This randomized phase II trial studies how well fulvestrant with or without enzalutamide works in treating patients with estrogen receptor positive and HER2 negative breast cancer. 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 breast cancer.
Additional locations may be listed on ClinicalTrials.gov for NCT02955394.
See trial information on ClinicalTrials.gov for a list of participating sites.
PRIMARY OBJECTIVES:
I. Evaluate the rate of Preoperative Endocrine Prognostic Index (PEPI) score equal to 0 at 16 weeks post treatment for each of the two treatment arms separately.
SECONDARY OBJECTIVES:
I. To determine the percentage of progression-free survival (PFS), clinical response rate (by physical exam and breast imaging) after 16 weeks of therapy for the single drug arm and combination of enzalutamide/fulvestrant arm separately.
II. To assess the association between PEPI score and the clinical outcomes such as PFS and clinical response for all the subjects.
III. To confirm the safety profile of the combination.
IV. To determine the extent of androgen receptor (AR) expression and signaling in breast tissue, to evaluate the effect of the drug(s) on the tumor, and to evaluate the relationship of these effects on clinical outcomes for the two arms separately.
OUTLINE: Patients are randomized to 1 of 2 arms.
ARM A: Patients receive fulvestrant intramuscularly (IM) on days 1, 15, and 28 of course 1 and every 4 weeks of subsequent courses. Courses repeat every 4 weeks in the absence of disease progression or unacceptable toxicity.
ARM B: Patients receive fulvestrant as in Arm A and 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, every 6 months for 2 years, and then yearly for 3 years.
Lead OrganizationUCHealth University of Colorado Hospital
Principal InvestigatorAnthony D Elias
