Reversing Therapy Resistance With Epigenetic-Immune Modification

Unique aspects of this study: This is the first study to look at the response of hormone therapy resistance breast cancer to epigenetic immune priming. It is also the first study to look at the combination of an Histone deacetylase (HDAC) inhibitor (vorinostat), an anti-estrogen (tamoxifen) and a PD-1 inhibitor, pembrolizumab in pre or postmenopausal patients with ER+ advanced breast cancer with progression on multiple prior therapies. Recent preclinical studies have further suggested that epigenetic priming may be even more effective in ER-negative tumors that do not respond to immune check point inhibitors or have low PD-1/PD-L1 expression. The goal of this study is to demonstrate that Vorinostat can increase PD-1 and PD-L1 expression. In a third arm the study will evaluate the role of epigenetic priming in tumors that are ER-negative.