Efficacy and tolerability of vildagliptin in drug-naïve patients with type 2 diabetes (T2DM) and mild hyperglycemia

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.

DPP-4 inhibitors as a new target of action for Type 2 diabetes mellitus: a focus on vildagliptin

The purpose of this review is to highlight the role of the incretin system and discuss the role of dipeptidyl peptidase (DPP)-4 inhibitors as potential treatment for diabetes, drawing attention to some of the available clinical trial data that support the use of such agents. The DPP-4 enzyme is involved in the breakdown of glucagon-like peptide (GLP)-1, an incretin that has a very short half-life. DPP-4 inhibitors delay the degradation of GLP-1, in turn extending the action of insulin and suppressing the release of glucagon. Endogenous and exogenous GLP-1 not only stimulates the release of insulin, but also reduces the secretion of glucagon. The latter action may be very important and represents a neglected aspect of the treatment of diabetes. The focus of the review is on one of the DPP-4 inhibitors, vildagliptin, since there is much recently published data on this drug. Vildagliptin has been shown to decrease hemoglobin A_1C by 0.5-0.8% either alone or in combination. Generally, it is found to be well tolerated and safe, at least in the short term.