Randomized clinical trial of the safety and efficacy of sitagliptin and metformin co‐administered to Chinese patients with type 2 diabetes mellitus

INTRODUCTION: The results of a clinical trial to evaluate the efficacy and safety of initial combination therapy with sitagliptin and metformin in Chinese patients with type 2 diabetes and inadequate glycemic control are reported here. MATERIALS AND METHODS: This was a multicenter, randomized, double‐blind, placebo‐controlled, parallel group, 24‐week clinical trial carried out in China. Patients (n = 744) with type 2 diabetes and inadequate glycemic control (glycated hemoglobin ≥7.5 and ≤11.0%) who were either drug‐naïve or washed out of previous therapy were randomized in equal ratios to sitagliptin 100 mg once daily (q.d.; S100), metformin 500 mg twice daily (b.i.d.; M1000), metformin 850 mg b.i.d. (M1700), sitagliptin 50 mg b.i.d. plus metformin 500 mg b.i.d. (S100/M1000), sitagliptin 50 mg b.i.d. plus metformin 850 mg b.i.d. (S100/M1700), or placebo. RESULTS: The mean baseline glycated hemoglobin in randomized patients was 8.7%. Least squares mean changes from baseline in glycated hemoglobin were −0.59% (placebo), −0.99% (S100), −1.29% (M1000), −1.56% (M1700), −1.67% (S100/M1000) and −1.83% (S100/M1700) (P < 0.05 for each active group vs placebo, for S100/M1700 and S100/M1000 vs S100, and for S100/M1000 vs M1000). All treatments were generally well‐tolerated. The overall incidence of hypoglycemia (symptomatic or asymptomatic) was higher in the two co‐administration groups (S100/M1700 and S100/M1000) compared with the placebo. The incidence of symptomatic hypoglycemia was low, and similar, across all treatment groups. The incidences of gastrointestinal adverse events were generally higher in high‐dose metformin groups than in the placebo group. CONCLUSIONS: In Chinese patients with type 2 diabetes, initial combination therapy with sitagliptin and metformin was generally well‐tolerated, and provided improvement in glycemic control.