Immunotherapy for triple-negative breast cancer-State of the art

Background: Immune checkpoint inhibitors (ICPi) play an important role in the treatment of solid tumors.Objective: Within the scope of this review, an overview of the areas of application of ICPi in the primary and palliative treatment of breast cancer is given, taking clinical and predictive markers into account.Material and method: The current evidence is discussed based on the current study situation including the most important phase II/III studies.Results: In the neoadjuvant setting only pembrolizumab is currently approved for the treatment of triple-negative breast cancer (>= 2 cm and/or N1, regardless of the programmed death ligand 1, PD-L1 status). The addition of pembrolizumab is associated with both an increased pathologic complete remission (pCR) rate and an improved event-free survival (EFS). In the metastatic situation both atezolizumab in combination with nab-paclitaxel and pembrolizumab with a taxane or with carboplatin/gemcitabine are approved. While improved progression-free survival (PFS) was shown for both options, improved overall survival (OS) was demonstrated only for pembrolizumab. A prerequisite is PD-L1 positivity, which for atezolizumab is defined based on an immune cell (IC) score >= 1. For the use of pembrolizumab, the combined positive score (CPS) value must be >= 10.Conclusion: The ICPIs make a significant contribution to the optimization of systemic therapy in primary and metastatic triple-negative breast cancer.