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Taiho Pharmaceutical Co., Ltd. (HQ: Tokyo, President: Masayuki Kobayashi) announced today the results of its interim analysis of randomized phase III trial (JASPAC¹ 01) adjuvant chemotherapy with gemcitabine vs. TS-1 in patients with resected pancreatic cancer, which was performed on 385 patients with resected pancreatic cancer.

1 Japan Adjuvant Study Group of Pancreatic Cancer

The trial was conducted as a Pharma Valley Project by Shizuoka Industrial Foundation, which was under contract with Taiho Pharmaceutical. It was a Phase III clinical trial comparing the standard treatment gemcitabine (GEM) monotherapy with TS-1 monotherapy in patients with resected pancreatic cancer.

Taiho Pharmaceutical has been advised by the JASPAC Trial Group that it has received a recommendation from the Data and Safety Monitoring Committee to publish its findings immediately due to the effectiveness of the drug.

This recommendation was issued in order to publish the results early to allow the drug to be used in clinical settings. This decision was made due to the fact that TS-1 was judged in the interim analysis, for which overall survival time was the primary endpoint, to have satisfied the conditions stated below:

As a result of an investigation using previously defined statistical conditions, the TS-1 group has been verified to be non-inferior, i.e., the hazard ratio of the TS-1 group relative to the GEM group is 0.79 or below.

The safety profile of TS-1 in the adjuvant setting for resected pancreatic cancer is very similar to that in the palliative for unresected or recurrent disease, and it is within allowable limits.

The JASPAC Trial Group will release the results of this trial without delay to the institutions that participated in the trial and will present the results at international conferences in 2013 and at conferences held in Japan thereafter.

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 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. TS-1 is also approved for patients with gastric cancer in South Korea, China, Singapore, Taiwan, Thailand, Hong Kong, and Malaysia in Asia, Sweden, Denmark, Norway, Finland, U.K., Austria, Bulgaria, Germany in Europe.

Thirty-three institutions participated in this study. It was begun in April 2007 and was conducted over three years, compiling data from 385 patients with resected pancreatic cancer (UICC stage II and below or stage III patients with additional resection of the celiac artery). The trial compared a group treated only with gemcitabine and a group treated only with the oral anti-tumor agent TS-1. The primary endpoint was overall survival time, and the secondary endpoints were survival without recurrence and safety. The gemcitabine monotherapy group was administered by intravenous drip infusion at 1,000 mg/m2 on days 1, 8, and 15 with day 22 being a day of rest, 28-day courses completed over a total of six months. The group treated with TS-1 alone followed a schedule in which TS-1 administered orally at a dose prescribed in accordance with body surface area (80, 100 or 120 mg/day), twice daily for 28 days, followed by a two-week rest period, repeated every six weeks to a totally four courses (six months).