207P A doublet metronomic chemotherapeutic regimen with oral vinorelbine and capecitabine (mNC) in patients with metastatic HER2-negative breast cancer: A prospective phase II study in China

Abstract

The long-term efficacy of oral metronomic vinorelbine + capecitabine (mNC) in the treatment of Chinese patients with HER-2 negative metastatic breast cancer (MBC) stays unclear. Thus, we conducted a phase II trial to assess the efficacy and safety of mNC in patients with HER-2 negative MBC in China. The eligible patients with HER2-negative MBC received oral metronomic vinorelbine 40 mg on day 1, day 3, day 5 every week and capecitabine 500mg three times daily (tid) after meals every 3 weeks until disease progression or unacceptable toxicity occurred, or withdraw of consent. The primary endpoint was 1-year progression-free survival (PFS) rate. Objective response rate (ORR) (complete and partial response [CR + PR]) and disease control rate (DCR) (CR + PR + stable disease [SD]), clinical benefit rate (CBR) (CR + PR + SD ≥ 6 months) and toxicities comprised the secondary endpoints. Analyses were carried out on the intention-to-treat (ITT) population. The Kaplan-Meier plot was utilized to create median PFS plots. A log-rank test was utilized to compare PFS between the two groups. Univariable Cox proportional regression analysis was conducted to assess the association between various patients or tumor characteristics and disease progression. 29 patients with HER2-negative MBC were enrolled. 17 patients received mNC as first-line chemotherapy , 12 patients received mNC as second-line and 1 patient received mNC as > second-line. The median follow-up time was 25.4 months. The CBR, ORR and DCR were 62.1%, 31.0% and 96.6%, respectively. The mPFS was 12.5 months (range, 1.1-28.1). 1-year PFS rate was 54.1%. Subgroup analysis showed CBR was 64.6% and 58.3% in first-and second-line subgroups, respectively. The mPFS was 15.5 months for first-line and 11.2 months for second-line subgroup. 1-year PFS rate was 65.2% for first-line and 41.6% for second-line subgroup. The most common grade 3/4 AEs included neutropenia (10.3%) and nausea/vomiting (6.9%). A doublet metronomic chemotherapeutic regimen with oral mNC is a well-tolerated and effective anti-tumor regimen for HER2-negative MBC in China.