A phase II study of a doublet metronomic chemotherapy regimen consisting of oral vinorelbine and capecitabine in Chinese women with HER2‐negative metastatic breast cancer

BACKGROUND: This single‐arm prospective phase II trial was performed to assess the efficacy and safety of the dual oral metronomic vinorelbine and capecitabine (mNC) regimen in women with HER2‐negative metastatic breast cancer (MBC) in China. METHODS: The mNC regimen was administered to the enrolled cases, including oral vinorelbine (VNR) 40 mg three times weekly (on days 1, 3 and 5 every week) and capecitabine (CAP) 500 mg three times a day, until disease progression or intolerable toxicity. The primary endpoint was the 1‐year progression‐free survival (PFS) rate. Secondary endpoints included objective response rate (ORR), disease control rate (DCR), clinical benefit rate (CBR) and treatment‐related adverse events (TRAEs). Stratified factors included treatment lines and hormone receptor (HR) status. RESULTS: Between June 2018 and March 2023, 29 patients were enrolled into the study. The median follow‐up time was 25.4 months (range, 2.0–53.8). In the entire group, the 1‐year PFS rate was 54.1%. ORR, DCR and CBR were 31.0%, 96.6% and 62.1%, respectively. The mPFS was 12.5 months (range, 1.1–28.1). Subgroup analysis revealed that ORRs were 29.4% and 33.3% in first‐ and ≥second‐line chemotherapy, respectively. ORRs were 29.2% (7/24) and 40.0% (2/5) for HR‐positive MBC and metastatic triple‐negative breast cancer (mTNBC), respectively. Grade 3/4 TRAEs were neutropenia (10.3%) and nausea/vomiting (6.9%). CONCLUSIONS: The dual oral mNC regimen showed very good safety features and improved compliance without loss of efficacy in both first‐ and second‐line treatments. The regimen also reached an excellent ORR in the mTNBC subgroup.