Predictive Parameters for Efficacy of Sitagliptin and Metformin Combination

It is well established that inhibition of dipeptidyl peptidase (DPP)-IV reduces glucose levels in both fasting and postprandial states and preserves pancreatic beta cell function in patients with type 2 diabetes. Their mechanism of action is derived from increased incretin (GLP-1) levels, which stimulate insulin secretion as well as insulin biosynthesis and inhibit glucagon secretion from pancreas. Recent studies reported that combination therapy with DPP-IV inhibitors and metformin have additive or synergistic effects in lowering glycose level, preserving beta-cell mass and function as well as enhancing insulin sensitivity. However, there have been few studies about the difference of glucose lowering effect of combination therapy of DPP-IV inhibitors and metformin according to the secretory capacity of pancreas.

The researchers hypothesized that combination therapy with DPP-IV inhibitor and metformin may have more favorable glucose lowering effect in type 2 diabetic patients who have preserved pancreatic secretory function. The researchers plan to investigate the difference of glucose lowering effect of 24 weeks treatment with sitagliptin (DPP-IV inhibitor) in combination with metformin according to basal c-peptide and glucagon level in type 2 diabetic patients.