Eisai Presents Results of Post Hoc Analysis of Eribulin Mesylate (HALAVEN) at the European Society for Medical Oncology (ESMO) Congress 2022

Analysis Evaluates Efficacy of Eribulin in Metastatic HER2-low Breast Cancer Across Three Clinical Studies

TOKYO, Sep 12, 2022 - (JCN Newswire) - Eisai Co., Ltd. announced today results from a post hoc analysis of three randomized, pivotal, Phase 3 studies (EMBRACE trial/Study 305, Study 301 and Study304) evaluating the efficacy of eribulin mesylate (marketed as HALAVEN) versus other chemotherapies (Treatment of Physician's Choice [TPC], capecitabine, and vinorelbine, respectively) in patients living with metastatic breast cancer (mBC) whose tumors have low or no HER2 expression. These data were presented as a poster (Presentation: #259P) at the European Society for Medical Oncology (ESMO) Annual Meeting (#ESMO22), held virtually and in-person in Paris, France from September 9-13, 2022.

The HER2-low breast cancer subtype is a newly defined subset consisting of tumors that would have previously been considered HER2-negative based on an immunohistochemistry (IHC) assay and an in situ hybridization (ISH) assay. HER2-low tumors express low amounts of the HER2 protein, but not enough to be considered HER2-positive. HER2-low is defined as an IHC of 1+ or 2 with a negative ISH. Of the approximate 288,000 new cases of female breast cancer expected to be diagnosed in the U.S. in 2022,(1) it is estimated that approximately 80-85% of patients would previously have been considered to have the HER2-negative subtype. Of those patients, about 60% would now be considered to have the HER2-low subtype.(2)

"In this post-hoc analysis, the outcomes seen in mBC patients whose tumors are considered HER2-low are consistent with the results of the three pivotal Phase 3 clinical trials," said Dr. Takashi Owa, Chief Scientific Officer, Senior Vice President, Eisai Co., Ltd. "As the oncology community's understanding of mBC continues to evolve, it's important that we continue to evaluate the role of existing therapies in new contexts to contribute to the body of knowledge that is available to health care professionals."

(1) National Institutes of Health, National Cancer Institute website, "Cancer Stat Facts: Female Breast Cancer": https://seer.cancer.gov/statfacts/html/breast.html
(2) U.S. FOOD & DRUG ADMINISTRATION website, "FDA Approves First Targeted Therapy for HER2-Low Breast Cancer": bit.ly/3xc0N7q

For more information, visit www.eisai.com/news/2022/pdf/enews202266pdf.pdf.

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Eisai Co., Ltd.
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Source: Eisai
Sectors: BioTech