DPP4 and diabetes mellitus: Defronzo Defronzo RA RA Fleck Fleck PR PR Wilson Wilson CA CA Mekki Mekki Q Q Efficacy and safety of the dipeptidyl peptidase-4 inhibitor alogliptin in patients with type 2 diabetes and inadequate glycemic control: a randomized, double-blind, placebo-controlled study Efficacy and safety of the dipeptidyl peptidase-4 inhibitor alogliptin in patients with type 2 diabetes and inadequate glycemic control: a randomized, double-blind, placebo-controlled study Diabetes Care Diabetes Care 2008 2008 10.2337/dc08-1035 10.2337/dc08-1035 supplied-pmid 19017778?