Neoadjuvant Docetaxel, Oxaliplatin, and S-1 Plus Surgery and Adjuvant S-1 for Resectable Advanced Gastric Cancer: Updated Overall Survival Outcomes from Phase III PRODIGY

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported. The phase III PRODIGY study demonstrated that neoadjuvant chemotherapy with docetaxel, oxaliplatin, and S-1 (DOS) followed by surgery and adjuvant S-1 chemotherapy (CSC) improved progression-free survival (PFS) compared with surgery followed by adjuvant S-1 (SC) for patients with resectable locally advanced gastric cancer (LAGC) with clinical T2-3N+ or T4Nany disease. The primary end point was PFS. Overall survival (OS) was the secondary end point. We herein report the long-term follow-up outcomes, including OS, from this trial. A total of 238 and 246 patients were randomly assigned to the CSC and SC arms, respectively, and were treated (full analysis set). As of the data cutoff (September 2022), the median follow-up duration of the surviving patients was 99.5 months. Compared with SC, CSC significantly increased the OS (adjusted hazard ratio [HR], 0.72; stratified log-rank P = .027) with an 8-year OS rate of 63.0% and 55.1% for the CSC and SC arms, respectively. CSC also significantly improved the PFS (HR, 0.70; stratified log-rank P = .016). In conclusion, neoadjuvant DOS chemotherapy, as part of perioperative chemotherapy, prolonged the OS of Asian patients with LAGC relative to patients treated with surgery and adjuvant S-1. It should be considered one of the standard treatment options for patients with LAGC in Asia.