Adjuvant oxaliplatin with S-1 (SOX) versus S-1 for stage II-III gastric cancer (CAPITAL): A randomized, open-label, phase 3 trial.

BACKGROUND

Adjuvant chemotherapy following D2 gastrectomy constitutes the standard-of-care for resectable gastric or gastroesophageal junction (GEJ) carcinoma. The CAPITAL trial is a multicenter, randomized, phase 3 study, aiming to assess the efficacy and safety of adjuvant oxaliplatin plus S-1 (SOX) versus S-1 alone.

METHODS

Patients with histologically confirmed pathological stage II-III gastric or GEJ adenocarcinoma after gastrectomy with D2 lymphadenectomy were randomly assigned (1:1) to receive either the SOX regimen (n = 362) or the S-1 regimen (n = 362). The primary endpoint was overall survival. This study is registered with ClinicalTrials.gov (NCT01795027).

FINDINGS: The median follow-up was 74.0 months (interquartile range [IQR], 35.5-89.3). The 5-year overall survival rates were 70.9% (95% confidence interval [CI], 66.0-76.1) in the SOX group and 62.9% (95% CI, 57.8-68.5) in the S-1 group (hazard ratio [HR], 0.74; 95% CI, 0.58-0.95; p = 0.018). The 3- and 5-year disease-free survival rates were 71.2% (95% CI, 66.5-76.3) and 66.2% (95% CI, 61.2-71.6) in the SOX group, as compared with 65.1% (95% CI, 60.2-70.5) and 55.6% (95% CI, 50.4-61.3) in the S-1 group (HR, 0.76; 95% CI, 0.61-0.96). Treatment-related adverse events of grade 3-4 occurred in 87 (25%) of 349 patients in the SOX group and 45 (13%) of 347 patients in the S-1 group. The most common grade 3-4 adverse event was neutropenia, occurring in 44 (13%) of 349 patients in the SOX group and 23 (7%) of 347 patients in the S-1 group.

CONCLUSIONS

The addition of adjuvant oxaliplatin to S-1 chemotherapy significantly improved overall survival and disease-free survival in patients with gastric cancer.

FUNDING: This research was supported by the National Natural Science Foundation of China (82573092 and 82573387).