[Efficacy and safety of eribulin for metastatic breast cancer patients]

In the EMBRACE trial, eribulin was reported to significantly increase overall survival compared to treatment of the physician 's choice when given to patients with recurrent or metastatic breast cancer who had received prior treatment, including an anthracycline and a taxane. In April 2011, eribulin was approved in Japan for the treatment of inoperable or recurrent breast cancer. In this article, we report on the efficacy and safety of eribulin in cases we encountered. Twenty patients with advanced and recurrent breast cancer were administered eribulin in our hospital during the period from August 2011 to December 2012. The median age was 62 years(range, 42-76 years); 16 patients had the estrogen receptor(ER)(+)/human epidermal growth factor receptor 2(HER2)(-)subtype, whereas 4 patients had the triple-negative subtype. Following recurrence, the median number of chemotherapy regimens was 3(range, 0-5). Regarding the antitumor effects of eribulin, no cases showed complete response(CR), 5 cases showed partial response(PR), and 10 cases showed stable disease(SD); therefore, the response rate(CR+PR)was 25% and the clinical benefit rate(CR+PR+B6-month SD)was 35%. Median progression free survival was 146 days, and median overall survival was 482 days. In terms of adverse events(AEs), observed cases of hematotoxicity were of neutropenia(75%), leucopenia(75%), and anemia(80%). Cases of Grade 3 hematotoxicity or higher were of neutropenia(40%), leucopenia(20%), and febrile neutropenia(1 case, 5%). The observed non-hematotoxic AEs were peripheral neuropathy(30%)and general malaise(35%), although none were of Grade 3 or higher. The therapeutic efficacy of eribulin in the present study was relatively better than that in previous reports(EMBRACE trial, Japan Domestic 221 trial). The frequency of Grade 3 or higher AEs was low, and the drug was well tolerated. We believe that eribulin is a novel drug that provides therapeutic efficacy while maintaining quality of life(QOL).