News Releases

Taiho Pharmaceutical Co., Ltd. (HQ: Tokyo, President and Representative Director: Masayuki Kobayashi) announced today that results from a Phase II clinical trial of ET-743 (trabectedin), a novel antitumor agent that Taiho has been developing in Japan as a treatment of malignant soft tissue sarcoma (STS), were presented at the 2014 Annual Meeting of the American Society of Clinical Oncology^® (ASCO^®) in Chicago that was held from May 30 to June 3 (Abstract No. 10524). STS is an area of unmet medical needs and a new treatment option has been awaited.

This trial was a Phase II clinical trial conducted in malignant soft tissue sarcoma patients of histological types^*1 reported to have chromosomal translocations, comparing ET-743 arm with best supportive care (BSC) arm as the control. The primary endpoint of the trial was progression-free survival (PFS). 12 medical sites in Japan participated, and 76 patients were enrolled between July 11, 2012 and January 20, 2014.

Analysis of the trial showed that ET-743 arm significantly improved PFS in comparison with the BSC arm. Median PFS (90% confidence interval (CI)) for ET-743 arm and BSC arm were 5.6 m (4.2-7.5) and 0.9 m (0.9-1.0), respectively (p<0.0001; HR=0.07, 90% CI: 0.03-0.14). Median OS (95% CI) was not reached (NR) (12.8-NR) for ET-743 arm and was 8.0 m (7.0-NR) for the BSC arm (p=0.025; HR=0.38, 95% CI: 0.16-0.91).

Commonly reported Grade 3 or 4 adverse drug reactions in the ET-743 arm were neutrophils decreased (66.7%), ALT increased (61.1%), WBC decreased (55.6%), AST increased (41.7%), γ-GTP increased (25.0%), lymphocyte decreased (22.2%), anaemia (19.4%), platelets count decreased (16.7%), and febrile neutropenia (13.9%).

These results showed that ET-743 significantly improves PFS, a clinically meaningful endpoint, in malignant STS patients of histological types reported to have chromosomal translocations, and reported adverse drug reactions were similar to those previously reported in the clinical trials conducted outside Japan, indicating that ET-743 can be an effective treatment option.

To make ET-743 available for Japanese patients and health care professionals for treatment of malignant soft tissue sarcoma, an area of high unmet medical needs, Taiho will strive to obtain marketing approval of ET-743 in Japan.

Malignant soft tissue sarcoma is an intractable malignancy which develops in the soft tissues (muscles, connective tissues, fat, blood and lymph vessels, etc.) of the body. In Japan, annual incidence rate is 2 to 3 cases per 100,000 population, and it is an orphan disease with an estimated patient number of 3,000^*2.

ET-743 is a novel antitumor agent developed by PharmaMar, originally isolated from the Caribbean tunicate Ecteinascidia turbinata and now produced synthetically. It binds to the minor groove of DNA, interfering with cell division, genetic transcription processes and the DNA repair machinery, and its antitumor activity affects the tumor microenvironment as well. Under the product name Yondelis_®, it was first approved by the European Medicines Agency in September 2007 for the treatment of advanced soft tissue sarcoma, and in October 2009 for use in combination with pegylated liposomal doxorubicin for relapsed platinum-sensitive ovarian cancer patients. Currently, Yondelis_® is approved and marketed in 80 countries worldwide, including EU countries, Russia, Korea, Canada, etc.

PharmaMar is a subsidiary of the Zeltia Group (Spanish Stock Exchange symbol: ZEL), and a world-leading biopharmaceutical company committed to advancing the treatment of cancer through the discovery and development of new marine-derived medicines.　The Zeltia Group has been quoted on the Spanish Stock Exchange since 1963, and is based in Madrid, Spain.

*1: Presence of fusion genes and tumor specific chromosomal translocations have been reported in some malignant soft tissue sarcomas. Chromosomal translocation is when chromosomes break and the fragments fuse to other chromosomes. It is thought that the fusion genes occurring from this chromosomal translocation might be the cause of malignancies.

*2: Calculated by subtracting 2,000 "mesothelioma" patients from the 5,000 "malignance of mesothelioma and soft tissue" patients, referencing the MHLW Patient Survey (2008).