Efficacy and safety of alogliptin added to metformin in Japanese patients with type 2 diabetes: a randomized, double-blind, placebo-controlled trial with an open-label, long-term extension study

Aims: To evaluate the efficacy and safety of alogliptin added to metformin versus metformin monotherapy in Japanese patients with type 2 diabetes who achieved inadequate glycaemic control on metformin (500 or 750 mg/day) + diet/exercise. Methods: In a randomized, double-blind trial, 288 patients with type 2 diabetes mellitus T2DM received either 12.5 or 25mg alogliptin once daily + metformin or placebo + metformin for 12 weeks. Thereafter, 276 patients continued on one of the two alogliptin dosages + metformin in an open-label extension for 40 weeks. The primary efficacy endpoint in the randomized, double-blind phase was the change in HbA1c from baseline (week 0) to the end of treatment (week 12). The primary endpoint during the long-term extension phase was adverse events. Results: After 12 weeks both dosages of alogliptin + metformin produced significantly greater changes from baseline in HbA1c than placebo (metformin monotherapy: with changes in LS means -0.55 and -0.64% vs. 0.22%, respectively; p<0.0001). Incidences of adverse effects were comparable between groups, with no increases in hypoglycaemia. Over 52 weeks, there were no safety or tolerability concerns with alogliptin when added to metformin. Conclusions: Alogliptin 12.5 and 25 mg once daily was safe and effective when added to metformin (500 or 750 mg/day) in Japanese patients with inadequately controlled type 2 diabetes on metformin alone.