Type 2 diabetes mellitus is a chronic metabolic disorder characterized by progressive deterioration in the function of the pancreatic beta-cells, which are the cells that produce and secrete insulin (the hormone primarily responsible for the handling of glucose in the body). The investigators propose a randomized controlled trial to determine whether combining basal insulin with a new medication called exenatide is a therapeutic strategy that can preserve beta-cell function early in the course of type 2 diabetes.