Exemestane and Cyclophosphamide for Metastatic Breast Cancer

Inclusion Criteria

• Patients must have histologically confirmed breast cancer that is ER positive and/or PR positive, and HER2/neu negative and have disease that is metastatic (stage IV)
• HER2/neu negative disease determined using commercially available/approved assay in local institutional or reference laboratory, according to American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) guidelines (IHC 0-1+ or 2+ with HER2/17 ratio on FISH = 18 years.
• Eastern Cooperative Oncology Group (ECOG) performance status 0, 1, or 2.
• Patients must have normal organ and marrow function as defined below:
• absolute neutrophil count >= 1,200/mcL
• platelets >= 100,000/mcL
• hemoglobin >= 9g/dl
• total bilirubin <= 2 X upper limit of normal (ULN) [unless due to Gilbert's disease]
• AST(SGOT) <= 2.5 X ULN
• ALT(SGPT) <= 2.5 X ULN
• creatinine <= 1.5 X ULN
• Patients must be able to swallow and tolerate oral medications.
• Postmenopausal status, defined as 60 years and older, being 45 years and older and having amenorrhea x 12 months or follicle stimulating hormone levels within postmenopausal range, OR having undergone a bilateral oophorectomy.
• Ability to understand and the willingness to sign a written informed consent document.

Exclusion Criteria

• Patients may not be receiving any other investigational agents.
• Prior treatment for breast cancer with a steroidal aromatase inhibitor; with the exception of patients who were started on the combination of exemestane with everolimus less than 4 weeks prior to study entry and discontinued everolimus due to poor tolerability.
• Presence of life threatening metastatic visceral disease (defined as extensive hepatic involvement or symptomatic pulmonary lymphangitic spread) or uncontrolled brain metastases.
• Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements.