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

• Since no one knows which of the study options are best, participants will be "randomized" into the following study groups: Group 1 (regular dose of rosuvastatin) or Group 2 (higher dose of rosuvastatin).
• Participants will take 1 pill of rosuvastatin every day for 4 weeks. Each 4 week period is called a cycle.
• Participants will have a physical exam at baseline, on day 1 of starting rosuvastatin, and 2 month visits. Laboratory tests will be taken at baseline, on day 1 of starting rosuvastatin, 6 weeks and 2 months.

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