Overview of Glucagon-Like Peptide-1 Receptor Agonists for the Treatment of Patients with Type 2 Diabetes.

BACKGROUND

It is estimated that 29.1 million people or 9.3% of the US population have diabetes, which contributes to considerable medical and financial burden. Type 2 diabetes mellitus is characterized by insulin resistance and insulin secretion impairment leading to hyperglycemia. The presence of insulin resistance is strongly correlated with obesity.

OBJECTIVE

This article reviews the available glucagon-like peptide-1 (GLP-1) receptor agonists and their role in the management of patients with diabetes, to help guide the selection of the most suitable agent for the individualized treatment of patients with type 2 diabetes.

DISCUSSION

This article reviews the evidence from phase 3 clinical trials for each of the 5 GLP-1 receptor agonists by comparing them against one another and with other existing therapies, including metformin, dipeptidyl peptidase-4 (DPP-4) inhibitors, and sulfonylureas. Incretin-based therapies have emerged as attractive agents for the treatment of type 2 diabetes. They target the GLP-1 hormone, which is partly responsible for insulin release and for attenuating hyperglycemia during meals (ie, the incretin effect). The 2 classes of incretin-based therapy currently available are GLP-1 receptor agonists and DPP-4 inhibitors, which prevent the breakdown of GLP-1. Both classes are attractive options, given their glucose-lowering effects without the adverse effects of hypoglycemia and weight gain. The different mechanisms of action of these therapies result in generally greater efficacy with GLP-1 receptor agonists, albeit at the expense of slightly increased gastrointestinal symptoms. These agents exert their effects by improving glucose-dependent insulin release, suppressing glucagon release, suppressing hepatic glucose output, and decreasing the rate of gastric emptying, thereby reducing appetite. Currently, 5 GLP-1 receptor agonists are available, including exenatide, liraglutide, albiglutide, dulaglutide, and lixisenatide; semaglutide may soon become available as the newest agent. With the exception of the investigational oral semaglutide, which has shown promising results, the other 5 agents are administered as subcutaneous injections, at different dosing intervals.

CONCLUSION

Currently, 5 GLP-1 receptor agonists are available for use in the United States. Although they are all in the same drug class, some significant differences exist among the various GLP-1 receptor agonists. The choice of a specific GLP-1 receptor agonist will depend on the patient preferences, potential adverse effects, and cost.