A Study to Compare the Glycemic Effects, Safety, and Tolerability of Exenatide Once Weekly to Those of Sitagliptin and Pioglitazone,in Subjects With Type 2 Diabetes Treated With Metformin (DURATION - 2)

A Randomized, Double-Blind, Parallel-Group, Multicenter Study to Compare the Glycemic Effects, Safety, and Tolerability of Exenatide Long-Acting Release(Once Weekly) to Those of Sitagliptin and a Thiazolidinedione in Subjects With Type 2 Diabetes Mellitus Treated With Metformin

This study will compare the benefits of exenatide once weekly treatment to those achieved by the approved antidiabetic therapies sitagliptin and pioglitazone in subjects whose type 2 diabetes is managed with metformin therapy alone. The safety and tolerability of the three treatment regimens will also be compared.

Inclusion Criteria:

• Has been diagnosed with type 2 diabetes mellitus

• Has a hemoglobin-specific A1c fraction (HbA1c) of 7.1% to 11.0%, inclusive, at study start

• Has a body mass index (BMI)of 25 kg/m2 to 45 kg/m2, inclusive, at study start

• Has been on a stable treatment regimen of metformin for a minimum of 2 months prior to study start

• Either is not treated with or has been on a stable treatment regimen with any of the following medications for a minimum of 2 months prior to study start:

  1. Hormone replacement therapy (female subjects)
  2. Oral contraceptives (female subjects)
  3. Antihypertensive agents
  4. Lipid-lowering agents
  5. Thyroid replacement therapy
  6. Antidepressant agents
  7. Drugs known to affect body weight, including prescription medications (e.g. orlistat [XENICAL®], sibutramine [MERIDIA®], topiramate [TOPAMAX®]) and over-the-counter antiobesity agents

Exclusion Criteria:

• Has been previously exposed to exenatide once weekly

• Has donated blood within 60 days of study start or is planning to donate blood during the study

• Currently being treated, or is expected to require or undergo treatment with any of the following treatment-excluded medications:

  1. Exenatide (BYETTA®) or any Dipeptidyl peptidase-4 DPP-4)inhibitor, sulfonylurea (SU), thiazolidinedione (TZD), or glucagon-like peptide (GLP)-1 analog within 3 months prior to study start
  2. Alpha-glucosidase inhibitor, meglitinide, nateglinide, or pramlintide (SYMLIN®) within 30 days of study start
  3. Insulin within 2 weeks of study start or for more than 1 week within 3 months of study start
  4. 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
  5. Drugs interacting with the CYP2C8 enzyme system, including gemfibrozil (LOPID®) and rifampin

• Has received any investigational drug within 1 month (or five half-lives of investigational drug, whichever is greater) of study start

• Has previously experienced a clinically significant adverse event (e.g., significant edema) related to TZD or DPP-4 inhibitor use