 CT-2106, a camptothecin CPT conjugate, is a new generation of topoisomerase I inhibitors designed to deliver higher, more effective chemotherapy to tumor tissue with less toxicity to normal tissues. The objective of this study is to determine the dose limiting toxicities, safety profile and antitumor activity of CT-2016 in combination with 5-FU and folic acid for the treatment of colorectal cancer. 