Treatment patterns and clinical outcomes in chemotherapy-treated patients with HR+/HER2− metastatic breast cancer using real-world data in France and Germany

BACKGROUND: Limited real-world data exist on treatments for hormone receptor-positive/human epidermal growth factor receptor-2 negative (HR + /HER2 −) metastatic breast cancer (mBC) worldwide. We evaluated real-world survival outcomes and treatment patterns for patients with mBC who received chemotherapy (CT) in two European countries. METHODS: This retrospective cohort study analysed anonymised data from adult patients with HR + /HER2 − mBC, who initiated ≥ 1 CT at any line of therapy (LoT) on/after their diagnosis, from one site in France and two in Germany, between 01/01/2016 and 28/02/2023. Primary outcomes were overall survival (OS) and time to next treatment or death (TTNTD) by CT line. Additionally, treatment patterns were reported. RESULTS: The study evaluated data for 339 French and 157 German patients; median (interquartile range [IQR]) age at first CT: 62 (51–71) years (France), 57 (49–67) years (Germany). In France, the median (IQR) OS and TTNTD at first CT were 20 (8–40) and 5 (3–7) months, decreasing to 7 (3–15) and 3 (2–5) months at fourth line, respectively. In Germany, these outcomes were 24 (9–NA) and 6 (3–9) months at first CT, decreasing to 7 (2–NA) and 3 (1–8) months by fourth line, respectively. In France, 91% of patients received a second LoT, 71% a third, and 53% a fourth. The most frequent first LoT was CT only (45%), followed by endocrine therapy (ET) + cyclin dependent kinase 4/6 inhibitors (CDK4/6i; 32%). In Germany, 90% of patients received a second LoT, 71% a third, and 48% a fourth, with the most common first LoT being ET + CDK4/6i (34%), followed by other regimens (29%) and CT only (24%). CONCLUSIONS: Prognosis in patients with HR + /HER2 − mBC receiving CT treatment remains poor, with a median OS < 2 years. Patients typically receive CT as first-line therapy with ET and CDK4/6i received in subsequent treatment lines.