Continuous glucose profiles with vildagliptin versus sitagliptin in add-on to metformin: results from the randomized Optima study

Abstract

Aim: To compare continuous glucose monitoring (CGM) profiles on vildagliptin versus sitagliptin in addition to metformin, in patients with inadequately controlled type 2 diabetes mellitus (HbA(1c) 6.5-8.0%).

Methods: A multicenter, prospective, randomised, open-label study with blinded endpoint analysis. CGM data acquired over three days--firstly on metformin alone and then 8 weeks after the addition of either vildagliptin (n=14) or sitagliptin (n=16)--were blinded and analyzed centrally.

Results: In comparable populations with a mean baseline HbA1c of 7.1%, 24-hour glucose variability--measured by mean amplitude of glucose excursions and standard deviation of mean glucose concentration--showed similar improvement on both drugs versus metformin alone. In contrast, a series of predefined parameters reflecting daily glycaemic control--mean 24-hour blood glucose concentration, and the times spent in the optimal glycaemic range (70-140 mg/dL) and above the hyperglycaemic thresholds of 140 and 180 mg/dL together with the corresponding AUC values--were significantly improved from baseline only in the vildagliptin arm. In addition, overall hyperglycaemia (AUC[24 h] > 100 mg/dL) significantly dropped from baseline on vildagliptin [-37%] but not on sitagliptin [-9%], while postprandial hyperglycaemia (AUC[0-4 h] × 3) was significantly reduced on both, and basal hyperglycaemia (overall--postprandial hyperglycaemia was reduced only on vildagliptin [-41%; P = 0.04]).

Conclusions: The addition of a DPP-4 inhibitor significantly reduced glycaemic variability with no difference between the two drugs. However, vildagliptin induced better circadian glycaemic control than sitagliptin with a significant decrease on overall hyperglycemia, mainly driven by reduction on basal hyperglycaemia.

Trial registration: ClinicalTrials.gov NCT01193296.