[Clinical study of TS-1 therapy for inoperable and recurrent gastric cancer]

The clinical efficacy and safety of TS-1 therapy were studied retrospectively in patients with inoperable and recurrent gastric cancer. The subjects were 45 patients who were treated with TS-1 for more than 4 weeks at our center between May 1999 and July 2002. The objective overall response rate was 32% (14/44; 95% confidence interval, CI, 19-48). The response rate in the chemo-naive patients was 44% (11/25; 95% CI, 24-65), and that in the patients with previous chemotherapy was 16% (3/19; 95% CI, 3.4-40). Although doses or durations of TS-1 administration were reduced in 22 patients (reduction group) due to adverse effects or poor performance status, they achieved a fairly high response rate of 38% (8/21). For primary lesions, the response rate was 30% (8/27). The prevalence of adverse reactions with a grade of 3 or 4 was 36%. However, the prevalence of each grade 3 or 4 adverse effect was relatively low, at 13% for neutropenia, and around 5% for anorexia, nausea, vomiting, and diarrhea. The median administration period was 10 weeks (4-47 weeks) in all patients and 11 weeks (6-47 weeks) in the reduction group. The relative dose intensity was 0.89 in all patients and 0.81 in the reduction group. In patients who were treated until August 2001, the median survival time (MST) was 13 months with 1-year and 2-year survival rates of 53% and 14%, respectively. These results were similar to those reported in the phase II study for the new drug approval. This study demonstrated the reproducible activity and safety of TS-1 in practice.