Effects of the dipeptidyl peptidase-IV inhibitor vildagliptin on incretin hormones, islet function, and postprandial glycemia in subjects with impaired glucose tolerance.

OBJECTIVE: This study was conducted to determine the effects of vildagliptin on incretin hormone levels, islet function, and postprandial glucose control in subjects with impaired glucose tolerance (IGT). RESEARCH DESIGN AND METHODS: A 12-week, double-blind, randomized, parallel-group study comparing vildagliptin (50 mg q.d.) and placebo was conducted in 179 subjects with IGT (2-h glucose 9.1 mmol/l, A1C 5.9%). Plasma levels of intact glucagon-like peptide 1 (GLP-1) and gastric inhibitory polypeptide (GIP), glucose, insulin, C-peptide, and glucagon were measured during standard meal tests performed at baseline and at week 12. Insulin secretory rate (ISR) was estimated by C-peptide deconvolution. The between-group differences (vildagliptin - placebo) in the adjusted mean changes from baseline to end point in the total and incremental (Delta) area under the curve (AUC)(0-2 h) for these analytes were assessed by ANCOVA; glucose AUC(0-2 h) was the primary outcome variable. RESULTS: Relative to placebo, vildagliptin increased GLP-1 (DeltaAUC, +6.0 +/- 1.2 pmol x l(-1) x h(-1), P < 0.001) and GIP (DeltaAUC, +46.8 +/- 5.4 pmol . l(-1) x h(-1), P < 0.001) and decreased glucagon (DeltaAUC, -3.0 +/- 1.0 pmol x l(-1) x h(-1), P = 0.003). Although postprandial insulin levels were unaffected (DeltaAUC, +20.8 +/- 35.7 pmol x l(-1) x h(-1), P = 0.561), prandial glucose excursions were reduced (DeltaAUC, -1.0 +/- 0.3 mmol x l(-1) x h(-1), P < 0.001), representing an approximately 30% decrease relative to placebo. Beta-cell function as assessed by the ISR AUC(0-2 h)/glucose AUC(0-2 h) was significantly increased (+6.4 +/- 2.0 pmol x min(-1) x m(-2) x mmol x l(-1), P = 0.002). Adverse event profiles were similar in the two treatment groups, and no hypoglycemia was reported. CONCLUSIONS: The known effects of vildagliptin on incretin levels and islet function in type 2 diabetes were reproduced in subjects with IGT, with a 32% reduction in postprandial glucose excursions and no evidence of hypoglycemia or weight gain.

Effects of vildagliptin on glucose control over 24 weeks in patients with type 2 diabetes inadequately controlled with metformin.

OBJECTIVE: We sought to evaluate the efficacy and safety of vildagliptin, a new dipeptidyl peptidase-4 inhibitor, added to metformin during 24 weeks of treatment in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: This was a double-blind, randomized, multicenter, parallel group study of a 24-week treatment with 50 mg vildagliptin daily (n = 177), 100 mg vildagliptin daily (n = 185), or placebo (n = 182) in patients continuing a stable metformin dose regimen (> or =1,500 mg/day) but achieving inadequate glycemic control (A1C 7.5-11%). RESULTS: The between-treatment difference (vildagliptin-placebo) in adjusted mean change (AMDelta) +/- SE in A1C from baseline to end point was -0.7 +/- 0.1% (P < 0.001) and -1.1 +/- 0.1% (P < 0.001) in patients receiving 50 or 100 mg vildagliptin daily, respectively. The between-treatment difference in the AMDelta fasting plasma glucose (FPG) was -0.8 +/- 0.3 mmol/l (P = 0.003) and -1.7 +/- 0.3 mmol/l (P < 0.001) in patients receiving 50 or 100 mg vildagliptin daily, respectively. Adverse events (AEs) were reported by 63.3, 65.0, and 63.5% of patients receiving 50 mg vildagliptin daily, 100 mg vildagliptin daily, or placebo, respectively. Gastrointestinal AEs were reported by 9.6 (P = 0.022 vs. placebo), 14.8, and 18.2% of patients receiving 50 mg vildagliptin daily, 100 mg vildagliptin daily, or placebo, respectively. One patient in each treatment group experienced one mild hypoglycemic event. CONCLUSIONS: Vildagliptin is well tolerated and produces clinically meaningful, dose-related decreases in A1C and FPG as add-on therapy in patients with type 2 diabetes inadequately controlled by metformin.