Dipeptidyl peptidase-IV (DPP-IV) inhibitors are poised to be the next major drug class for the treatment oftype 2 diabetes. Structure-activity studies of substitutions at the C5 position of the 2-cyanopyrrolidide
warhead led to the discovery of potent inhibitors of DPP-IV that lack activity against DPP8 and DPP9.Further modification led to an extremely potent (
Ki
DPP-IV = 1.0 nM) and selective (
Ki
DPP8 > 30
M;
Ki
DPP9> 30
M) clinical candidate, ABT-279, that is orally available, efficacious, and remarkably safe in preclinicalsafety studies.