Rosuvastatin to Lower Circulating Tissue Factor Bearing Microparticles in Metastatic Breast Cancer

Inclusion Criteria: * Metastatic adenocarcinoma of the breast (Stage IV) * Actively receiving endocrine therapy for at least 6 weeks (with or without HER2 therapy) * Minimum age 18 years * ECOG Performance status of 0, 1 or 2 * Normal organ and marrow function as defined in the protocol Exclusion Criteria: * Participants may not be receiving any other study agents * Actively receiving chemotherapy (exclusive of hormonal or HER2 therapy ) within last 5 weeks * Any statin therapy within the last 3 weeks * Asian decent (including Filipino, Chinese, Japanese, Korean, Vietnamese or Asian-Indian origin) * Concomitant use of the following drugs: cyclosporine, fibrates, niacin, gemfibrozil, ketaconazole, spironolactone, cimetidine, warfarin, erythromycin, or protease inhibitors * Conditions predisposing to renal failure secondary to rhabdomyolysis * Recent history of heavy alcohol use as judged by the treating physician * Known to be pregnant (testing not required) or nursing * History of rhabdomyolysis on statin therapy * Known history of Hepatitis C or active hepatitis B infection (baseline testing not required) * Uncontrolled intercurrent illness including, but not limited to ongoing or active infection, hepatitis, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements