Eisai Co., Ltd. (Headquarters: Tokyo, CEO: Haruo Naito, "Eisai") announced today that it has received approval in Japan for its in-house developed anticancer agent Halaven® (eribulin mesylate) as a treatment of patients with soft tissue sarcoma.

Halaven is the first and only single agent to demonstrate an overall survival (OS) benefit in a Phase III trial in patients with advanced, recurrent or metastatic soft tissue sarcoma (liposarcoma or leiomyosarcoma). Following approval for use in the treatment of inoperable or recurrent breast cancer in Japan, this marks the second indication for which Halaven has been approved based on a statistically significant extension of OS. In a Phase III clinical study (Study 309) in patients with locally advanced, locally recurrent or metastatic soft tissue sarcoma (liposarcoma or leiomyosarcoma) who had disease progression following standard therapies which must have included an anthracycline and at least one other additional regimen, Halaven demonstrated a statistically significant extension in the study's primary endpoint of OS over the comparator treatment dacarbazine.

1 The most common adverse reactions (incidence greater than or equal to 25%) in patients treated with Halaven in the study were neutropenia, fatigue, alopecia, nausea, and peripheral neuropathy, which was consistent with the known side-effect profile of Halaven. Furthermore, in a Phase II clinical study (Study 217) of Halaven in patients with advanced or recurrent soft tissue sarcoma who had received chemotherapy conducted within Japan, the results also suggested clinical efficacy for Halaven.

2 Soft tissue sarcoma is a collective term for a diverse group of malignant tumors that occur throughout the soft tissues (including fat, muscle, nerves, fibrous tissues and blood vessels) in the body. According to a patient survey conducted by Japan's Ministry of Health, Labour and Welfare, there are approximately 4,000 patients with soft tissue sarcoma in Japan.

In January 2016, Halaven was approved in the United States as a treatment of patients with unresectable or metastatic liposarcoma who have received a prior anthracycline-containing regimen, and applications seeking approval for use in the treatment of soft tissue sarcoma are currently under review in the EU, Switzerland, Russia, Australia, and Brazil. Halaven has been designated as an orphan drug for the treatment of soft tissue sarcoma in the United States and Japan. Halaven is a halichondrin class microtubule dynamics inhibitor with a distinct binding profile. Recent non-clinical studies showed that Halaven is associated with increased vascular perfusion and permeability in tumor cores.

3 Halaven promotes the epithelial state and decreases the capacity of breast cancer cells to migrate.

4 Halaven is currently approved for use in the treatment of breast cancer in approximately 60 countries including Japan and countries in Europe, the Americas and Asia. Through obtaining this additional approval, Eisai aims to enhance the clinical value of Halaven to contribute further toward addressing the diverse needs of, and increasing the benefits provided to, patients with cancer, their families, and healthcare providers.

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