 This is a Phase 2, multicenter, multiple-arm, open-label study to evaluate the efficacy, safety, and tolerability of EZN-2208. EZN-2208 will be administered as a single agent in patients with K-RAS mutations in the tumors. Patients with wild type K-RAS in tumors will be randomized to EZN-2208 cetuximab or to standard of care Camptosar cetuximab, patients must have failed regimens containing irinotecan Camptosar, CPT-11, oxaliplatin Eloxatin, and fluoropyrimidine. 