Neoadjuvant Response-guided Treatment of HER2 Positive Breast Cancer

The purpose of this trial is to evaluate efficacy and toxicity of either the combination of docetaxel, trastuzumab sc and pertuzumab (arm A) or trastuzumab emtansin (arm B). Switch of therapy to the opposite treatment alternative is applicable in case of lack of response after two courses of treatment, or for medical reasons under exceptional circumstances (drug reaction, other medical conditions) at any point. After termination of the primary treatment follow-up for five years. A translational subprotocol is a mandatory part of the study protocol, with exception for the use of PET-CT evaluations.