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.