Phase II study of oxaliplatin plus S-1 as first-line treatment for advanced gastric cancer (G-SOX study)

The efficacy and safety of oxaliplatin combined with S-1 (SOX regimen) for unresectable advanced or recurrent gastric cancer were investigated.

Oxaliplatin was administered i.v. (100 mg/m(2)) on day 1, while S-1 was administered orally (80 mg/m(2)/day, b.i.d.) for 14 days followed by a 7-day rest. This schedule was repeated every 3 weeks.

Among 55 patients enrolled, one patient received oxaliplatin for the other study, and three patients were considered unsuitable against the inclusion criteria. Accordingly, 51 patients were assessable for efficacy. The response rate was 59%, and the disease control rate was 84%. The median progression-free survival time was 6.5 months, the 1-year survival rate was 71%, and the median survival time was 16.5 months. In 54 patients assessed for safety, the major grade 3/4 toxic effects were neutropenia (22%), thrombocytopenia (13%), anemia (9%), anorexia (6%), fatigue (6%), and sensory neuropathy (4%).

These findings indicate that SOX regimen with oxaliplatin at a dose of 100 mg/m(2) is feasible and shows promising efficacy against advanced gastric cancer.