Key clinical point: In postmenopausal women with estrogen receptor-positive (ER+) human epidermal growth factor receptor 2-positive (HER2+) advanced or metastatic breast cancer (BC), 500 mg fulvestrant (F500) with or without anti-HER2 therapy prolonged the time to treatment failure (TTF) in first- and second-line settings and improved the overall survival (OS) outcomes in those who received chemotherapy-free initial systemic therapy and required longer time to chemotherapy (TTC).
Major finding: F500 improved TTF in the first- and second-line vs third- or later-lines of therapy (6.6 vs 3.7 months; P = .014) and OS in patients who received chemotherapy-free initial systemic therapy and had TTC ≥ 3 years vs < 3 years (hazard ratio 0.32; P = .001).
Study details: This study analyzed 94 postmenopausal women with ER+/HER2+ advanced or metastatic BC from the SAFARI study who received F500 with or without anti-HER2 therapy.
Disclosures: This study was sponsored by Japan Breast Cancer Research Group and AstraZeneca. Several authors declared ties with various sources, including the funding agencies.
Source: Masuyama M et al. Fulvestrant with or without anti-HER2 therapy in patients in a postmenopausal hormonal state and with ER-positive HER2-positive advanced or metastatic breast cancer: A subgroup analysis of data from the Safari study (JBCRG-C06). Cancer Med. 2023 (Aug 1). doi: 10.1002/cam4.6390