Purpose of review: There have been recent new developments in the treatment of breast cancer that over-expresses HER2 (ERRB2/HER2 positive) and the mechanistic understanding of trastuzumab response. We review these findings and reflect on how they may influence the next generation of clinical trials in this breast cancer subtype.
Recent findings: Two recent trials in the neoadjuvant setting report that treatment with dual anti-HER2 agents was superior, in terms of rates of pathological complete response, to trastuzumab alone. Recent data also highlight that HER2 positive disease is biologically different according to estrogen receptor status and for long lasting clinical remissions, anti-HER2 therapy also seems to require an effective adaptive immune response.
Summary: We are currently in a very exciting era for therapeutic approaches in HER2 positive disease. Recent data suggest that intensive chemotherapy regimens may not be required for some women if we can determine the most potent combinations of signal inhibitors. We also propose that different clinical trials may need to be designed for HER2 positive breast cancer according to estrogen receptor status and consider incorporating immunotherapeutic approaches.