Design and synthesis of selective DPP-4 inhibitors: Discovery of JANUVIA™ (sitagliptin), a new treatment for type 2 diabetes

ORGN 230

Ann E. Weber, Department of Medicinal Chemistry, Merck Research Laboratories, P.O. Box 2000, Mailcode RY121-105, Rahway, NJ 07065
Dipeptidyl peptidase IV (DPP-4), a member of a family of proline selective serine dipeptidases, is responsible for the N-terminal inactivation of GLP-1 and GIP, incretin hormones that evoke glucose dependent secretion of insulin and inhibition of glucagon release. Inhibitors of DPP-4 have been shown to increase circulating levels of GLP-1 and GIP, both in animal models and in the clinic, resulting in improved glucose tolerance. Thus, DPP-4 inhibitors represent a potential new therapy for type 2 diabetes. Early α-amino acid-derived DPP-4 inhibitors that were not selective over related family members, in particular DPP8 and DPP9, induced profound toxicities in preclinical species. SAR studies on two novel screening hits provided a series of β-amino acid-derived inhibitors that were highly selective over these enzymes. Optimization of this series led to the discovery of JANUVIA™ (sitagliptin), a selective DPP-4 inhibitor which was recently approved by the FDA for the treatment of type 2 diabetes.