Diagnostic HER2DX-guided Treatment for Patients wIth Early-stage HER2-positive Breast Cancer

"Patients with HER2DX high-risk disease:~* Neoadjuvant treatment:~ * High HER2DX pCR score: paclitaxel per 12 weeks + trastuzumab +/- pertuzumab per 4-5 cycles.~ * Medium HER2DX pCR score: carboplatin + paclitaxel per 12-18 (or docetaxel per 4-6 cycles) + trastuzumab +/- pertuzumab per 4-7 cycles.~ * Low HER2DX pCR score: standard of care neoadjuvant CT regimens and HER2 blockade at the investigator's choice.~* Adjuvant treatment:~ * pCR at surgery; Trastuzumab +/- pertuzumab up to a total of 18 cycles (including neoadjuvant and adjuvant therapy).~ * No pCR at surgery: T-DM1 per 14 cycles.~Patients with HER2DX low-risk disease:~* Neoadjuvant treatment: paclitaxel per 12 weeks + trastuzumab +/- pertuzumab per 4-5 cycles.~* Adjuvant treatment will be according to the pCR status at surgery:~ * pCR at surgery: trastuzumab or no adjuvant treatment.~ * No pCR at surgery: trastuzumab or T-DM1."

Patients randomized in ARM A will be treated with standard of care neoadjuvant CT regimens and HER2 blockade at the investigator's choice validated by national and/or international guidelines.