Circulating Tumor DNA in HER2-Amplified Breast Cancer: A Translational Research Substudy of the NeoALTTO Phase III Trial

In the neoadjuvant treatment (NAT) setting, dual HER2-targeted therapy is associated with increased pathologic complete response (pCR) rates compared with each therapy alone. Biomarkers allowing to predict treatment response during NAT are needed. We aim to evaluate whether circulating tumor DNA (ctDNA) is associated with response to anti-HER2-targeted therapy.Plasma DNA collected before NAT, at week 2, and before surgery from patients enrolled...