Differential effects on metabolic parameters between sitagliptin and alogliptin in drug naïve subjects with type 2 diabetes

Background: Different dipeptidyl peptidase (DPP)-4 inhibitors show significant structural differences. The aim of this study was to find any differential effects on metabolic parameters between sitagliptin and alogliptin. Methods: Drug naive subjects with type 2 diabetes (T2DM) were assigned to either 25-100mg/day sitagliptin (n=37) or 6.25-25mg/day alogliptin (n=35) monotherapy. At 3 months, the levels of glycemic and non-glycemic parameters were compared with those at baseline. Results: At baseline, the levels of these parameters were similar between these two groups. At 3 months, similar glucose lowering efficacies were observed in both groups. However, distinct regulatory patters were observed with lipid profiles. In the sitagliptin group, high triglyceride (TG) and free fatty acid (FFA) levels significantly decreased. However, in the alogliptin group, significant reductions of total cholesterol (T-C), non-high density lipoprotein (non-HDL)-C and low density lipoprotein (LDL)-C levels were observed and changes of (Δ)HbA1c levels were weakly correlated with those of ΔT-C, Δnon-HDL-C or ΔLDL-C. Besides these lipid parameters, homeostasis model assessment (HOMA)-B increased in both groups (+52.3 % for sitagliptin and +91.2% for alogliptin) with significant inter-group differences (p<0.05). Both drugs are well tolerated and no clinically significant adverse events were observed. However, uric acid (UA) levels increased, although still within normal limit, in both groups. Conclusions: This study suggests that: 1) both sitagliptin and alogliptin are effective and safe as an initial therapy for T2DM. 2) alogliptin can ameliorate atherogenic lipid profiles and these atherogenic lipids may be associated with the glycemic effect during alogliptin treatment. By contrast, sitagliptin can down-regulate high TG and FFA levels. 3) although similar glucose lowering efficacies were observed, sitagliptin had a higher degree of enhancing beta-cell function than alogliptin.