LBA13 Predictive impact of biomarkers on pCR and survival after de-escalated neoadjuvant T-DM1 with or without endocrine therapy (ET) vs. trastuzumab+ET in HER2+/HR+ early breast cancer: WSG ADAPT TP trial

HER2+/HR+ EBC is a distinct entity associated with different molecular and clinical features compared to HER2+/HR- EBC. ADAPT TP showed promising pCR rates of 40% after only 4x T-DM1 +/- endocrine therapy (ET) which also corresponded to excellent 5y outcome. Optimal patient selection for de-escalation in HER2+/HR+ EBC is still an unsolved question.