National multicentric phase II trial evaluating whether single agent cetuximab is effective as maintenance therapy after 8 cycles of first line FOLFIRI plus cetuximab in mCRC patients with KRAS and NRAS wild-type genes, assessed by progression-free survival at 6 months after start of maintenance therapy.

Inclusion Criteria:

1. Histologically confirmed colorectal cancer
2. KRAS and NRAS wild-type genes after analysis of mutation status from the primary tumour or metastasis
3. Non resectable metastatic disease in a curative intent
4. No prior chemotherapy except for fluoropyrimidines with or without oxaliplatin-based adjuvant treatment, at least 6 months before inclusion
5. At least one measurable tumour target (higher than 20 mm) according to RECIST criteria, which has never been irradiated
6. Life expectancy above 3 months
7. Performance Status ≤2 (WHO)
8. Patient ≥18 years-old
9. Acceptable blood test
10. Patient having signed a written informed consent form

Exclusion Criteria:

1. Known and/or symptomatic brain metastases
2. Known allergy to one of treatment components
3. Neurological or psychiatric condition which could interfere with good treatment compliance
4. Current anti-tumour treatment : chemotherapy or targeted therapy or radiotherapy ≤ 14 days before randomisation
5. Other severe conditions such as: respiratory failure. History of interstitial lung disease e.g. pneumonitis or pulmonary fibrosis or evidence of interstitial lung disease on baseline chest CT scan
6. Clinically significant cardiovascular disease (including myocardial infarction, unstable angina, symptomatic congestive heart failure, serious uncontrolled cardiac arrhythmia) 6 months before enrollment/randomization
7. Concomitant severe infection
8. History of cancer (except skin cancer other than melanoma or an in situ cervical epithelioma or other solid tumour treated for curative purposes without signs of the condition and with no treatment administered in the 5 years before randomisation.)
9. Patient already included in another clinical trial with an investigational molecule
10. Prior treatment with anti-EGFr antibodies (e.g. panitumumab (Vectibix® or cetuximab / Erbitux® ) or treatment with small EGFr inhibitor molecules (e.g., erlotinib / Tarceva®)
11. Pregnant female, likely to be or currently breastfeeding, or planning to become pregnant within 6 months after the end of treatment or absence of effective contraception for males and females of childbearing age during treatment and for 6 months (male or female) after the end of treatment
12. Those deprived of their freedom or under guardianship
13. Impossibility of undergoing trial's medical follow-up for geographical, social or psychological reasons