Efficacy and safety of nateglinide plus vildagliptin combination therapy compared with switching to vildagliptin in type 2 diabetes patients inadequately controlled with nateglinide.

Abstract

To investigate the efficacy and safety of vildagliptin, a potent dipeptidyl peptidase-4 inhibitor, as add-on to nateglinide, compared with switching to vildagliptin in Japanese type2 diabetes patients poorly controlled with nateglinide. A total of 40 patients inadequately controlled with nateglinide were randomized to the switching group (n=20, switching from nateglinide to vildagliptin) or combination group (n=20, nateglinide plus vildagliptin). A meal tolerance test was carried out at weeks 0 and 24. The mean changes in glycated hemoglobin from baseline to week 24 were -1.2±0.3% and -0.3±0.5% in patients of the combination and switching groups, respectively, and the difference between the groups was statistically significant (P<0.001). The mean changes in area under the curve of glucose from 0 to 180min (AUC0-180min) from baseline to week 24 was -361±271.3mmol·min/L in patients of the combination group compared with 141±241.9mmol·min/L in those of the switching group (P<0.001). The incidence of hypoglycemic events was low (three in the combination group), and none of the patients developed severe hypoglycemia. Although the addition of vildagliptin to nateglinide did not significantly increase insulin secretion relative to glucose elevation (ISG) after meal load (ISG0-180min: AUC0-180min insulin/AUC0-180min glucose) in comparison with that in baseline, the mean ISG0-30min 24weeks after addition of vildagliptin to nateglinide was significantly higher than that at baseline. In contrast, switching from nateglinide to vildagliptin reduced the mean ISG0-180min, relative to baseline. The combination therapy of vildagliptin and nateglinide is effective and safe in Japanese type2 diabetes, and the improved glycemic control is as a result of augmentation of nateglinide-induced early phase insulin secretion. This trial was registered with UMIN (no. ID000004010).