Sitagliptin — A New Oral Agent for Diabetes

Incretins (e.g., glucagon-like peptide 1 and glucose-dependent insulinotropic peptide) are intestinal peptide hormones — secreted in response to a meal — that stimulate insulin secretion, suppress glucagon release, and delay gastric emptying. They are degraded by an enzyme called DPP-4; inhibition of this enzyme enhances their effects, which include reducing blood glucose. Sitagliptin (Januvia), a DPP-4 inhibitor that was recently FDA-approved for treatment of type 2 diabetes, was evaluated in these two randomized trials. Both were funded by the manufacturer, which employs several of the authors.

In one trial, 711 type 2 diabetic patients (HbA_1c range, 7%–10%) received monotherapy with sitagliptin or placebo. At 24 weeks, mean HbA_1c had decl…