A prospective real-world study of eribulin for HER2-negative recurrent breast cancer patients: final results

Abstract

Abstract Background Two global phase 3 trials (301 trial of first- or second-line eribulin, EMBRACE of third- or later-line eribulin) were carried out during development of eribulin for breast cancer treatment. In this post marketing observation study in Japan, efficacy and safety of eribulin in metastatic breast cancer patients were examined. Additionally, the results were compared with that of phase 3 trials. Method We conducted a prospective study in patients with inoperable or recurrent HER2-negative breast cancer. We enrolled a similar number of patients receiving eribulin as first- or second-line therapy (early line) and those receiving eribulin as third- or later line therapy (later line), and followed the patients for two years (ClinicalTrials.gov Number: NCT02371174). For the overall survival and time to treatment failure, the estimated value of them were calculated by the Kaplan Meier method. The severity of adverse drug events was determined by CTCAE v 4.0. Results During September 2014 to February 2016, 651cases were registered at 182 facilities. In analysis set, 637 patients (319 patients of early line/317 patients of late line/1 patient of unknown) was median age of 62.7 (30 - 85) years. Performance status 0/1/2/3/4 was seen in 360/234/38/5/0 patients, respectively. Dose reduction were required in 33% of patients. The median overall survival (early line/late line) was 18.8 months/12.6 months, respectively, and median time to treatment failure was 4.4 months/3.8 months, respectively. Major side effects (early line/late line) were neutropenia (51%/56%), leucopenia (55%/57%), peripheral neuropathy (32%/22%). Grade 3≤ peripheral neuropathy was 2%. Conclusion The results of overall survival (18.8 months in early line, 12.6 months in later line) in this study is comparable to those of large phase 3 study (15.9 months in 301 trial, 13.1 months in EMBRACE). The incidence of Grade 3≤ peripheral neuropathy was lower than that of phase 3 trials.