Treatment (Tx) patterns, efficacy and safety of eribulin for advanced and heavily pretreated breast cancer (ABC): Updated results from a single-center, real-world study.

e13118 Background: We evaluated the Tx patterns, efficacy and safety of eribulin for heavily pretreated ABC in real-world practice. Previous results were reported at the 2023 ASCO (e13118), updated results for longer follow-up and additional enrollment are presented here. Methods: Patients (pts) with ABC who had progression on anthracycline taxane Tx and received eribulin (1.4 mg/m 2 IV on Days 1 and 8 of a 21-day cycle) between April 2020 and October 2023 were enrolled. Response was evaluated using RECIST v1.1. Pts were considered as taxanes sensitive if taxanes treatment duration of last line use exceeds 6 months, otherwise were considered as taxanes resistant. Results: 89 pts were enrolled. Median (range) age was 54 (30–79) years; 80.9% had an Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0–1, and 40.4% pts had a median of 3 prior lines of chemotherapy. 67.4% of pts had Ki67 >30% and 46.0% had HR+/HER2− disease. 88.7% of pts had visceral metastasis. Eribulin was monotherapy in 30.3% of pts, and combined with bevacizumab, capecitabine, bevacizumab + capecitabine, and anti-HER2 agents in 28.1%, 9.0%, 3.4%, and 25.8%, respectively. The objective response rate was 22.5%; disease control rate was 84.3%. Median progression-free survival (PFS) overall was 6.0 (95% CI, 3.5–8.5) months (mo). Univariate analysis indicated pts with HER2+ disease had longer PFS than pts with HR+/HER2− or triple-negative BC (median, 13.5, 4.5, and 3.7 mo, respectively; P = 0.011; Table). Pts with Ki67 expression ≤30% had longer PFS than pts with Ki67 >30% (median, 8.0 vs. 4.0 mo; P = 0.02). Pts with grade I-II had longer PFS than pts with grade III (median, 10.5 vs. 4.0 mo; P = 0.003). Pts sensitive to Taxane had longer PFS than pts resistant to Taxane (median, 8.0 vs. 4.0 mo; P = 0.007). Among the 18 pts with a partial response, median PFS was 11.4 mo. The most common adverse events were leukopenia (44.9%), neutropenia (37.1%) and anemia (36.0%). Neurotoxicity was rare (6.7%). Conclusions: In this single-center study of pts with heavily pre-treated ABC in China, eribulin Tx resulted in favorable PFS irrespective of molecular subtype, with a manageable safety profile. In pts with a large tumor burden and a good PS, eribulin-based combinations may further improve outcomes. Table: see text