Avastin and Chemotherapy Followed by a KRAS Stratified Randomization to Maintenance Treatment for First Line Treatment of Metastatic Colorectal Cancer.

Patients with metastatic colorectal cancer will be treated with chemotherapy according to investigators choice. In addition to chemotherapy treatment, treatment with bevacizumab will be given concomitantly. This treatment will continue during 18 weeks. Meanwhile, the patients KRAS status will be tested. After having fulfilled these 18 weeks of induction treatment, patients who has responded (complete response/partial response versus stable disease) will be randomized to maintenance treatment. Patients with KRAS WT will be randomized to either bevacizumab alone, or to bevacizumab and erlotinib. Patient with KRAS mutation will be randomized to either bevacizumab, or metronomic capecitabine. Translational research is performed, with purpose to find predictive factors in blood and tumor tissue.

Inclusion Criteria:

• Untreated metastatic colorectal carcinoma
• Age 18 yrs or over
• Measurable disease according to Response Evaluation Criteria in solid Tumors (RECIST criteria)
• ECOG performance status 0 or 1
• Life expectancy more than 3 months
• Adequate haematological, renal and liver function
• Tumor tissue available for determination of KRAS mutational status
• Blood sample and paraffin embedded tumor tissue for translational research

Exclusion Criteria:

• Adjuvant therapy within 6 months
• CNS metastases
• Clinically significant atherosclerotic vascular disease