Endocrine therapy with fulvestrant has shown synergistic antitumor effects with some chemotherapy drugs in vitro. This study evaluated the efficacy and safety of fulvestrant with vinorelbine in patients with hormone receptor positive (HR+)/human epidermal growth factor receptor-2-negative (HER2−) recurrent or metastatic breast cancer.

Patients were intramuscularly administered fulvestrant 500 mg (day 1 per cycle for 28 days) and oral vinorelbine (60 mg/m² on days 1, 8, and 15 of each cycle). The primary endpoint was progression-free survival (PFS). Secondary endpoints included overall survival, objective response rate, disease control rate, duration of response, and safety.

A total of 38 patients with HR+/HER2− advanced breast cancer included in the study were followed up for a median time of 25.1 months. The overall median PFS was 9.86 months [95% confidence interval (CI) 7.2–23.13], and the median PFS of the first-line and the second-line treatment population was 20.73 months (95% CI 9.82 to NR) and 4.27 months (95% CI 3.68 to NR), respectively. Most adverse events reported were of grade 1/2, and none were of grade 4/5.

This is the first exploratory study of a fulvestrant and oral vinorelbine regimen in the treatment of HR+/HER2− recurrent and metastatic breast cancer. The combination chemo-endocrine therapy was efficacious, safe, and promising for patients with HR+/HER2− advanced breast cancer.