Eribulin as first- or second-line chemotherapy for advanced or metastatic HER2-negative breast cancer: A real-world prospective study

Abstract

Background: A global phase III study confirmed the effect of eribulin mesylate (ERI) as third- or later-line chemotherapy on overall survival (OS) for advanced or metastatic breast cancer. Meanwhile, in Japan, ERI can be used as first- or second-line. However, limited reports can be found on time to treatment failure (TTF) and/or OS for ERI as first- or second-line therapy comparing to late-line therapy in clinical practice. Methods: We conducted a prospective study in patients with inoperable or recurrent HER2-negative breast cancer starting in September, 2014. We enrolled a similar number of patients receiving ERI as first- or second-line therapy and those receiving ERI as third- or later-line therapy, and with follow-up planned for up to two years (ClinicalTrials. gov: NCT02371174). The data collected by November 2017 was analyzed. TTF and OS were estimated using the Kaplan-Meier method. Multivariate Cox regression was used to identify the factors influencing TTF and OS. Results: We analyzed 634 patients. The mean age (6standard deviation) was 59.6 years (611.0), and 157 patients (24.8%) had triple-negative breast cancer. Of these patients, 319 received ERI as first- or second-line therapy and 315 as third- or later-line therapy. The median TTF (95% confidence interval [CI]) was 135 (121-164) and 119 (106-128) days, and the median OS (95% CI) was 555 (475-628) and 383 (342-459) days for firstor second-line- and third- or later-line therapy, respectively. A history of radiation therapy, complication of diabetes, liver metastasis, ECOG performance status, blood hemoglobin and aspartate aminotransferase levels at baseline, triple-negative breast cancer, and development of peripheral neuropathy after ERI treatment were significant factors influencing both TTF and OS. Conclusions: Our real-world study showed patients with first- or second-line therapy of ERI have longer OS and TTF than those in third- or later-line therapy. These results suggested that patients with first- or second-line therapy of ERI have the potential for similar or more favorable outcomes from the ERI treatment compared with patients with third- or later-line therapy of ERI.