Role of Immunotherapy in Early- and Late-Stage Triple-Negative Breast Cancer

For women with triple-negative breast cancer, the addition of pembrolizumab to chemotherapy has become a standard of care in the early-stage and first-line metastatic setting. However, many questions persist. Different chemotherapy backbones and sequencing strategies have been evaluated, but evidence supporting the superiority of one over the other is weak. Although many have been investigated, programmed cell death ligand 1 (PDL1) is the only approved biomarker. Since immunotherapy has been associated with potentially severe and permanent toxicities, the identification of better predictive biomarkers is essential. New strategies are needed to increase the proportion of patients who might benefit from immunotherapy.