Addition of atezolizumab to carboplatin significantly improves survival of patients with metastatic triple-negative breast cancer: TBCRC 043 phase 2 randomized clinical trial

A phase 2 randomized clinical trial was conducted in six centers from August 2017 to June 2021. Patients with metastatic TNBC were randomized to receive carboplatin AUC 6 alone or with atezolizumab 1200 mg every three weeks until disease progression or unacceptable toxicity with a three-year duration of follow-up.The primary endpoint was investigator-assessed progression-free survival (PFS). Secondary endpoints included overall response rate (ORR), clinical benefit rate (CBR) and overall survival (OS). Other objectives included correlation of response with tumor PD-L1 levels, tumor-infiltrating lymphocytes (TILs), tumor DNA-seq and RNA-seq biomarkers, TNBC subtyping and multiplex analyses of immune markers. RNA-seq and DNA-seq was performed on pre-treatment metastatic biopsies from patients enrolled on the trial.