The PROMISE Study: Duavee in Women With DCIS

The main purpose of this study is to determine if taking the study drug, conjugated estrogens/bazedoxifene (Duavee®) causes any changes in the proliferation markers within the breast tissue of the study subjects. The study drug is approved by the US Food and Drug Administration in healthy postmenopausal women to treat certain symptoms of menopause such as hot flashes. Since it is not approved in women with DCIS, its use in this study is experimental. This study will also look at whether taking the study drug causes any significant or undesirable side effects in women with DCIS. The researchers hope that this study will help them determine if taking the study drug is safe in women taking DCIS and if it can possibly reduce the risk of developing breast cancer in women with DCIS.

PRIMARY OBJECTIVES; • To determine if CE/BZA reduces proliferation as measured by Ki-67 protein expression Secondary Objectives: * To determine if CE/BZA modulates expression of ERα, progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER-2). * To determine if CE/BZA modulates a previously validated set of epithelial markers of progression. * To determine if TSECs will restore expression of the stromal marker CD36 and repress pro-tumorigenic ECM proteins and soluble factors. * To determine if a short intervention with CE/BZA results in any difference in Quality of Life (QOL) as it relates to menopausal symptoms in postmenopausal women with DCIS. * To determine if a short intervention with CE/BZA has a favorable side effect profile compared with other endocrine therapy interventions using the validated Breast Cancer Prevention Trial Eight Symptom Scale (BESS) questionnaire. Exploratory Objectives * To determine if CE/BZA alters expression of estrogen-modulated genes and elicits novel ER dependent-gene signatures in breast epithelium * To demonstrate that CE/BZA does not upregulate Anterior Gradient 2 (AGR2), a marker of ERα agonist activity. * To determine if CE/BZA will modulate some aspects of immune function as measured by a switch to a M2-type pro-tumorigenic macrophage signature and an immunosuppressive T cell signature. * To determine if a short intervention with CE/BZA alters expression of estrogen-modulated genes and elicits novel ER dependent-gene signatures in the breast stroma. * To determine if CE/BZA affects plasma concentrations of BZA in patients with the UGT1A1\*28 gene polymorphism. OUTLINE: Patients are randomized to 1 of 2 treatment arms. ARM I: Patients receive conjugated estrogens/bazedoxifene orally (PO) once daily (QD) for 28 +/- 7 days in the absence of disease progression or unacceptable toxicity. Patients then undergo surgery. ARM II: Patients receive placebo PO QD for 28 +/- 7 days in the absence of disease progression or unacceptable toxicity. Patients then undergo surgery.