Safety and Efficacy Study of Alogliptin on Glycemic Control in Subjects With Type 2 Diabetes.

Inclusion Criteria: * Has type 2 diabetes mellitus and were either receiving no current treatment or currently treated with a sulfonylurea, metformin, or a combination of a sulfonylurea and metformin but experiencing inadequate glycemic control. Subjects qualified as receiving no current treatment if 1 of the following conditions applied: * Subject was newly diagnosed (ie, had not received any treatment). * Subject was treated with diet and exercise alone for the 3 months prior to Screening * Subject had received \<7 continuous days of any antidiabetic therapy within the 3 months prior to Screening. * Subject had a diagnosis of type 2 diabetes mellitus based on current American Diabetes Association criteria: fasting plasma glucose ≥126 mg/dL, oral glucose tolerance test at 2 hours after administration of the glucose load must have been ≥200 mg/dL, or symptoms of diabetes plus casual plasma glucose ≥200 mg/dL. * Body mass index ≥23 kg/m2 and ≤40 kg/m2. * Fasting C-peptide concentration ≥0.8 ng/mL. * Glycosylated hemoglobin concentration between 6.8% and 11.0%. * Fasting plasma glucose \>126 mg/dL at Screening. * No treatment within the 3 months prior to Screening with any other agents known to have effects on glucose (other than as described above, a sulfonylurea, metformin, or a combination of a sulfonylurea and metformin in subjects on antidiabetics), including but not limited to the following: * Other antidiabetic agents * Investigational antidiabetic agents * Niacin * Regular use of systemic glucocorticoids. * No treatment within the 3 months prior to Screening with weight-loss drugs * If taking other non-excluded medications, must have been on a stable dose of medication for at least 4 weeks. * Diastolic blood pressure ≤110 mm Hg and a systolic pressure of ≤180 mm Hg. * Female subjects could neither be pregnant (confirmed by laboratory testing) nor lactating, and if of childbearing potential must have been practicing adequate contraception. * Able and willing to monitor their own blood glucose concentrations with a home glucose monitor. * No major illness or debility that in the investigator's opinion prohibited the subject from completing the study. * Hemoglobin ≥12 g/dL for males and ≥10 g/dL for females. * Hepatic transaminase ≤2 x upper limit of normal. Exclusion Criteria: * History of cancer, other than squamous cell or basal cell carcinoma of the skin, that had not been in full remission for at least 1 year prior to Screening. * History of proteinuria \>1000 mg/day on a 12- or 24-hour urine collection OR a urine albumin/creatinine ratio \>1000 μg/mg at Screening. If elevated, the subject was to be rescreened within 1 week. * Serum creatinine ≥2.0 mg/dL. * History of proliferative diabetic retinopathy OR any history of laser-treated retinopathy. * History of treated peripheral or autonomic neuropathy. * History of systolic dysfunction congestive heart failure. * History of myocardial infarction within 1 year prior to Screening. * History of ulcerative colitis or Crohn's disease. * History of infection with hepatitis B, hepatitis C, or human immunodeficiency virus. * History of a psychiatric disorder that would affect the subject's ability to participate in the study. * History of anaphylactic reaction(s) to any drug. * History of angioedema. * History of alcohol or substance abuse within the last 2 years. * History of any surgery that could potentially affect the absorption of the study drug. * Receipt of any investigational drug within the preceding 30 days or a history of receipt of an investigational antidiabetic drug within the preceding 90 days.