A Study to Compare the Effects of Exenatide and Sitagliptin on Postprandial Glucose in Subjects With Type 2 Diabetes Mellitus

Inclusion criteria

• Treatment with metformin for at least 2 months
• Has HbA1c 7.0% to 11.0%, inclusive, at screening
• Body mass index (BMI)25 kg/m^2 to 45 kg/m^2, inclusive
• List of medications that are not allowed or the patient has been on stable treatment for at least 2 months:

• Hormone replacement therapy (female subjects)
• Oral contraceptives (female subjects)
• Antihypertensive agents
• Lipid-lowering agents
• Thyroid replacement therapy

Exclusion criteria

• Has been treated with exenatide (BYETTA®) or any DPP-4 inhibitor prior to screening
• Received any study medication or participated in any type of clinical trial within 30 days prior to screening
• Has donated blood within 60 days of screening visit or is planning to donate blood during the study
• Treated with any of the following medications:

• Sulfonylurea or Thiazolidinedione within 3 months of screening;
• Alpha-glucosidase inhibitor, meglitinide, nateglinide, or pramlintide (SYMLIN®)within 30 days of screening;
• Insulin within 2 weeks prior to screening or insulin for longer than 1 week within 6 months of screening;
• Drugs that directly affect gastrointestinal motility, including but not limited to, anticholinergics, macrolide antibiotics, dopamine antagonists, opioids, and Reglan®(metoclopramide);
• Systemic corticosteroids by oral, intravenous, or intramuscular route; or potent, inhaled, or intrapulmonary (including ADVAIR®) steroids known to have a high rate of systemic absorption;