This phase II trial studies how well fulvestrant and enzalutamide work in treating patients with estrogen receptor positive and HER2 negative breast cancer that has spread to other places in the body. Drugs used in chemotherapy, such as fulvestrant, work in different ways to stop the growth of tumor cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Androgen can cause the growth of breast cancer cells. Hormone therapy using enzalutamide may fight breast cancer by blocking the use of androgen by the tumor cells. Giving fulvestrant and enzalutamide may work better in treating patients with estrogen receptor positive and HER2 negative breast cancer.
Study sponsor and potential other locations can be found on ClinicalTrials.gov for NCT02953860.
PRIMARY OBJECTIVES:
I. To determine the clinical benefit rate (complete and partial response plus stable disease for 24 weeks) of the combination of enzalutamide/fulvestrant.
SECONDARY OBJECTIVES:
I. To confirm the safety profile of the combination.
II. Response rate (complete and partial response) at 24 weeks, progression-free survival (PFS) and % of patients remaining free from progression at 12 and 24 weeks.
III. To obtain serial biopsies of breast cancer pretreatment, during treatment and at time of tumor progression in order to determine the extent of androgen receptor (AR) expression and signaling in breast tissue, to evaluate the effect of enzalutamide on the tumor, and to evaluate the relationship of these effects on clinical outcomes.
OUTLINE:
Patients receive fulvestrant intramuscularly (IM) on days 1, 15, and 28 of course 1 and then on day 1 of subsequent courses. Patients also receive enzalutamide orally (PO) once daily (QD). Courses repeat every 4 weeks in the absence of disease progression or unacceptable toxicity.
After completion of study treatment, patients are followed up at 30 days.
Lead OrganizationUCHealth University of Colorado Hospital
Principal InvestigatorAnthony D Elias
