Diarrhea Prevention and Prophylaxis With Crofelemer in HER2 Positive Breast Cancer Patients

Various anti-diarrheal agents, such as loperamide, codeine, octreotide, are available for diarrhea management, but few are used in the prophylactic setting and none provide a targeted approach for treating chemotherapy induced diarrhea (CID). Pre-clinical studies have suggested that blocking EGFR results in excess chloride secretion and thus diarrhea. Crofelemer is an extract from the blood red bark of Croton lechleri that inhibits luminal chloride efflux by blocking the calcium activated chloride channel (CaCC) and cystic fibrosis transmembrane regulator (CFTR) chloride channels. Due to its size and polarity, it acts only luminally and is not systemically absorbed. It is currently FDA approved for use in preventing diarrhea in HIV/AIDS patients on anti-retroviral therapy.