A randomized phase III study of sox (S-1/oxaliplatin) versus COX (capecitabine/oxaliplatin) in patients with advanced colorectal cancer.

Abstract

3524 Background: A regimen consisting of capecitabine and oxaliplatin (COX) is widely used in Korea in the first-line treatment of metastatic colorectal cancer (MCRC). S-1 may have considerable activity compared with capecitabine. Phase I and II studies showed that S-1 plus oxaliplatin (SOX) might have at least comparable activity with COX in MCRC. The aim of study was to evaluate whether SOX is noninferior to COX in terms of progression free survival (PFS) in patients previously untreated with systemic therapy for MCRC. Our hypothesis was that SOX is non-inferior to COX if the upper limit of 95% confidence interval for hazard ratio (HZ) between those two arms is below 1.4327, which comes from the non-inferiority margin of 13% in progress-free survival at 15 months. Methods: This study was a randomized, two-arm, non-inferiority, phase III comparison of SOX versus COX. Patients with MCRC were stratified according to primary site (colon vs. rectum), previous treatment (adjuvant therapy vs. none) and status ...