Efficacy and Safety of TAK-379 in Adult Subjects With Type 2 Diabetes Mellitus

Inclusion Criteria * Historical diagnosis of type 2 diabetes mellitus without the chronic use of antidiabetic therapy and an 8 week history of diet and exercise. * Historical diagnosis of type 2 diabetes mellitus on a stable dose of metformin as mono-therapy for at least 3 months prior to screening. * Glycosylated hemoglobin between 7.5% and 10.0%, inclusive. * Fasting C-peptide concentration is greater than or equal to 0.8 ng per mL. * Any other chronic medications which have been stable for at least 4 weeks prior to Screening. * Body mass index at Screening is greater than or equal to 23 kg/m2 and less than 45 kg/m2. * Able and willing to monitor his or her own blood glucose concentrations with a home glucose monitor. * Females of childbearing potential who are sexually active must agree to use adequate contraception, and can neither be pregnant nor lactating from Screening throughout the duration of the study. * Compliance with single-blinded study medication during the run-in phase is at least 75% and does not exceed 125% based on tablet counts performed by the study staff. Exclusion Criteria * Systolic blood pressure is greater than 160 mm Hg, or diastolic pressure is greater than 100 mm Hg at repeat measurements. * Any history of bladder cancer or has a history of cancer that has been in remission for less than 5 years prior to Screening (a history of basal cell carcinoma or Stage 1 squamous cell carcinoma of the skin is allowed). * Glycosylated hemoglobin is less than 7.5% and greater than 10.0%. * Creatine phosphokinase is greater than or equal to 5 times the upper limit of normal at screening. * Hemoglobin is less than or equal to 12 g per dL for males and less than or equal to 10 g per dL for females. * Alanine aminotransferase and aspartate aminotransferase are greater than or equal to 2.5 upper limit of normal. * Total bilirubin is greater than or equal to 1.5 times the upper limit of normal at screening. * Serum triglyceride concentration is greater than or equal to 400 mg per dL. * Estimated glomerular filtration rate is less than or equal to 60 mL per min using the Modification of Diet in Renal Disease equation or the Cockroft-Gault equation. * Abnormal thyroid-stimulating hormone as defined by central laboratory normals. * Positive test result for hepatitis B surface antigen or hepatitis C antibody. * Urine albumin to creatinine ratio is greater than or equal to 1000 μg per mg at screening. * History of microscopic or macroscopic hematuria. * Two consecutive unexplained positive urinalysis dip-stick and greater than or equal to 3 red blood cells per high-powered field on two consecutive measurements. * History of laser treatment for proliferative diabetic retinopathy within 6 months prior to Screening. * Diabetic gastroparesis that in the investigator's opinion is moderate or severe and hence may impair absorption of study medication. * The subject has New York Heart Association Class III or IV heart failure. * Has had coronary angioplasty, coronary stent placement, coronary bypass surgery, myocardial infarction, unstable angina pectoris, clinically significant abnormal electrocardiogram, cerebrovascular accident or transient ischemic attack within 6 months prior or at Screening. * History of any hemoglobinopathy that may affect determination of glycosylated hemoglobin. * Received treatment with probucol within 1 year of randomization. * Donated or received any blood products within 12 weeks prior to Screening. * Received treatment for greater than 7 days within 8 weeks prior to randomization or is required to take or continues taking any disallowed medication, prescription medication, herbal treatment or over-the counter medication that may interfere with evaluation of the study medication, including: * oral or systemically injected glucocorticoids * Prescription or over the counter weight-loss drugs * Peroxisome proliferator-activated receptor agonists, including fibric acid derivatives * Niacin * Ezetemibe * Bile-acid binding agents * warfarin * phenytoin * any alteration in lipid-lowering medication (change in dosage or drug) * Chronically treated with insulin. * Received any investigation drug within 4 weeks prior to Screening. * History of infection with hepatitis B, hepatitis C, or human immunodeficiency virus. * Hypersensitive to TAK-379 or its excipients. * History of drug abuse or a history of alcohol abuse within 2 years prior to Screening. * Any other physical or psychiatric disease or condition that in the judgment of the investigator may affect life expectancy or may make it difficult to successfully manage and follow the subject according to the protocol.