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;