Time trends in real-world treatment patterns and survival in patients diagnosed with de novo HER2+ metastatic breast cancer: an analysis of the SONABRE registry

Abstract

Abstract Purpose The aim was to determine whether the real-world first-line progression-free survival (PFS) of patients diagnosed with de novo human epidermal growth factor receptor 2 positive (HER2+) advanced breast cancer (ABC) has improved since the introduction of pertuzumab in 2013. Methods Included were patients systemically treated for de novo HER2 + ABC in ten hospitals in 2008–2017 from the SONABRE Registry (NCT-03577197). First-line PFS in 2013–2017 versus 2008–2012 was determined using multivariable Cox proportional hazards modelling. First-given systemic therapy and the use of locoregional therapy within the first year following diagnosis were determined per period of diagnosis. Results Median and five-year PFS were 26.6 months and 24% in 2013–2017 (n = 85) and 14.5 months and 10% in 2008–2012 (n = 81) (adjusted HR = 0.65, 95%CI:0.45–0.94). Of patients diagnosed in 2013–2017 versus 2008–2012, 85% versus 60% received HER2-targeted therapy and 59% versus 0% pertuzumab-based therapy as first-given therapy. Respectively 27% and 23% of patients underwent locoregional breast surgery, and 6% and 7% surgery of a metastatic site during the first year following diagnosis. Conclusion The prognosis of patients with de novo HER2 + ABC has improved considerably. Since 2013 one in four patients were alive and free from progression on first-given therapy for at least five years.