Abstract: Methods for the treatment of HER2-positive breast cancer are provided by neoadjuvant administration of pertuzumab and trastuzumab in combination with anthracycline-based chemotherapy. In particular, the methods concerns the treatment patients with HER2-positive, locally advanced, inflammatory, or early-stage breast cancer by neoadjuvant administration of pertuzumab and trastuzumab following anthracycline-based chemotherapy, wherein the combined administration of pertuzumab and trastuzumab increases pathological complete response (pCR) relative to administration of trastuzumab as a single agent, without significant increase in adverse events, such as cardiac toxicity, relative to neoadjuvant anthracycline-based chemotherapy.