Sitagliptin and Vildagliptin: Efficacy of Therapy in Type 2 Diabetes

The clinical efficacy and tolerability of dipeptidyl peptidase-4 (DPP-4) inhibitors for the treatment of type 2 diabetes is supported by published clinical trials. Primary literature and review articles were obtained via a Pubmed search (2002-2008) using the search terms diabetes, sitagliptin, vildagliptin and DPP-4 inhibitors. Eleven sitagliptin trials were identified and reviewed along with 14 vildagliptin studies. Clinical data pertinent to this review were also included. Sitagliptin and vildagliptin belong to a new class of therapeutic agents which enhance endogenous levels of active incretin hormones by inhibiting their degradation by the enzyme DPP-4. The agents have been studied as monotherapy; as add-on therapy to metformin, a sulfonylurea, a thiazolidinedione, and insulin; and as initial-combination therapy with a thiazolidinedione. In clinical trials, treatment with DPP-4 inhibitors produced clinically significant reductions in hemoglobin A1c (A1C). In clinical trials, treatment was weight-neutral and had a rate of hypoglycemia similar to that of placebo. DPP-4 inhibitors have proven efficacy in reducing A1C levels as monotherapy or in combination with other commonly prescribed glucose-lowering agents. More recent phase III trials indicate a sustained effect on reducing blood glucose in type 2 diabetes. DPP-4 inhibitor treatment is well tolerated both as monotherapy and in combination with other agents. This review article also discusses some related patents.