Diphenoxylate Completed Phase 2 Trials for Stage III Breast Cancer AJCC V7 / Stage IIIC Breast Cancer AJCC v7 / Stage II Breast Cancer AJCC v6 and v7 / Stage IIA Breast Cancer AJCC v6 and v7 / HER2/Neu-positive Breast Cancer / Stage IIIB Breast Cancer AJCC v7 / Breast Adenocarcinoma / Stage IIB Breast Cancer AJCC v6 and v7 / Stage IIIA Breast Cancer AJCC v7 Treatment