Phase I study of 3-weekly combination chemotherapy using epirubicin, oxaliplatin, and S-1 (EOS) in patients with previously untreated advanced gastric cancer.

Purpose: This study was performed to determine the recommended dose (RD) and dose-limiting toxicity (DLT) associated with epirubicin, oxaliplatin, and S-1 (EOS) combination therapy in patients with previously untreated advanced gastric cancer (AGC).

Materials And Methods: Previously untreated patients with histologically proven metastatic AGC, with an ECOG performance status of 0-2, were enrolled in this study. A fixed dose of epirubicin (50 mg/m(2)) and oxaliplatin (130 mg/m(2)) was intravenously administered on day 1 of treatment, followed by oral S-1 administration twice daily on days 1-14. The S-1 dose was escalated according to the following schedule: level I, 35 mg/m(2); level II, 40 mg/m(2); level III, 45 mg/m(2); Level IV, 50 mg/m(2). Each cycle was repeated every 21 days. DLTs were evaluated during the first two cycles of treatment.

Results: Nineteen patients with a median age of 53 years (range, 40-71 years) were enrolled in this study. One case of DLT (grade 4 neutropenia lasting more than 5 days) developed from among the six dose level II patients, while 2 DLTs (grade 3 diarrhea and nausea) were observed among the 4 dose level III patients. Based on these results, dose level II was determined as the RD. Of the 13 patients with measurable lesions, eight achieved partial response, three showed stable disease, and the objective response rate was 61.5 % (95 % confidence interval (CI), 13.3-66.6 %). The median progression-free survival and overall survival of all patients was 6.8 months (95 % CI, 1.4-9.5 months) and 13.3 months (95 % CI, 1.9-24.6 months), respectively.

Conclusion: The RD of the EOS regimen in patients with previously untreated AGC was 50 mg/m(2) of epirubicin and 130 mg/m(2) of oxaliplatin on day 1, with administration of 40 mg/m(2) of S-1 twice a day on days 1-14 for each 21-day cycle. The EOS regimen described produced promising results.