A Real-World Efficacy of Nab-Paclitaxel Monotherapy in Metastatic Breast Cancer

Purpose We aimed to assess the real-world efficacy of nab-paclitaxel in metastatic breast cancer patients. Materials and Methods This is a retrospective study performed in two tertiary referral hospitals in Korea. Patients with metastatic breast cancer treated with nab-paclitaxel (Abraxane) between March 2016 and March 2020 were enrolled. Results A total of 102 patients with metastatic breast cancer were included. Patients were heavily pre-treated with a median of four prior lines of chemotherapy (5 lines when including endocrine therapy in hormone-receptor-positive patients), and 66 patients (64.7%) were exposed to taxanes in the metastatic setting. According to St. Gallen molecular subtypes, 36 patients (35.3%) were luminal A, 28 (27.5%) were luminal B, 18 (17.7%) were human epidermal growth factor receptor 2-positive and 20 (19.6%) had triple-negative disease. Fifty patients (49.0%) were treated with a 3-weekly regimen (260 mg/m2 on day 1 every 3 weeks), and 52 (51.0%) were treated with a weekly regimen (100 mg/m2 every week). Objective response rate was 22.9%. After a median follow-up of 22.0 months, median progression-free survival (PFS) was 4.0 months (95% confidence interval [CI], 2.6 to 4.8) and median overall survival was 8.7 months (95% CI, 7.5 to 11.2). Patients treated with weekly regimen had longer PFS compared to 3-weekly regimen (5.5 vs. 2.3 months, p < 0.001). Multivariate analysis revealed the treatment regimen as an independent prognostic factor for PFS. There was no grade 3 or 4 hypersensitivity reaction. Conclusion This real-world data shows that nab-paclitaxel is a reasonable treatment option in heavily pre-treated and/or taxane-exposed metastatic breast cancer patients.