Pembrolizumab And Tamoxifen Among Women With Advanced Hormone Receptor Positive Breast Cancer And Esr1 Mutation

Pembrolizumab is a potent and highly selective humanized monoclonal antibody (mAb) designed to directly block the interaction between PD-1 and its ligands and enable the T cell to remain active and co-ordinate an attack on tumor cells. We hypothesise that the Clinical Benefit Rate (CBR) and progression free survival (PFS) of metastatic breast cancer patients who have ESR1 mutation will improve following administration of a combination of pembrolizumab and tamoxifen.