Safety and Effectiveness Study of Chemotherapy and Ziv-aflibercept to Treat Metastatic Colorectal Cancer

All patients will receive an induction regimen with mFOLFOX6 (5-FU 400 mg/m2 IV bolus Day 1 + leucovorin 400 mg/m2 IV Day 1 + oxaliplatin 85 mg/m2 IV Day 1 followed by 5-FU 2400 mg/m2 by continuous intravenous infusion (CIV infusion) over 46 hours \[Day 1 and 2\]) + ziv-aflibercept (4 mg/kg on Day 1) every 14 days for 6 cycles. Patients attaining stable disease or better after 6 cycles of induction therapy will be randomized to receive a continuation regimen of either 5-FU/LV + ziv-aflibercept IV \[4 mg/kg Day 1\]) every 14 days, as the investigational arm; or 5-FU/LV alone every 14 days, as the control arm, until disease progression. Toxicity will be graded according to the National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events version 4.0. Submission of archived primary tumor tissue and blood samples for FC-8 correlative science studies will be a study requirement for all patients. Submissions will include primary tumor specimens from the diagnostic biopsy sample or another previous surgery and blood samples collected before the start of study therapy, prior to starting each even numbered cycle of therapy, (i.e., Cycles 2, 4, and 6) and at the time of disease progression or end of study therapy. The total study accrual will be up to 120 patients over a period of 24 months in order to provide 90 patients for randomization to the continuation regimen. Patients will be randomized 2:1 to receive the continuation regimen of 5-FU/LV + ziv-aflibercept (Arm 2, 60 patients) or 5-FU/LV alone (Arm 1, 30 patients). In both arms, clinical response will be assessed by radiological examination every eight weeks during the continuation regimen course.