Dipeptidyl Peptidase-4 Inhibitor

Recent advances in incretin biology have led to the development of a new class of oral anti-diabetic drugs. To date, there are two known incretin hormones, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), of which the former is a more important therapeutic target for type 2 diabetes. GLP-1 is secreted by intestinal L-cells in response to oral nutrient intake, and it stimulates insulin secretion and suppresses glucagon secretion in a glucose-dependent manner. However, both GLP-1 and GIP are rapidly degraded by dipeptidyl peptidase-4 (DPP-4), a multifunctional type II transmembrane glycoprotein. Thus, several DPP-4 inhibitors with different pharmacologic features are now available and can be used either as monotherapy or in combination with other anti-diabetic agents for the treatment of type 2 diabetes. In both therapeutic regimens, DPP-4 inhibitors have been shown to reduce hemoglobin A1c levels by approximately 0.5-0.8%. In clinical trials, DPP-4 inhibitors were generally well-tolerated, posed a low risk of hypoglycemia, and did not increase body weight. Despite some reports of a possible increased risk of pancreatitis with GLP-1 receptor agonists and DPP-4 inhibitors, no causal associations have been found. Recent randomized controlled clinical trials have shown that DPP-4 inhibitors did not increase or decrease the rates of major adverse cardiovascular events in patients with type 2 diabetes at high risk of cardiovascular disease, even though this class of anti-diabetic agents had various salutary effects in many studies involving animals or healthy and diabetic humans. Additional studies will be required to resolve these disparate conclusions. (Korean J Med 2014;87:1-8)