Pharmacokinetic and pharmacodynamic interaction of vildagliptin and voglibose in Japanese patients with type 2 diabetes

Objective: To assess the extent of pharmacokinetic and pharmacodynamic interaction between vildagliptin, a potent and selective inhibitor of dipeptidyl peptidase IV (DPP-4) enzyme, and voglibose, an α-glucosidase inhibitor widely prescribed in Japan, when co-administered in Japanese patients with type 2 diabetes. Methods: In this open-label, randomized, 3-treatment, 3-period and 6-way crossover study, 24 Japanese patients with type 2 diabetes received 50 mg vildagliptin twice daily; 50 mg vildagliptin twice daily co-administered with 0.2 mg voglibose thrice daily; or 0.2 mg voglibose thrice daily for three days in each period. Plasma concentrations of vildagliptin, DPP-4, glucagon-like peptide-1 (GLP-1), glucose, insulin, and glucagon were determined from blood samples collected at steady state. Results: Exposure to vildagliptin 50 mg (area under the concentration-time curve from 0 to 12hr (AUCtau,ss) and maximum plasma concentration at steady state (Cmax,ss) was reduced by 23% and 34% respectively with co-administration of voglibose The percentage of DPP-4 inhibition by vildagliptin remained unchanged when vildagliptin was given alone, or co-administered with voglibose; maximum inhibition was 98.3 ± 1.4% (mean ± SD) for vildagliptin alone and 97.4 ± 1.1% with co-administration. Co-administration of vildagliptin and voglibose led to greater increase in the active GLP-1 plasma concentration than vildagliptin alone (geometric mean ratio 1.63 [90% CI, 1.30, 2.03], p = 0.0007). The combination of vildagliptin and voglibose also led to significantly lower plasma glucose levels (p < 0.0001). Conclusions: Vildagliptin exposure was decreased when voglibose was co-administered, although DPP-4 inhibition remained unchanged. Co-administration led to significantly better pharmacodynamic response compared with each treatment alone, including higher active GLP-1 and lower glucose levels. The results indicate that this co-administration may be beneficial in the clinical situation. Vildagliptin and voglibose treatments, alone or when co-administered, were well tolerated in Japanese patients with type 2 diabetes