HER2DX pCR score for predicting pCR with deescalated neoadjuvant trastuzumab-pertuzumab for HER2-positive breast cancer

Patients with HER2-positive breast cancer who experience a pathologic complete response (pCR) after receiving neoadjuvant therapy have favorable survival outcomes. Predicting the likelihood of pCR may help optimize neoadjuvant therapy. In a diagnostic analysis of the phase 2 DAPHNe trial, the HER2DX assay was administered on baseline tumor biopsy specimens from 80 patients receiving neoadjuvant paclitaxel plus trastuzumab and pertuzumab for early-stage HER2-positive breast cancer. The HER2DX pCR likelihood score was significantly associated with pCR (pCR rates 92.6%, 63.6%, and 29.0% in the HER2DX high, medium, and low score groups, respectively). The authors conclude that these results suggest that the HER2DX assay may help to optimize escalation or deescalation of neoadjuvant therapy for early-stage HER2-positive breast cancer.