Study of ctDNA Guided Change in Tx for Refractory Minimal Residual Disease in Colon Adenocarcinomas

Given PO

Given IV

6 cycles for a 2-week regimen (infusional 5FU based) and up to 4 cycles for a 3-week regimen (oral capecitabine based) after randomization

To be performed within 6-8 weeks of Cycle 1 Day 1. A Mid-treatment ctDNA is to be completed within 6 - 8 weeks of starting treatment. ctDNA is to also be completed within four weeks after completion of study treatment (+/- two weeks)