The Role of Basal Insulin and Glucagon-Like Peptide-1 Agonists in the Therapeutic Management of Type 2 Diabetes-A Comprehensive Review

The treatment of type 2 diabetes mellitus (T2DM) has been revolutionized by the introduction of novel therapeutic regimens following the clinical approval of the long-acting basal insulin glargine 10 years ago, followed by insulin detemir and, more recently, agents that target the glucagon-like peptide (GLP)-1 system with dipeptidyl peptidase 4 (DPP-4)-resistant products, such as liraglutide and exenatide, and DPP-4 inhibitors, such as sitagliptin, saxagliptin, alogliptin, and vildagliptin. The position and clinical efficacy of the GLP-1 mimetics are less well understood, however, and how they should be best used in the context of the established clinical efficacy of long-acting insulin analogs is yet to be defined. The aim of this review is to provide a summary of the efficacy, safety, and weight changes associated with long-acting insulin analogs (insulin glargine and insulin detemir) and two GLP-1 mimetics (exenatide and liraglutide). MEDLINE, EMBASE, and BIOSIS databases were searched with a timeframe of January 1, 2003-January 12, 2009 using the following terms: "Insulin glargine,'' with the co-indexing terms "LANTUS'' and "HOE901''; "Insulin detemir,'' with the co-indexing term "Levemir''; "Exenatide''; and "Liraglutide.'' This literature review demonstrates that GLP-1 and basal insulin therapies are effective treatment options for insulin-naive patients with suboptimal glycemic control with oral hypoglycemic agents. There are potential advantages of basal insulin and GLP-1 therapies in particular populations of patients. Further comparative data are needed to fully investigate the relative positioning of these therapies within the T2DM treatment paradigm.