Retagliptin as add-on therapy to metformin in Chinese patients with type 2 diabetes inadequately controlled with metformin: A multicentre, randomized, double-blind, placebo-controlled, phase 3 trial.

AIM:To evaluate the efficacy and safety of retagliptin in Chinese patients with type 2 diabetes (T2D) inadequately controlled with metformin. MATERIALS AND METHODS:This multicentre, phase 3 trial consisted of a 16-week, randomized, double-blind, placebo-controlled period, where patients with HbA1c levels between 7.5% and 11.0% were randomized to receive either once-daily (QD) retagliptin 100 mg (n = 87) or placebo (n = 87), both as an add-on to metformin. The primary endpoint was the change in HbA1c from baseline to week 16. RESULTS:At week 16, the least squares mean change in HbA1c from baseline, compared with placebo, was -0.82% (95% CI, -1.05% to -0.58%) for the retagliptin 100 mg QD group (P < .0001) per treatment policy estimand. Significantly higher proportions of patients in the retagliptin 100 mg QD group achieved HbA1c levels of less than 6.5% (11.5%) and less than 7.0% (26.4%) compared with those receiving placebo (0% and 4.6%; P = .0016 and P < .0001, respectively) at week 16. Retagliptin 100 mg QD also lowered fasting plasma glucose and 2-hour postprandial plasma glucose levels. The incidence of adverse events (AEs) during the treatment period was similar between the two groups. However, slightly higher proportions of increased lipase and increased amylase in the retagliptin 100 mg QD group were observed. No patients discontinued treatment permanently because of AEs, and no episodes of severe hypoglycaemia were reported. CONCLUSIONS:Retagliptin 100 mg QD as an add-on therapy to metformin offers a new therapeutic option for treating Chinese patients with T2D inadequately controlled by metformin alone, and is generally well tolerated.