Efficacy and Safety of Vildagliptin as an Add-on to Insulin with or without Metformin in Japanese Patients with Type 2 Diabetes Mellitus: A 12-week, Double-Blind, Randomized Study

INTRODUCTION To assess the efficacy and safety of vildagliptin as add-on therapy in Japanese patients with type 2 diabetes mellitus (T2DM), inadequately controlled on stable long-acting, intermediate-acting, or pre-mixed insulin, with or without concomitant metformin. METHODS In this 12-week placebo-controlled study, patients were randomized to receive either vildagliptin 50 mg twice daily (bid) or placebo treatment in a 1:1 ratio. The primary endpoint was change in glycated hemoglobin A1c (HbA1c) from baseline to 12-week endpoint. Secondary endpoints included proportion of patients achieving pre-defined HbA1c targets of ≤6.5%, <7.0%, and HbA1c <7.0% in patients with baseline HbA1c ≤8.0% and change in fasting plasma glucose (FPG) after 12 weeks of treatment. Regular monitoring was performed to record any treatment-emergent adverse events (AEs) and serious adverse events or hypoglycemic episodes. RESULTS Of the 156 patients randomized, 96.8% completed the study (vildagliptin, n = 76; placebo, n = 75). Patient demographics and clinical characteristics were comparable between the groups at baseline. Addition of vildagliptin resulted in statistically significant reductions in HbA1c after 12 weeks (-1.01 ± 0.06%), with a between-treatment difference of -0.91 ± 0.09% (p < 0.001). FPG levels reduced from baseline to 12 weeks in the vildagliptin group (-1.2 ± 0.2 mmol/L), with a between-treatment difference of -1.2 ± 0.3 mmol/L which was significant (p < 0.001). The proportion of patients achieving HbA1c targets was higher with vildagliptin treatment for all pre-defined responder rate categories. The overall incidence of AEs was comparable between groups (vildagliptin, 46.2% vs. placebo, 43.6%). The overall incidence of hypoglycemic events was low and all events were self-treatable without using drug therapy. No severe hypoglycemic events were reported. CONCLUSION Treatment with vildagliptin 50 mg bid as add-on to insulin with or without metformin resulted in statistically significant reductions in HbA1c in Japanese patients with T2DM. Overall, vildagliptin was well tolerated with a safety profile similar to that of placebo in this patient population. ClinicalTrials.gov Identifier, NCT02002221 FUNDING: Novartis Pharma K.K.