A Phase I/II Trial of TS-1 and Oxaliplatin in Patients With Advanced Colorectal Cancer

Capecitabine and oxaliplatin(XELOX) is active first-line therapy for patients with metastatic colorectal cancer. Phase II study of TS-1, a novel oral fluoropyrimidine derivative, showed activity in patients with metastatic colorectal carcinoma. Preclinical data of TS-1 with oxaliplatin showed synergistic activity in vivo human colorectal cancer xenograft. There is no data about the optimal dose of TS-1 with 2 weeks schedule combined with oxaliplatin. Therefore in a phase I study, we would like to determine the maximum tolerated dose(MTD) of TS-1 and oxaliplatin and define the recommended dose for subsequent phase II study. And then, in a phase II study we would like to evaluate the efficacy(response rates) and toxicities of the new combination regimen in advanced colorectal cancer.