Preventive stRategy for IMMU132-relatED AEs in TNBC or Luminal Breast Cancer- PRIMED

The hypothesis of this study is that the prophylactic administration of loperamide (for diarrhea) and G-CSF therapies (for neutropenia) would avoid these undesirable effects when patients are treated with sacituzumab govitecan, thus decreasing the rate of dose reduction or discontinuation, and significantly improving patients' quality of life. The main objectives of this study are: Primary objective: \- To evaluate the incidence of diarrhea and neutropenia in patients with unresectable locally advanced or metastatic TNBC or Luminal breast cancer treated with sacituzumab govitecan in combination with loperamide and G-CSF. Secondary objectives: * To determine the safety and tolerability of the study regimen in this patient population. * To determine the efficacy of the study regimen in this patient population.