Efficacy and safety of eribulin as a front-line treatment in patients with advanced breast cancer: The first large scale prospective real-world study in China

e13127 Background: Eribulin is a non-taxane microtubule inhibitor, which was approved for third-line treatment of advanced breast cancer (ABC) in China in 2019. However, efficacy and safety data for eribulin in Chinese patients with ABC are lacking, regardless of the therapy line. This study evaluated the efficacy, safety, and treatment pattern of eribulin in first- to third-line settings in Chinese patients with ABC. Methods: Patients with histologically confirmed ABC who had received ≤2 lines of prior treatment for metastatic disease were enrolled. Patients with HR+/HER2- ABC received eribulin monotherapy; those with HER2+ ABC received eribulin plus anti-HER2 targeted therapy, and those with metastatic triple-negative breast cancer (mTNBC) received eribulin plus immunotherapy/chemotherapy. The primary outcome was progression-free survival (PFS). Secondary outcomes included disease control rate (DCR) and safety. This study was approved by the SYSMH and SYSUCC Ethics Committee (approval No. 2020-KY-064). Results: In total, 160 patients were enrolled from 1 January 2021 to 31 December 2022 and 142 received study treatment. Eribulin was administered as first-line therapy in 41 (28.9%) patients, second-line therapy in 50 (35.2%), and third-line therapy in 51 (35.9%). The DCR was 71.6%; 55 patients (45.8%) had stable disease and 31 patients (25.8%) had complete or partial remission. The 6-month PFS rates (95% confidence interval [CI]) were: overall, 68.4% (58.0%, 76.8%); first-line eribulin, 75.4% (54.9%, 87.6%); HR+/HER2- ABC, 67.4% (53.8%, 77.7%); HER2+ ABC, 70.1% (38.5%, 87.6%); mTNBC, 69.5% (46.3%, 84.2%). PFS data were immature; the median (range) PFS was not reached with first-line eribulin and was 11.8 (3.3, 11.8) months with second-line eribulin. Subgroup analyses are shown in the Table; the 6-month PFS rate was 64.3% versus 74.0% in patients with versus without visceral metastases (p=0.25364). Common treatment-related adverse events (AEs) were hematological toxicities including leukopenia (9.5%), neutropenia (5.3%), and hypochromia (7.3%). There were no grade ≥3 AEs or AE-related treatment discontinuations. Conclusions: There was no significant difference in the efficacy analysis between the subgroup with visceral metastases and the subgroup without visceral metastases. Eribulin as first- or second-line chemotherapy is effective and has manageable toxicity in patients with ABC. Clinical trial information: NCT04683445 . [Table: see text]