Evidence of previous acute hypersensitivity reaction of any degree to any of thetreatment's components.

• Clinically relevant peripheral neuropathy.

• Signs and symptoms, at the moment of entering the study, of acute or subacute bowelobstruction.

• A history of an acute episode of ischemic heart disease (angina or acute myocardialinfarction) within the previous 12 months or an elevated risk of heart failuredecompensation or uncontrolled arrhythmia.

• Serious active infection, including active tuberculosis and HIV diagnosis.

• Chronic immunological or hormonal treatment, except for hormone replacement treatmentat physiological doses.

• Known drug or alcohol abuse.

• Legal incapacity or limited legal capacity.

• Pregnancy or breastfeeding. Premenopausal women must have a negative pregnancy test inurine or blood before entering the trial. Patients and their partners must takecontraceptive measures (hormonal, barrier, or abstinence) if the possibility ofconception exists, during the study and for 3 months after the end of the treatmentthereof.

• Any geographical or social circumstance or any medical or psychological alterationthat, in the investigator's opinion, will not allow the patient to conclude the study.