Multiple Endocrinology Immune-Related Adverse Events (irAEs) Related to Pembrolizumab as Neoadjuvant Treatment in Two Cases of TNBC Patients: Case Reports and Literature Review

Pembrolizumab, an anti-PD-1 monoclonal antibody, showed promising results in the treatment of different types of solid tumors and generally an improvement in overall survival and patients’ outcome. However, as a drug that targets the immune system to enhance the anti-tumor response, it simultaneously increases the risk of autoimmune reactions, producing immune-related adverse events (irAEs). These irAEs might involve any body organ, and in some cases may lead to treatment discontinuation. In this article, we discuss two cases of triple-negative breast cancer (TNBC) patients, who developed irAEs during the course of neoadjuvant pembrolizumab, highlighting the mechanism of the reactions, possible clinical manifestations, and potential management.