Inclusion Criteria

• Type 2 diabetes mellitus, experiencing inadequate glycemic control, and are receiving no current antidiabetic therapy. Subjects will qualify if both of the following conditions apply:

  • Subject has failed treatment with diet and exercise for at least one month prior to Screening
  • Subject has received less than 7 days of any antidiabetic therapy within the 3 months prior to Screening Diagnosis of type 2 diabetes must be based on current American Diabetes Association criteria.
• Body mass index greater than or equal to 23 kg/m2 and less than or equal to 45 kg/m2
• Fasting C-peptide concentration greater than or equal to 0.8 ng per mL (greater than or equal to 0.26 nmol per L). (If this screening criterion is not met, the subject still qualifies if C-peptide greater than or equal to1.5 ng per mL (greater than or equal to 0.50 nmol per L) after a challenge test.
• Glycosylated hemoglobin concentration between 7.0% and 10.0%, inclusive
• If regular use of other, non-excluded medications, must be on a stable dose for at least the 4 weeks prior to Screening. However, as needed use of prescription or over-the-counter medications is allowed at the discretion of the investigator.
• Systolic blood pressure less than or equal to 180 mm Hg and diastolic pressure less than or equal to 110 mm Hg
• Hemoglobin greater than or equal to 12 g per dL (greater than or equal to 120 gm per L) for males and greater than or equal to 10 g per dL (greater than or equal to 100 gm per L) for females
• Alanine aminotransferase less than or equal to 3 times the upper limit of normal
• Serum creatinine less than or equal to 2.0 mg per dL (less than or equal to 17 micromol per L)
• Thyroid-stimulating hormone level less than or equal to the upper limit of the normal range and the subject is clinically euthyroid
• Neither pregnant (confirmed by laboratory testing in females of childbearing potential) nor lactating.
• Female subjects of childbearing potential must be practicing adequate contraception. Adequate contraception must be practiced for the duration of participation in the study.
• 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 prohibits the subject from completing the study.
• Able and willing to provide written informed consent.

Exclusion Criteria

• Urine albumin to creatinine ratio of greater than1000 μg per mg (greater than 113 mg per mol) at Screening. If elevated, the subject may be rescreened within 1 week.
• 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. (A history of treated cervical intraepithelial neoplasia 1 or cervical intraepithelial neoplasia 2 is allowed).
• History of laser treatment for proliferative diabetic retinopathy within the 6 months prior to Screening.
• History of treated diabetic gastric paresis.
• New York Heart Association Class III or IV heart failure regardless of therapy. Currently treated subjects who are stable at Class I or II are candidates for the study.
• History of coronary angioplasty, coronary stent placement, coronary bypass surgery, or myocardial infarction within the 6 months prior to Screening.
• History of any hemoglobinopathy that may affect determination of glycosylated hemoglobin.
• History of infection with hepatitis B, hepatitis C, or human immunodeficiency virus.
• History of a psychiatric disorder that will affect the subject's ability to participate in the study.
• History of angioedema in association with use of angiotensin-converting enzyme inhibitors or angiotensin-II receptor inhibitors.
• History of alcohol or substance abuse within the 2 years prior to Screening.
• Receipt of any investigational drug within the 30 days prior to Screening or a history of receipt of an investigational antidiabetic drug within the 3 months prior to Screening.
• Prior treatment in an investigational study of SYR-322.

• Excluded Medications

  • Treatment with antidiabetic agents (other than study drug following enrollment in the study) is not allowed within the 3 months prior to Screening and through the completion of the end-of-treatment/early termination procedures. (Exception: if a subject has received other antidiabetic therapy for less than 7 days within the 3 months prior to Screening.)
  • Treatment with weight-loss drugs, any investigational antidiabetics, or oral or systemically injected glucocorticoids is not allowed from 3 months prior to randomization through the completion of the end-of-treatment/early termination procedures. Inhaled corticosteroids are allowed.
  • Subjects are not to take any medications, including over-the-counter products, without first consulting with the Study Doctor.