Prediction of Benefit From Adjuvant Pertuzumab by 80-Gene Signature in the APHINITY (BIG 4-11) Trial.

Abstract in brief

• The study investigated whether the 80Gene Signature (80GS) could predict which early-stage HER2-positive breast cancer patients would benefit most from adding pertuzumab to standard therapy, finding that basal subtype tumors had worse invasive disease-free survival, while HER2 single-activated tumors showed a trend toward greater benefit from pertuzumab.
• The 80GS classified tumors into luminal, HER2, and basal types, with most luminal tumors showing a single activated pathway, and a significant portion of HER2 and basal tumors showing multiple activated pathways, but no overall difference in survival among subtypes except for the basal single subtype, which had worse outcomes.
• The findings suggest that the 80GS may help identify specific HER2-positive breast cancer subgroups that are more likely to benefit from dual anti-HER2 therapy with pertuzumab, especially in HER2 single-activated tumors, potentially guiding more personalized treatment strategies.