Phase 2a, open-label, randomized, noncomparative study of BIIB021 in combination with exemestane in women with hormone receptor-positive, advanced metatatic breast cancer who have progressed on a nonsteroidal aromatase inhibitor

INTERVENTION: Product Name: Synthetic, small molecule, heat shock protein 90 (Hsp90) inhibitor Product Code: BIIB021 Pharmaceutical Form: Capsule* Other descriptive name: BIIB021 Concentration unit: mg milligram(s) Concentration type: equal Concentration number: 25‐ Product Name: Synthetic, small molecule, heat shock protein 90 (Hsp90) inhibitor Product Code: BIIB021 Pharmaceutical Form: Capsule* Other descriptive name: BIIB021 Concentration unit: mg milligram(s) Concentration type: equal Concentration number: 100‐ Product Name: Synthetic, small molecule, heat shock protein 90 (Hsp90) inhibitor Product Code: BIIB021 Pharmaceutical Form: Capsule* Other descriptive name: BIIB021 Concentration unit: mg milligram(s) Concentration type: equal Concentration number: 150‐ CONDITION: Advanced Metastatic Breast Cancer ; MedDRA version: 12.0 Level: LLT Classification code 10027475 Term: Metastatic breast cancer PRIMARY OUTCOME: Main Objective: The primary objective of this study is to assess the efficacy of 2 dosing regimens of BIIB021 in combination with exemestane in women whose HR+ breast cancer had progressed following treatment with a nonsteroidal AI. Primary end point(s): The primary endpoint of this study is progression‐free survival (PFS), which is defined as the time interval from the date of randomization until disease progression or death, whichever occurs first. Secondary Objective: The secondary objective of this study is to evaluate the safety and tolerability of BIIB021 in combination with exemestane in this study population. INCLUSION CRITERIA: To be eligible to participate in this study, candidates must meet the following eligibility criteria at the time of enrollment or at the timepoint specified in the individual eligibility criterion listed: 1. Ability to understand the purpose and risks of the study and provide signed and dated informed consent and authorization to use protected health information (PHI) in accordance with national and local subject privacy regulations. 2. Age =18 years at the time of informed consent or the age of consent in accordance with national regulations, whichever is higher. 3. Must have histologically or cytologically confirmed estrogen receptor‐positive or progesterone receptor‐positive, incurable, locally advanced, or metastatic breast cancer. • If available, pre‐existing formalin‐fixed and paraffin‐embedded (FFPE) tumor tissue must be submitted to Biogen Idec before study completion, but not necessarily prior to enrollment (see Study Reference Manual). <