Mean (±SEM) HbA1c (a) and fasting plasma glucose (b) over time for placebo (open circles), once-daily sitagliptin 100 mg (solid diamonds) and once-daily sitagliptin 200 mg (solid squares) groups. Reproduced with permission from Raz I, Hanefeld M, Xu L, et al. 2006c. Efficacy and safety of the dipeptidyl peptidase-4 inhibitor sitagliptin as monotherapy in patients with type 2 diabetes mellitus. Diabetologia, 49:2564–71. Copyright © 2006 Springer Science and Business Media.