A multi-institution phase II study of docetaxel and S-1 in combination with trastuzumab for HER2-positive advanced gastric cancer (DASH study)

Background Trastuzumab when combined with fluoropyrimidine and cisplatin was proven to improve survival in patients with human epidermal growth factor receptor 2 (HER2)-positive gastric cancer (GC) in the ToGA study. The safety and efficacy of trastuzumab in combination with docetaxel and S-1 have not yet been evaluated.