Comparison Between Vildagliptin and Metformin to Sustain Reductions in HbA(1c) over 1 Year in Drug-naïve Patients with Type 2 Diabetes

Aims: To evaluate the ability of vildagliptin and metformin to sustain reductions in HbA(1c) over a 1-year treatment period in drug-naïve patients with Type 2 diabetes (Type 2 DM).

Methods: Double-blind, randomized, multicentre, active-controlled, parallel-group study of 52-week treatment with vildagliptin (100 mg daily, n = 526) or metformin (titrated to 2000 mg daily, n = 254) in drug-naïve patients (baseline HbA(1c) = 7.5-11.0%). HbA(1c) was measured periodically over 1 year.

Results: Vildagliptin and metformin each rapidly decreased HbA(1c) from an equal baseline of 8.7%. Most of the HbA(1c) reduction was attained by week 12, and the efficacy was sustained throughout 1-year treatment with both agents. At the study end, significant HbA(1c) reductions from baseline were seen with both vildagliptin (-1.0 +/- 0.1%, P < 0.001) and metformin (-1.4 +/- 0.1%, P < 0.001); however, statistical non-inferiority of 50 mg vildagliptin twice daily to 1000 mg metformin twice daily was not established. Body weight did not change during the 1-year treatment with vildagliptin (0.3 +/- 0.2 kg, P = 0.17) and decreased in metformin-treated patients (-1.9 +/- 0.3 kg, P < 0.001). The proportion of patients experiencing an adverse event was 70.1 vs. 75.4% in patients receiving vildagliptin and metformin, respectively. The proportion of patients experiencing a gastrointestinal adverse event was twofold higher in the metformin group, driven by a 3-4-fold greater incidence of diarrhoea, nausea and abdominal pain. The incidence of hypoglycaemia was similarly low in both groups (< 1%).

Conclusions: A clinically meaningful decrease in HbA(1c) that was sustained throughout a 1-year treatment in drug-naïve patients with Type 2 DM was seen with both metformin and vildagliptin monotherapy.