AVANDAMET Versus Metformin For Type 2 Diabetes Mellitus

Inclusion Criteria: * Patients between 18 and 75 years of age with Type 2 Diabetes Mellitus and are currently on metformin monotherapy for glycemic control (100mg daily for at least 3 months prior to screening). * Patients must have stopped previous treatment with thiazolidinediones or other anti-diabetic agents at least 3 months prior to screening. * Women must be post-menopausal, surgically sterile or using acceptable contraceptive measures. Exclusion Criteria: * Prior history of hepatocellular reaction to or severe edema associated with the use of thiazolidinediones. * Have a known hypersensitivity to thiazolidinediones or biguanides. * Currently using insulin or any oral anti-diabetic agent other than metformin. * History of metabolic acidosis. * History of substance abuse. * Have active cancer other than localized squamous or basal cell carcinoma. * Chronic disease requiring treatment with corticosteroids. * Other criteria will be evaluated at the screening visit.