ERBB2 and breast cancer: In HALT-D, we hypothesized that crofelemer would reduce diarrhea in patients with HER2-positive BC receiving HP and a taxane with or without carboplatin (THP/TCHP; the taxane being paclitaxel or docetaxel; where C was always combined with docetaxel rather than paclitaxel) in the neoadjuvant, adjuvant, or metastatic settings.