A Study of FOLFIRI Plus OMP-21M18 as 1st or 2nd-line Treatment in Subjects With Metastatic Colorectal Cancer

The first 6 participants will receive OMP21M18 2.5 mg/kg once every other week, the next 6 participants will receive 5 mg/kg once every other week, and the final 6 participants will receive 10 mg/kg once every other week. A Data Safety Monitoring Board (DSMB) will review the data for the 6 participants in each dose level after the last participant in that group has been treated for 56 days and decide whether it is safe to move up to the next highest dose level. After confirming the optimum dose, 14 additional participants will be treated at the highest dose level that the DSMB considers safe.