Phase 2 Study of Fulvestrant With and Without Entinostat in Postmenopausal Women With ER+ Advanced Breast Cancer

Preclinical data has demonstrated that entinostat (SNDX-275) can enhance fulvestrant sensitivity in hormone receptor-positive breast cancer in animal models. The addition of entinostat to fulvestrant will provide clinical benefit to patients with locally advanced or metastatic breast when compared to fulvestrant plus placebo. Also, based on previous data, patients exposed to entinostat who demonstrate an elevated level of protein lysine acetylation will have an improved efficacy outcome.