Efficacy and safety of the dipeptidyl peptidase-4 inhibitor sitagliptin as monotherapy in patients with type 2 diabetes mellitus

The aim of this study was to assess the efficacy and safety of sitagliptin (MK-0431) as monotherapy in patients with type 2 diabetes mellitus and inadequate glycaemic control (HbA_1c ≥7% and ≤10%) on exercise and diet.

A total of 521 patients aged 27–76 years with a mean baseline HbA_1c of 8.1% were randomised in a 1:2:2 ratio to treatment with placebo, sitagliptin 100 mg once daily, or sitagliptin 200 mg once daily, for 18 weeks. The efficacy analysis was based on an all-patients-treated population using an analysis of covariance, excluding data obtained after glycaemic rescue.

After 18 weeks, HbA_1c was significantly reduced with sitagliptin 100 mg and 200 mg compared with placebo (placebo-subtracted HbA_1c reduction: −0.60% and −0.48%, respectively). Sitagliptin also significantly decreased fasting plasma glucose relative to placebo. Patients with higher baseline HbA_1c (≥9%) experienced greater placebo-subtracted HbA_1c reductions with sitagliptin (−1.20% for 100 mg and −1.04% for 200 mg) than those with HbA_1c <8% (−0.44% and −0.33%, respectively) or ≥8% to 8.9% (−0.61% and −0.39%, respectively). Homeostasis model assessment beta cell function index and fasting proinsulin:insulin ratio, markers of insulin secretion and beta cell function, were significantly improved with sitagliptin. The incidence of hypoglycaemia and gastrointestinal adverse experiences was not significantly different between sitagliptin and placebo. Sitagliptin had a neutral effect on body weight.

Sitagliptin significantly improved glycaemic control and was well tolerated in patients with type 2 diabetes mellitus who had inadequate glycaemic control on exercise and diet.