Kadcyla And Neratinib for Interception of HER2+ Breast Cancer With Molecular Residual Disease

This is a Phase 2 study for patients with resected Stage I-III HER2+ breast cancer with detected molecular residual disease (MRD+) following standard neoadjuvant and locoregional therapy delivered with curative intent. In this study Patients will be treated with neratinib in addition to their standard T-DM1 adjuvant therapy. Neratinib will be administered orally at a dose of 160 mg daily for up to 12 months, or until the time of clinical recurrence, discontinuation due to toxicity, or withdrawal of consent. This study will have two stages, stage 1 would enroll up to 8 participants to clear the Minimal Residual Disease (MRD) and Stage 2 will enroll up to 5 participants. The purpose of this study is to determine if this study population would have a better outcome from adding neratinib to their standard T-DM1 adjuvant therapy.