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June 03, 2014
Taiho Pharmaceutical Co., Ltd.

Results of Phase III Clinical Study (SELECT BC) of TS-1 Treatment for Metastatic Breast Cancer Announced at ASCO®

Taiho Pharmaceutical Co., Ltd. (HQ: Tokyo, President and Representative Director: Masayuki Kobayashi) announced today that the results of the SELECT BC*1 study conducted in Japan (randomized controlled study of taxane and TS-1 on metastatic breast cancer) had been presented at the 50th Annual Meeting of the American Society of Clinical Oncology® (ASCO® ) held in Chicago from May 30 to June 3 (abstract no. 1012).

For advanced, recurrent breast cancer with distant metastasis, SELECT BC is the Phase III clinical study that demonstrated the ability of TS-1 monotherapy for the first time to prolong life when used as a first line chemotherapy.

Study Results

The primary endpoint of overall survival (OS) was 35.0 months in the TS-1 arm and 37.2 months in the taxane arm, demonstrating the non-inferiority of TS-1 in OS (hazard ratio = 1.05, 95% confidence interval: 0.86 – 1.27, non-inferiority test p=0.015).

In the TS-1 arm, the main adverse events of grade 3*2 or higher were neutropenia (6.8%), fatigue (3.3%), diarrhea (2.6%), and anorexia (2.6%). Alopecia was 4.9% for all grades*2.

The results of the study represent a major contribution to medical professionals engaged in cancer treatment as well as patients undergoing cancer treatment.

Taiho remains dedicated to continuing its efforts to develop new cancer treatments.

About SELECT BC study

The SELECT BC study was conducted by the Comprehensive Support Project for Oncology Research of Public Health Research Foundation (PHRF-CSPOR) as a physician-initiated study under contract with and funded by Taiho. It is a Phase III study comparing TS-1 with taxane, a standard treatment, as a first line chemotherapy on advanced, recurrent breast cancer with distant metastasis. The study was designed based on the following concept. As the goals of the treatment of metastatic breast cancer are prolonged survival time and improvement of patients' quality of life (QOL), if OS is not inferior, then the selection of a drug as a first line chemotherapy would be based on adverse drug reactions and QOL, not on response rate. The study was conducted between October 2006 and July 2010 at 258 medical facilities in Japan. A total of 618 patients were registered for the study.

About TS-1

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 in the liver; and oteracil (Oxo), which decreases 5-FU phosphorylation in the gastrointestinal tract. Developed as a gastric cancer treatment, TS-1 was first approved in Japan in 1999 and has become a standard of care for the treatment of gastric cancer. TS-1 was subsequently approved in Japan for six additional indications: for the treatment of colorectal, head and neck, non-small cell lung, and inoperable or recurrent breast, pancreatic, and biliary tract cancers. TS-1 is also approved for patients with gastric cancer in 7 regions and countries*3 in Asia, and in 19 European countries.*3

*1: SELection of Effective ChemoTherapy for Breast Cancer

*2: Common Terminology Criteria for Adverse Events (CTCAE) v3.0

*3: As of May 2014

Information in this news release was current as of the original release date.

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