News Releases

Tokyo, January 26, 2011 — Taiho Pharmaceutical Co., Ltd., announced today the results of its Gemcitabine and TS-1 Trial (GEST) on advanced pancreatic cancer. The objective of the trial was to verify that TS-1 alone has the same efficacy for treatment of advanced pancreatic cancer as does gemcitabine alone, regarded as the standard treatment, and also to verify that treatment with a combination of TS-1 and gemcitabine is superior to treatment with gemcitabine alone. The trial results verified that treatment with TS-1 alone does show equivalent efficacy versus the standard treatment of gemcitabine alone. Good results were also obtained regarding safety. TS-1 and gemcitabine combination therapy, on the other hand, was not shown to be superior to treatment with gemcitabine alone in terms of survival at a statistically significant level. It is hoped that this trial will lead to the addition of TS-1, a member of the fluoropyrimidine class of chemotherapeutic agents, as a standard treatment option for advanced pancreatic cancer. Detailed trial results will be presented at a medical convention to be held in 2011. Going forward, Taiho Pharmaceutical will use the trial data to continue to develop better treatments for pancreatic cancer.

A member of the fluoropyrimidine class of chemotherapeutic agents, TS-1 is a combination of three pharmacological compounds: tegafur, an antimetabolite agent that, after absorption, is converted into the anti-cancer agent fluorouracil (5-FU); gimeracil (5-chloro-2, 4-dihydroxypyridine, or CDHP), which decreases the degradation of 5-FU by the body; and oteracil (Oxo), which decreases 5-FU phosphorylation in the gastrointestinal tract. Developed as a gastric cancer treatment, TS-1 has become a standard of care for the treatment of gastric cancer in Japan since its initial approval there in 1999. TS-1 is also approved for patients with gastric cancer in South Korea, China, Singapore, and Taiwan. TS-1 was subsequently approved in Japan for six additional indications: for the treatment of colorectal, head and neck, non-small cell lung, unresectable or recurrent breast, pancreatic, and biliary tract cancers. To date, TS-1 has been used by more than 870,000 patients in Japan and Asia.

The trial was conducted jointly in Japan and Taiwan with the participation of more than 80 medical institutions. It compared subjects—patients with unresectable advanced pancreatic cancer—assigned to one of three groups: a group treated with gemcitabine alone, a group treated with the oral anticancer agent TS-1 alone, and a group treated with a combination of TS-1 and gemcitabine. Outcome measures included overall survival, progression-free survival, and safety. The group treated with gemcitabine alone followed a schedule in which one course lasted 28 days with gemcitabine administered by intravenous drip infusion at 1,000 mg/m² on days 1, 8, and 15 with day 22 being a day of rest. The group treated with TS-1 alone followed a schedule in which one course lasted 42 days with TS-1 administered orally at a dose prescribed according to body surface area (80mg, 100mg, or 120mg/day) twice daily for 28 days followed by a two-week rest period. The group treated with a combination of TS-1 and gemcitabine followed a schedule in which one course lasted 21 days with gemcitabine administered by intravenous drip infusion at 1,000 mg/m² on days 1 and 8 and TS-1 co-administered orally at a dose prescribed according to body surface area (60mg, 80mg, or 100mg/day) twice daily for 14 days followed by a one-week rest period. In each treatment arm administration of the curative agent(s) was repeated until stated criteria for termination were fulfilled.