The primary objective of this study is to evaluate the efficacy of Irinotecan in combination with FOLFOX+Bevacizumab versus FOLFOX+Bevacizumab alone in the first-line treatment of patients with metastatic colorectal cancer.

5-Fluorouracil and oxaliplatin (FOLFOX-Regimen) in combination with bevacizumab is regarded as standard first-line treatment in metastatic colorectal cancer [Saltz et al., 2008]. Current studies established the role of the FOLFOXIRI regimen [Souglakos et al., 2006, Falcone et al., 2007]. A further intensification of the therapy seems feasible yielding response rates up to 84% and a disease control rate up to 100% [Falcone, 2008, Santomaggio, 2009, Masi, 2010]. This trial evaluates the activity of an intensified first-line therapy for metastatic colorectal cancer compared to standard treatment.

Inclusion Criteria:

1. Patients with histologically confirmed diagnosis of stage IV (UICC) colorectal cancer (primary tumor may be present)

2. Patients with at least one measurable lesion, with size > 1 cm (RECIST v1.1)

3. ECOG Performance status ≤ 2 (ECOG 2, only if tumor related)

4. Patients, who are able to tolerate intensive first lien treatment as judged by the investigator

5. Life expectancy > 3 months

6. Age ≥ 18 years

7. Haematologic function: ANC ≥ 1.5 x 109/L, platelets ≥ 100 x109/L, hemoglobin

   • 9 g/dl or 5.59 mmol/l

8. Patients not receiving therapeutic anticoagulation must have an INR < 1.5 ULN and aPTT < 1.5 ULN within 7 days prior to registration. The use of full dose anticoagulants is allowed as long as the INR or aPTT is within therapeutic limits (according to the medical standard in the institution) and the patient has been on a stable dose for anticoagulants for at least two weeks at the time of registration.

9. Adequate liver function as measured by serum transaminases (AST & ALT) ≤ 2.5 x ULN (in case of liver metastases < 5 x ULN) and total bilirubin ≤ 1.5 x ULN

10. Adequate renal function: Serum creatinine ≤ 1.5 x ULN

11. Signed, written informed consent

Exclusion Criteria:

1. Patients with histologically confirmed diagnosis of stage IV (UICC) colorectal cancer (primary tumor may be present)

2. Patients with at least one measurable lesion, with size > 1 cm (RECIST v1.1)

3. ECOG Performance status ≤ 2 (ECOG 2, only if tumor related)

4. Patients, who are able to tolerate intensive first lien treatment as judged by the investigator

5. Life expectancy > 3 months

6. Age ≥ 18 years

7. Haematologic function: ANC ≥ 1.5 x 109/L, platelets ≥ 100 x109/L, hemoglobin

   • 9 g/dl or 5.59 mmol/l

8. Patients not receiving therapeutic anticoagulation must have an INR < 1.5 ULN and aPTT < 1.5 ULN within 7 days prior to registration. The use of full dose anticoagulants is allowed as long as the INR or aPTT is within therapeutic limits (according to the medical standard in the institution) and the patient has been on a stable dose for anticoagulants for at least two weeks at the time of registration.

9. Adequate liver function as measured by serum transaminases (AST & ALT) ≤ 2.5 x ULN (in case of liver metastases < 5 x ULN) and total bilirubin ≤ 1.5 x ULN

10. Adequate renal function: Serum creatinine ≤ 1.5 x ULN

11. Signed, written informed consent