Efficacy and safety of eribulin-based chemotherapy in patients with advanced breast cancer: A single-centre retrospective study.

e13121 Background: Eribulin, a nontaxane microtubule dynamics inhibitor, which was approved for the third-line treatment of advanced breast cancer (ABC) in China in 2019. This retrospective study aimed to assess efficacy and safety of Eribulin-based chemotherapy in ABC patients, especially for patients exhibiting HER2-0 and HER2-low status (immunohistochemistry IHC 1+ or IHC 2+with a negative in situ hybridization assay). Methods: This single-center retrospective study planned to include 126 ABC patients from January 2020 to December 2023. Enrolled participants received Eribulin either as monotherapy or in combination with other regiments such as anti-angiogenic therapy, PD-1 inhibitor, or alternative chemotherapy in clinical practice. The primary outcomes included progression-free survival (PFS) and safety assessments. Results: A total of 84 patients with ABC received Eribulin were enrolled. Patients' baselines were summarized as follows: The median age was 53.3 years (range 30.0–86.0 years). 53 (63.1%) patients were HER2-low while 40 (47.6%) patients were hormone receptor (HR) positive. 63.1% patients have received at least one line chemotherapy before the use of Eribulin. According to the K-M survival analysis, the median PFS was 6.0 (range 3.2-11.3) months for all patients. The median PFS was longer for patients received aromatase inhibitors (AI) for over 6 months than patients with AI naive (median 10.1 vs 6.6 months; p=0.192) in HR positive patients. Patients who received CDK4/6 therapy had longer PFS than patients (median 10.7 vs 6.6 months; p=0.38). There was a trend toward prolonged PFS in the HER2-0 group compared with HER2-low group (median 10.13 vs 6.03 months; p=0.154), although there was no significant difference. A nonsignificant improvement of PFS was observed in HR-/HER2-0 patients, compare with HR-/HER2-low patients (median 16.4 vs 4.7mo; p=0.21). Meanwhile the median PFS of HER2-0 and HER2-Low was similar in HR positive patients. The objective response rate was 35.5% in HER2-0 group and 30.2% in HER2-low group. In multivariate cox regression, Eribulin as first line treatment (HR, 4.028; 95% CI, 1.131-14.337) and HER2-0 (HR, 2.903; 95% CI, 1.257-6.702) showed prognostic values regarding PFS. Common grade 3 or 4 adverse events that were reported in more than 10% were neutropenia (41.6%) and leukopenia (26.2%). No treatment-related deaths were reported. Conclusions: This single-center study demonstrated encouraging efficacy and safety in the ABC patients treated with Eribulin. Significant PFS benefit was associated with Eribulin treatment in patients with HER2-0 compared with HER2-low. This study still needs longer follow-up to evaluate its efficacy more comprehensively.