Recent findings from the #PATINA trial further confirmed the efficacy of combined targeted treatment in HER2+ER+ BC. We provide a better understanding of #drivers and #dynamics of HER2+ER+ tumour response, towards to the design of de-escalation or #escalation strategies.

The HighHigh group showed #dysfunctional immune infiltration and overexpression of #therapeutic #targets like #PAK4 at baseline. The LowLow group exhibited a #LuminalA phenotype by the end of treatment

Stratification based on Ki67 at Day14 and at surgery defined three response groups (Ki67 HighHigh, LowHigh, LowLow), with divergent tumour and stroma expression dynamics

We performed #RNAseq and #TIL assessment in serial biopsies from the NA-PHER2 trial. High #immune #infiltration and low #ER signalling at baseline correlated with #pCR, while #TP53 mutations associated with high Day14 #Ki67