Atezolizumab in the treatment of metastatic triple-negative breast cancer.

Triple-negative breast cancer (TNBC) accounts for approximately 10%-15% of all diagnosed breast cancers and is associated with an aggressive natural history and poor clinical outcomes. Immunotherapy using immune checkpoint inhibitors has emerged as an effective therapeutic option for TNBC. The results of the IMpassion130 trial have recently led to the approval of the combination of atezolizumab and nab-paclitaxel in the first-line treatment of patients with unresectable locally advanced or metastatic, PD-L1-positive TNBC. This article summarizes the clinical development and ongoing research on atezolizumab in the treatment of metastatic TNBC. Results of atezolizumab monotherapy trials and data from combination studies with chemotherapy in the advanced setting are reviewed, with special focus on the design, methods, and key findings of the IMpassion130 trial. The approval of atezolizumab plus nab-paclitaxel represents an important advance in the treatment of metastatic TNBC. This combination has a favorable risk-benefit profile and is associated with clinically meaningful outcomes. However, further research is needed to identify better predictive biomarkers of response as well as novel immunotherapeutic strategies with atezolizumab and other anticancer drugs.