Preoperative Fulvestrant With or Without Enzalutamide in ER+/Her2- Breast Cancer

Inclusion Criteria

• •ER+ Her2- breast cancer
• •Stage at least T2 or greater
• •Planned to get local surgery
• •Postmenopausal, or if pre- or peri- menopausal, then will need to have concurrent ovarian suppression.
• •At least 18 years of age
• •Not on anticoagulants
• •PS 0-2
• •Able to swallow study drug and comply with study requirements
• •ANC \>1000/uL, platelets \>75,000/uL at screening visit
• •Total bilirubin \< 1.5 times upper limit of normal (ULN) at the screening visit unless an alternate nonmalignant etiology exists (eg, Gilbert's disease)
• •Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) \< 3 times ULN or \< 5 times ULN if patient has documented liver metastases
• •Creatinine \< 1.5 times ULN
• •INR \< 1.5 times ULN, or if on warfarin, can safely transition off for biopsy
• •Willing to donate blood for research at 4 time points
• •Willing to undergo core biopsies for research at study entry and at \~4 weeks.
• •Willing to donate tissue to research from the surgical specimen
• •Written informed consent obtained prior to biopsies and blood samples