Atezolizumab for the treatment of triple-negative breast cancer

Triple-negative breast cancer (TNBC) is associated with poor prognosis and limited treatment options. However, TNBC is known to be more immunogenic compared to other breast cancer subtypes, with tumor-infiltrating lymphocytes playing an important prognostic and predictive role. Furthermore, TNBC has a higher level of programmed cell death-ligand 1 (PD-L1) expression. Therapeutic blockade of PD-L1 using atezolizumab is thus expected to activate and enhance tumor-specific T-cell responses, resulting in improved anti-tumor activity. Areas covered: This review summarizes the development and the impact of the PD-L1 inhibitor atezolizumab in advanced TNBC; it examines the mechanism of action, pharmacokinetics and the available preclinical and clinical data. Expert opinion: Atezolizumab, a novel immune checkpoint inhibitors targeting PD-L1, is an effective and well-tolerated treatment option for metastatic TNBC. In general, TNBC has a high unmet medical need, hence the clinical development of atezolizumab should continue, particularly for TNBC. Indeed, atezolizumab has the potential to substantially augment the therapeutic armamentarium for TNBC. This should lead to improved immunotherapeutic strategies and the enhancement of the outcome for this group of breast cancer patients.