Postprandial hyperglycemia poses a challenge to closed-loop systems. Dipeptidyl peptidase-4 (DPP-4) inhibitors, like sitagliptin, reduce postprandial glucose concentrations in patients with type 2 diabetes. The objective of this study was to assess sitagliptin’s role in type 1 diabetes (T1DM) as an adjunct therapy in reducing postprandial blood glucose with an insulin-only closed-loop system.Methods:
This was a randomized, double-blinded, placebo controlled, crossover design trial. The participants were18-35 years old, had T1DM, and an HbA1c of ≤ 8.5%. A dose determination study included eight subjects with T1DM. There were three study visits. Four hours after receiving study drug (placebo, sitagliptin 50 mg, sitagliptin 100 mg), subjects underwent a mixed meal tolerance test with assessment of hormone concentrations. In a second study, 15 subjects underwent two visits receiving either placebo or 100 mg of sitagliptin plus an insulin only closed-loop system for 25 hours with timed meals. Blood glucose and other hormone concentrations were analyzed using repeated measures ANOVA.Results:
For the dose determination study, sitagliptin 100 mg resulted in reduced postprandial blood glucose (P = .006). For the closed-loop study, glucose concentrations were lower in the treatment group, most prominently during the first two study meals (P = .03). There was no difference in glucagon concentrations, but insulin concentrations and insulin delivery were lower in the treatment group.Conclusions:
Sitagliptin may be considered as an adjunct therapy in a closed-loop setting. Larger studies are needed to determine the role of oral agents like sitagliptin to lower postprandial hyperglycemia with closed loop.