Dr Tung talks to ecancer at ASCO 2025 about the EA1181/CompassHER2 pCR trial she presented.

This study evaluated predictors of pathologic complete response (pCR) in patients with stage II/III HER2-positive breast cancer treated with neoadjuvant taxane, trastuzumab, and pertuzumab (THP).

Of 2,175 patients, the overall pCR rate was 44%, with significantly higher rates in HER2+/ER- tumours (63.7%) than in HER2+/ER+ tumours (32.4%). 

Lower oestrogen receptor expression and higher tumor grade were associated with higher pCR rates, while tumoir size and nodal involvement were not. 

The HER2DX genomic test score predicted pCR, regardless of ER status. The HER2DX test and ER level may help identify patients more likely to benefit from THP therapy.