<qa>  What is the randomized, multicenter, open label study?This randomized, multicenter, open label study will evaluate the safety and efficacy of RO5083945 in combination with FOLFIRI as compared to FOLFIRI plus cetuximab or FOLFIRI alone as second line treatment in patients with metastatic colorectal cancer. Patients will be randomized to receive RO5083945 1400 mg intravenously on Day 1 and Day 8 and every 2 weeks thereafter plus FOLFIRI standard iv chemotherapy or FOLFIRI plus cetuximab 400 mgm2 iv on Day 1 followed by 250 mgm2 iv every week or FOLFIRI alone. Anticipated time on study treatment is until disease progression or unacceptable toxicity occurs. 