Safety and Efficacy of Exenatide in Patients With Type 2 Diabetes Using Metformin or Sulfonylureas and Metformin

Inclusion Criteria: * Treated with a stable dose of one of the following for at least 3 months prior to screening: \* \>=1000 mg/day immediate-release metformin; or metformin \>=1000 mg/day and sulfonylurea; or sulfonylurea/metformin combination therapy. * HbA1c between 7.1% and 11.0%, inclusive. * Body Mass Index (BMI) \>21 kg/m\^2 and \<35 kg/m\^2. Exclusion Criteria: * Have participated in this study previously, or any other study using exenatide or GLP-1 analogs. * Have participated in an interventional, medical, surgical, or pharmaceutical study within 30 days of screening. * Have characteristics contraindicating metformin or sulfonylurea use. * Have been treated with exogenous insulin for more than 1 week within the 3 months prior to screening. * Have used drugs for weight loss within 1 month of screening.