Multicenter phase II trial of S-1 plus cisplatin in patients with untreated advanced gastric or gastroesophageal junction adenocarcinoma

Purpose S-1 plus cisplatin is considered highly active in Japanese gastric cancer patients. We conducted a phase II multi-institutional trial, in the West, in patients with untreated advanced gastric or gastroesophageal junction adenocarcinoma to evaluate activity and safety of this combination. Methods Patients received cisplatin intravenously at 75 mg/m(2) on day 1 and S-1 orally at 25 mg/m(2)/dose bid (50 mg/m(2)/d) on days 1 to 21, repeated every 28 days. Patients with histologic proof of gastric or gastroesophageal junction adenocarcinoma with a Karnofsky performance status (KPS) of >= 70% and near-normal organ function were eligible. All patients provided a written informed consent. To observe a 45% confirmed overall response rate (ORR), 41 assessable patients were needed. Results All 47 patients were assessed for safety and survival, and 41 patients were assessed for ORR. The median age was 56 years and median KPS was 80%. The median number of chemotherapy cycles was four. The confirmed ORR was 51% (95% Cl, 35% to 67%) and it was 49% by an independent review. At the 6-month interval, 71% of patients were alive, with a median survival time of 10.9 months. Frequent grade 3 or 4 toxicities included fatigue (26%), neutropenia (26%), vomiting (17%), diarrhea (15%), and nausea (15%); however, stomatitis (2%) and febrile neutropenia (2%) were uncommon. There was one (2%) treatment-related death. Conclusion S-1 plus cisplatin is active against gastric cancer and has a favorable toxicity profile. A global phase III study of S-1 plus cisplatin versus fluorouracil plus cisplatin currently is accruing patients.