Data of Programmed death-ligand 1 expression and VEGF: Nivolumab Plus Bevacizumab, Paclitaxel For HER2-Negative Metastatic Breast Cancer (WJOG9917BTR)
NEWBEAT was a phase 2, multicenter, single-arm trial that sought to evaluate the efficacy and safety of first-line triple therapy comprising nivolumab, bevacizumab, and paclitaxel in patients with HER2-negative advanced metastatic or inoperable recurrent BC. The purpose of the accompanying biomarker study (WJOG9917BTR) was to explore potential biomarkers of the efficacy and toxicity of triple therapy in patients with HER2-negative mBC.
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The patients enrolled in NEWBEAT were given an explanation of the accompanying biomarker study and provided informed consent for the biomarker analysis. The investigators collected tumor tissues (archival tissue or biopsy of metastatic site) and blood samples from consenting patients. Peripheral blood mononuclear cells and serum samples were collected at pretreatment, cycle 1 day 8, cycle 2 day 1, cycle 3 day 1, and cycle 8 day 1, or at the time of nivolumab discontinuation, and at the time of disease progression. Moreover, the investigators could collect samples when an immune-related adverse event occurred. Tumor tissue samples were used to evaluate PD-L1 expression on tumor cells and immune cells using a Dako 28-8 immunohistochemistry assay and on immune cells using a VENTANA SP142 immunohistochemistry assay. Peripheral blood mononuclear cells were used to analyze the immune cell profile and comprehensive gene analysis by flow cytometry and the nucleic acid digital counting method. The serum samples were used to measure the concentrations of cytokines, chemokines, and other surrogate proteins. Progression-free survival, overall survival, and response were analyzed in association with the biomarker data using the Kaplan–Meier method, log-rank tests, Cox proportional hazards model, and logistic model regression analysis as appropriate.