Hormone Receptor Positive Metastatic Breast Cancer (HR+ mBC) BIIB021 Plus Aromasin Schedule Finding

Inclusion Criteria

• •Age 18 years of age
• •Must have histologically or cytologically confirmed estrogen receptor- positive or progesterone receptor-positive, incurable, locally advanced, or metastatic breast cancer.
• •Must have disease progression during treatment with a nonsteroidal AI for locally advanced or metastatic disease, or relapse during treatment or within 12 months of discontinuation of treatment in the adjuvant setting.
• •Must be a postmenopausal female.
• •Must have measurable or evaluable disease.
• •* Measurable disease is defined as \>=1 lesion with a diameter of \>=10 mm
• •* Evaluable disease is defined as bone lesions evaluable by plain X ray, CT scan, or MRI. Lesions identified only by radionuclide bone scan are not allowed.
• •One prior chemotherapy regimen for advanced mBC is allowed.
• •Prior radiotherapy is allowed.
• •Must be able to swallow and retain oral medication.
• •ECOG performance status of \<=2
• •Required laboratory values
• •* Plasma cortisol and adrenocorticotropic hormone (ACTH) levels that are not suggestive of adrenal insufficiency unless on replacement therapy for known adrenal insufficiency.