A Multicenter Randomized, Double-Blind, Placebo-Controlled Study to evaluate the efficacy, safety and tolerability of MBX-8025, a novel PPAR-d agonist to treat hyperlipidemia, insulin resistance and obesity in overweight, hyperlipidemic patients, both as monotherapy and in combination with Atorvastatin

Total participation for each patient is approximately 16-17 weeks, which may include up to a 2 week screening period, 5 week run-in period, 8 week treatment period, and 2 week follow-up. During the run-in period patients taking statins, statin combination or Zetia will undergo a 'washout'. All patients will be instructed to follow a weight-maintenance diet (i.e., their same diet prior to entering the study). They will be asked to defer initiating any weight loss diets or meaningful changes in their activity level until after they have completed the study. Once randomized into the double blind study, patients will visit the clinic every two weeks thereafter until the end of the study. At the end of the 8-week treatment phase, the double-blind study medication will be discontinued. Patients will attend a follow up visit two weeks after their final dose for safety evaluation.

Total participation for each patient is approximately 16-17 weeks, which may include up to a 2 week screening period, 5 week run-in period, 8 week treatment period, and 2 week follow-up. During the run-in period patients taking statins, statin combination or Zetia will undergo a 'washout'. All patients will be instructed to follow a weight-maintenance diet (i.e., their same diet prior to entering the study). They will be asked to defer initiating any weight loss diets or meaningful changes in their activity level until after they have completed the study. Once randomized into the double blind study, patients will visit the clinic every two weeks thereafter until the end of the study. At the end of the 8-week treatment phase, the double-blind study medication will be discontinued. Patients will attend a follow up visit two weeks after their final dose for safety evaluation.

Inclusion Criteria:

• Age: 18-75 years
• Female patients must not be pregnant or breast-feeding
• Patients must be moderately overweight
• All patients must have abnormal cholesterol levels or a history of abnormal cholesterol levels as defined by the protocol.
• Patients taking medication to lower their cholesterol must be willing, in some cases, to discontinue their medications during the study Stable weight (a history of increasing or decreasing no more than 6.6 lbs [3 kg]) for at least 2 months prior to the study;

Exclusion Criteria

• Cancer or a history of a cancer within 5 years before screening, other than some skin cancers
• Patients planning elective surgery during the study
• Patients with a history of diabetes mellitus at study onset
• History of intolerance to, or adverse effect from atorvastatin
• History of weight loss due to stomach bypass or eating disorder
• All patients may not have had a stroke, TIA, an acute myocardial infarction, angina pectoris, coronary intervention procedure (including but not limited to angioplasty, stent placement, coronary revascularization) lower extremity bypass procedure, systemic or intracoronary fibrinolytic therapy) within 5 months of screening