HER2DX is a 27-gene prognostic (risk-score) and predictive (pathological complete response [pCR]-score) assay in early-stage HER2+BC based on clinical data and the expression of 4 gene signatures (immune, proliferation, luminal differentiation and HER2 amplicon). Here we aim to further validate the ability of HER2DX to predict pCR.
Standardized HER2DX was evaluated centrally on FFPE tumor biopsies from the BionHER study, in which patients(pts) with stage I-III HER2+BC were treated with neoadjuvant THPx16weeks; tumor biopsies were obtained pre-treatment(D1) and 8 days later(D8), following the loading-dose of HP, prior to adding paclitaxel. Primary aim was to test the ability of HER2DX pCR-score to predict pCR (ypT0/isN0). Secondary objective were to test the ability of HER2DX pCR-score to predict pCR independently of hormone receptor (HR) status. HER2DX was also evaluated at D8. Logistic regression and receiver-operator curve (ROC) analysis were assessed.
HER2DX was evaluated in 49 pts of 52 (94%). cT1-2 disease represented 85% of cases (mean tumor size was 29mm), cN0 59%, and 67% were HR+. Among them, 46 of 49 (94%) pts had undergone surgery to date. The overall pCR rate was 45.6% and the rate of both pCR and ypT1miN0 was 55%. The % of HER2DX low-, medium- and high-pCR groups was 30.6%, 40.8% and 28.6%, respectively. HER2DX pCR-score (as a continuous variable [CV]) was significantly associated with pCR (odds ratio [OR]=4.25, p=0.001). The pCR rates in HER2DX pCR-high, pCR-medium and pCR-low groups were 75.6%, 40% and 13.3% (-high vs -low OR=18.33, p=0.004), respectively. The AUC ROC of HER2DX pCR score (as a CV) and pCR status was 0.813. HR status was significantly associated with pCR score (OR=0.43, p=0.008). HER2DX pCR score was significantly associated with pCR independently of HR status (OR=3.89, p=0.010), which lost its statistically significance in the presence of HER2DX pCR-score (OR=0.87), p=0.756).
The 27-gene HER2DX genomic test predicts pCR following neoadjuvant THP in HER2+ BC. Updated data, including D8 HER2DX results, will be presented at the conference.
The authors.
Reveal Genomics, S.L.
All authors have declared no conflicts of interest.