Checkpoint Inhibitor Therapy for Metastatic Triple-Negative Breast Cancer

Of the breast cancer subtypes, triple-negative breast cancers (TNBCs) are characterized by immune activation and infiltration and more commonly express biomarkers associated with response to immunotherapy. Checkpoint inhibitor therapy has shown promising activity in metastatic TNBC. In this review, the clinical development of checkpoint inhibitors in the treatment of metastatic TNBC will be discussed, including clinical outcomes with monotherapy and combination therapy regimens, biomarkers that may predict for benefit, and future directions in the field.