GSE139050
Immuno-priming with bevacizumab: durvalumab plus bevacizumab after prolonged exposition to bevacizumab in breast cancer
Purpose: To study the potential priming benefit of bevacizumab from subsequent immunotherapy (durvalumab) in advanced breast cancer patients Methods: We tested this hypothesis by adding durvalumab after progression to maintenance single-agent bevacizumab treatment in advanced HER2-negative patients (average 3 treatment lines). In order to study the potential priming benefit, patients had to experience disease progression while on bevacizumab maintenance prior to entering the trial. In addition, we sought to find traits in peripheral-blood mononuclear cells (PBMCs) and tumor biopsies that informed about this immuno-priming, in an attempt to search for novel biomarkers of efficacy of the combo and obtain a better understanding of the biology of this clinical scenario. Results: Patients that experienced clinical benefit, compared with the remaining patients, displayed a lymphocyte pattern in PBMCs consisting on increased T-effector subpopulations (CD4- and CD8- effector and effector-memory) and decreased immunosuppressive T-regulatory cells. Gene-expression studies in tumor samples showed a congruent pattern, with increased T-effector and memory T cell signatures in responders, and increased T-regulatory and decreased active dendritic cells in non-responders. These events were observed in patients that displayed vascular normalization features as a result of previous bevacizumab, supporting the immuno-priming effects of this strategy. Overall design: mRNA profiles of 3 advanced breast patient samples that do not respond to therapy (non-Responders) and 3 patient samples that respond to therapy (Responders) samples were generated by deep sequencing.  Differential gene expression (DGE) analyses were performed.