Background: It is likely that there are some discrepancies in the safety and efficacy results for anticancer agents between those shown in registration studies for approval and those shown in clinical practice after market release. The aim of this survey was to confirm the safety and efficacy of S-1 for advanced gastric cancer after market release.
Methods: After the approval of S-1 in 1999, all patients had to be registered with the manufacturer for a post-marketing survey, according to the government recommendation. All patients were monitored for safety and survival. The data for all registered patients were updated 1 year after each registration.
Results: During this survey, a total of 4177 patients with advanced gastric cancer were registered. The incidences of all adverse events and of grade 3 or worse adverse events in the 3808 patients evaluable for safety were 74.3% and 25.0%, respectively. In patients with lower creatinine clearance at baseline, the incidences of adverse reactions were higher for all grades combined, as well as for grades 3 or worse. There were 90 (2.4%) early deaths (within 30 days of the initiation of the treatment) and 5 (0.1%) deaths possibly related to the treatment. The median survival time and the 1-year survival rate for all patients evaluable for efficacy (n = 3801) were 8.3 months (95% confidence interval [CI], 8.0-8.6 months) and 33.3% (95% CI, 31.8-34.9%), respectively.
Conclusion: This nationwide survey confirmed that the safety and efficacy profiles of S-1 were similar to those seen in the registration study. These results have proven the utility of this post-marketing survey in assessing the reproducibility of the safety and efficacy results obtained from prior clinical studies.