Atezolizumab in the treatment of patients with breast cancer

Abstract

Immunotherapy is a modern method of treatment which is being tested in breast cancer patients. The first approved drug in this group was atezolizumab introduced for the treatment of patients with locally advanced and inoperable or metastatic triple-negative breast cancer (TNBC) with expression of programmed death receptor type 1 (PD-L1) on immunologic cells (IC) of ≥1%, who had not received prior chemotherapy for advanced disease. The results of the registration study IMpassion130 indicated that atezolizumab improved patient outcomes when used in combination with nab-paclitaxel. This article summarizes the most important analyzes of that study. The necessity to use the validated VENTANA SP142 assay to assess PD-L1 expression, which is necessary for the qualification of patients for this therapy, was emphasized. Additionally, the available data on the first results of the studies in patients with early TNBC as well as with human epidermal receptor type 2 (HER2)-positive and estrogen receptor (ER)-positive HER2-negative cancers treated with atezolizumab are discussed.