Efficacy and Safety of DPP-4 Inhibitors as Add-On Therapy in T2DM Patients on Dual Therapy

A randomized study assessed the efficacy and safety of three DPP-4 inhibitors vildagliptin, sitagliptin, and linagliptin as add-on therapy in 535 Chinese patients with type 2 diabetes mellitus inadequately controlled on insulin plus a traditional oral hypoglycemic agent. Over 12 weeks, all three drugs significantly improved glycemic control, reducing HbA1c as well as fasting and postprandial glucose levels. 
Vildagliptin achieved the greatest reduction in HbA1c, with the highest proportion of patients reaching target HbA1c (66.3%) and the lowest insulin requirement at weeks 6 and 12. 
Sitagliptin and linagliptin also showed improvements, though to a lesser degree. 
All treatments were well tolerated, with only mild adverse events reported. These findings suggest that while all three DPP-4 inhibitors are effective and safe as add-on therapy, vildagliptin may offer superior benefits in glycemic control and insulin dose reduction.