Effect of Linagliptin on Glycemic Control in Chinese Patients with Newly-Diagnosed, Drug-Naïve Type 2 Diabetes Mellitus: A Randomized Controlled Trial

BACKGROUND This study aimed to evaluate the efficacy and safety of linagliptin (a novel dipeptidyl peptidase (DPP)-4 inhibitor) on glucose metabolism and β-cell function in Chinese patients with newly-diagnosed, drug-naïve type 2 diabetes mellitus (T2DM). MATERIAL AND METHODS Newly-diagnosed and drug-naïve T2DM patients were enrolled. After 4-week lifestyle modulation and 2-week placebo run-in, 57 patients were randomized to double-blind treatment with linagliptin (n=34) or placebo (n=23). The primary endpoint was the change from baseline in glycosylated hemoglobin A1c (HbA1c) after 24 weeks. Fasting plasma glucose (FPG), 2-h postprandial plasma glucose (2h-PPG), fasting insulin, proinsulin-to-insulin ratio, homeostasis model assessment of insulin resistance (HOMA-IR), and homeostasis model assessment of β-cell function (HOMA-β) were also evaluated. RESULTS Baseline characteristics were similar between the 2 groups. Compared with placebo, linagliptin therapy resulted in a significant decrease in HbA1C (-1.2±0.7% vs. -0.4±0.4%, P<0.001), FBG (-0.98±1.17 vs. -0.32±0.51 mmol/L, P=0.011, and 2h-PPG (-2.02±0.94 vs. -0.97±0.63 mmol/L, P<0.001). Significant differences were observed for the proinsulin/insulin ratio (P<0.001) and HOMA-β index (P=0.001). Rates of adverse events were similar between the 2 groups (30.3% vs. 27.3%). All adverse events were mild. One patient discontinued participation due to pregnancy. CONCLUSIONS Linagliptin treatment resulted in a significant and clinically meaningful improvement of glycemic control in drug-naïve Chinese patients with T2DM, as well as improved parameters of b-cell function. Linagliptin had an excellent safety profile.