A Phase Iii Study Of S-1 Plus Cisplatin Versus Fluorouracil Plus Cisplatin In Patients With Advanced Gastric Or Gastroesophageal Junction Adenocarcinoma

4025 Background: A combination of S-1 and cisplatin (DDP) has been shown to be effective and safe for the first-line treatment of advanced gastric cancer in Japan. This is the first randomized phase III trial to compare S-1 plus DDP with 5-fluorouracil (5-Fu) plus DDP in Asia. Methods: This is an open-label, multicenter, phase 3, randomized controlled study. Patients with gastric or gastro-oesophageal junction adenocarcinoma were eligible for inclusion. Patients were randomly assigned in a 1:1 ratio to receive S-1 plus DDP (experiment group) or 5-Fu plus DDP (control group) for 6 cycles. In the experiment group, the dose of S-1 was 80 mg/m2/day, po, twice daily on day 1-21 and DDP was 20mg/m2 iv on day 1-4, repeat every 5 weeks. In the control group, 5-Fu was given as 0.8g/m2/d CI 120h ,and the dose of DDP was the same with the experiment group, while repeat every 4 weeks. Allocation was by block randomization stratified by Eastern Cooperative Oncology Group performance status, sites of metastasis and prior gastrectomy. The primary endpoint was time to progression (TTP). Secondary end points included time to failure (TTF), overall survival (OS), and quality of life. Results: Totally 255 patients were enrolled into the study, of whom 236 were included in the analysis (n=120; n=116). Median TTP was 5.51 months (95% CI 4.59-6.26) in those assigned to experiment group compared with 4.62 months (95% CI 4.00-6.33) in the control group (hazard ratio [HR] 1.03; 95%CI 0.76-1.39, p=0.86). In the experiment and control groups, response rates were 22.5% vs 21.5%; P=0.86. Median OS was 10.00 months (95% CI 8.59-14.52) in the experiment group compared with 10.46 months (8.92-13.84) in the control group (HR 1.05; 95%CI 0.71-1.54, p=0.82). The most common adverse events in both groups were anemia (S-1 plus cisplatin, 80.17% vs 5-Fu plus cisplatin, 71.19%), leukopenia (71.90% vs 62.71%), neutropenia (68.60% vs 55.93%), nausea (50.41% vs 60.17%), thrombocytopenia (44.63% vs 26.27%), vomiting (42.98% vs 42.37%) and anorexia (38.02% vs 41.53%). Conclusions: S-1 plus DDP is an effective and tolerable option for patients with advanced gastric or gastro-oesophageal junction adenocarcinoma. Clinical trial information: NCT01198392.