News Releases

Taiho Pharmaceutical Co., Ltd., announced today that the results of a five-year follow-up study in the Adjuvant Chemotherapy Trial of TS-1 for Gastric Cancer (ACTS-GC) was announced at the meeting of the European Society for Medical Oncology held in Milan, Italy, on October 11, 2010.

The trial, in which over 100 medical institutions from around Japan participated, was initiated with the objective of comparing overall survival and other outcome measures of patients who received curative resection for stage II or stage III gastric cancer, and who were randomly assigned to a cohort either receiving surgery only or surgery followed by administration of S-1 (TS-1®) for one year.*1 The independent data and safety monitoring committee acknowledged the efficacy of TS-1 administration based on the results of an interim analysis conducted about three years into the follow-up study period, and recommended the trial be discontinued and the analysis results published. The results have since been reported in the New England Journal of Medicine.*2

The trial was concluded since the efficacy of TS-1 administration had been verified. Nevertheless, Taiho Pharmaceutical thereafter continued the five-year follow-up study as special surveillance with the cooperation of the medical institutions that had participated in the trial, based on the view that the results of a five-year follow-up study would benefit future medical research. The results of the follow-up study are as follows: five-year overall survival was 61.1% in the surgery-only cohort versus 71.7% in the TS-1 cohort, with a hazard ratio of 0.669 and 95% confidence interval of 0.540 – 0.828; five-year relapse-free survival was 53.1% in the surgery-only cohort versus 65.4% in the TS-1 cohort, with a hazard ratio of 0.653 and a 95% confidence interval of 0.537 – 0.793. These results strongly substantiate the results reported at the three-year mark.

These results are good news for patients who will undergo gastric surgery, since they show again that one-year postoperative administration of TS-1 improves overall survival after five years of patients who underwent resection for stage II or III gastric cancer. The results are also expected to be reported at the 48th Annual Meeting of the Japan Society of Clinical Oncology, presided by Tsuneharu Miki, MD, Professor, Department of Urology, Kyoto Prefectural University of Medicine, to be held in Kyoto beginning on October 28, 2010.

*1 80 - 120 mg per square meter of body-surface area per day given for four weeks followed by two weeks of no chemotherapy, and then repeated.

*2 Sakuramoto S et al., N Engl J Med 2007; 357: 1810-20