Efficacy and Safety of Alogliptin Plus Metformin in Patients With Type 2 Diabetes

Inclusion Criteria: * Has historical diagnosis of Type 2 Diabetes Mellitus. * Has been treated with diet and exercise for at least 2 months prior to Screening, and has a Glycosylated Hemoglobin concentration between 7.5% and 10.0%, inclusive at Screening. * Has received less than 7 days of any antidiabetic medication within 2 months prior to Screening. * Body mass index greater than or equal to 23 kg/m\^2 and less than or equal to 45 kg/m\^2 (except for Asian or Asian-descendant subjects for whom the range is between 20 and 35 kg/ m\^2, inclusive). * Fasting C-peptide concentration greater than or equal to 0.8 ng/mL. * Regularly using other, non-excluded, medications must be on a stable dose for at least the 4 weeks prior to Screening. * Females of childbearing potential and males who are sexually active agree to routinely use adequate contraception from Screening throughout the duration of the study. * Able and willing to monitor their own blood glucose concentrations with a home glucose monitor and complete patient diaries. Exclusion Criteria: * Hemoglobin less than 12 g/dL for males and less than 10 g/dL for females at Screening Visit. * Has a history of any hemoglobinopathy that may affect determination of Glycosylated Hemoglobin. * Has a history of laser treatment for proliferative diabetic retinopathy within the 6 months prior to Screening. * Has a history of treatment for diabetic gastric paresis, gastric banding, or gastric bypass surgery. * Has a history of diabetic ketoacidosis or hyperosmolar non-ketotic coma. * Has systolic blood pressure greater than or equal to 150 mmHg and /or diastolic pressure greater than or equal to 90 mmHg at Screening visit. * Has New York Heart Association Class III to IV heart failure. * Has a history of coronary angioplasty, coronary stent placement, coronary bypass surgery, or myocardial infarction within the 90 days prior to Screening. * Has Alanine aminotransferase greater than 3 times the upper limit of normal at Screening. * Has a history of alcohol or substance abuse with the 2 years prior to Screening. * Serum creatinine greater than or equal to 1.5 mg/dL for males and greater than or equal to 1.4 mg/dL for females. * Has history of cancer, other than squamous cell or basal cell carcinoma of the skin that has not been in full remission for at least 5 years prior to Screening. * Has a history of infection with human immunodeficiency virus, hepatitis B virus or hepatitis C virus. * Has any major illness or debility that in the investigator's opinion prohibits the subject from completing the study. * Has received any investigational drug within the 90 days prior to Screening. * Has a history of hypersensitivity or allergy to alogliptin, other DPP-4 inhibitors, metformin or related compounds. * Has used oral or systematically injected glucocorticoids or weight loss drugs prior to 2 months to screening.