Linagliptin monotherapy provides superior glycaemic control versus placebo or voglibose with comparable safety in Japanese patients with type 2 diabetes: a randomized, placebo and active comparator-controlled, double-blind study

Aims: To evaluate the efficacy and safety of linagliptin 5 and 10 mg vs. placebo and voglibose in Japanese patients with type 2 diabetes mellitus (T2DM). Methods: This study enrolled patients with inadequately controlled T2DM who were previously treated with one or two oral antidiabetics or were drug naive. After a 2 to 4-week washout and placebo run-in, 561 patients were randomized (2 : 2 : 2 : 1) to double-blind treatment with linagliptin 5 or 10 mg qd, voglibose 0.2 mg tid or placebo. The primary endpoint was the change from baseline in haemoglobin A1c (HbA1c) with linagliptin vs. placebo after 12 weeks and vs. voglibose after 26 weeks. Results: Baseline characteristics were well balanced across treatment groups (overall mean HbA1c was 8.01%). The adjusted mean (95% confidence interval) treatment differences at week 12 were -0.87% (-1.04, -0.70; p < 0.0001) and -0.88% (-1.05, -0.71; p < 0.0001) for linagliptin 5 and 10 mg vs. placebo and at week 26 were -0.32% (-0.49, -0.15; p = 0.0003) and -0.39% (-0.56, -0.21; p < 0.0001) for linagliptin 5 and 10 mg vs. voglibose. At week 12, mean HbA1c was 7.58, 7.48 and 8.34% in patients receiving linagliptin 5 mg, linagliptin 10 mg and placebo, respectively. At week 26, mean HbA1c was 7.63% with linagliptin 5 mg, 7.50% with linagliptin 10 mg and 7.91% with voglibose. Drug-related adverse event rates were comparable across treatment groups over 12 weeks (9.4% linagliptin 5 mg, 8.8% linagliptin 10 mg and 10.0% placebo) and 26 weeks (11.3% linagliptin 5 mg, 10.6% linagliptin 10 mg and 18.5% voglibose). There were no documented cases of hypoglycaemia. Conclusions: Linagliptin showed superior glucose-lowering efficacy and comparable safety and tolerability to both placebo and voglibose in Japanese patients with T2DM.