The efficiency and safety of low-dose apatinib combined with oral vinorelbine in pretreated HER2-negative metastatic breast cancer

Background: Apatinib is an oral small-molecule tyrosine kinase inhibitor that blocks vascular endothelial growth factor receptor-2. Oral vinorelbine is a semisynthetic chemotherapeutic agent of vinorelbine alkaloids. Apatinib and oral vinorelbine have been proved to be effective in the treatment of metastatic breast cancer (mBC). At present, several small sample clinical trials have explored the efficacy of apatinib combined with oral vinorelbine in the treatment of mBC. Methods: This retrospective study included 100 human epidermal growth factor receptor-2 (HER2)-negative mBC patients who received low-dose apatinib (250 mg orally per day) plus oral vinorelbine until disease progression or intolerance during February 2017 and March 2023. The progression-free survival (PFS), overall survival (OS), objective response rate (ORR), clinical benefit rate (CBR), disease control rate (DCR), and safety were analyzed by SPSS 26.0 software and GraphPad Prism 8 software. Cox proportional hazards regression model for univariate and multivariate was used to identify factors significantly related to PFS and OS. Results: The median follow-up time for this study was 38.1 months. Among 100 patients with HER2-negative mBC, 66 were hormone receptor (HR)-positive/HER2-negative and 34 were triple-negative breast cancer (TNBC). The median PFS and OS were 6.0 months (95% CI, 5.2-6.8 months) and 23.0 months (95% CI, 19.9-26.1 months). There were no statistical differences in PFS (p = 0.239) and OS (p = 0.762) between the HR-positive /HER2-negative and TNBC subgroups. The ORR, CBR, and DCR were 21.0%, 58.0%, and 78.0%, respectively. Ninety-five patients (95.0%) experienced varying grades of adverse events (AEs) and 38.0% of patients for Grades 3-4. The most common Grades 3-4 AEs that we observed were neutropenia (30.0%) and leukopenia (25.0%). Conclusion: Low-dose apatinib combined with oral vinorelbine demonstrates potential efficacy and well tolerated for pretreated HER2-negative mBC.