Conditions: Type 2 Diabetes
Keywords: Incretin, DPP-4 inhibitor
Allocation: RANDOMIZED | Intervention model: CROSSOVER
Enrollment: 16
Healthy volunteers: no

Brief summary:
Objectives: To quantify differences in control of glycemia (primary objective) and the secretion of endogenous incretin hormones (secondary objective) comparing sitagliptin or placebo added to pre-existing therapy with liraglutide and metformin

Detailed description:
This is a double blind, controlled, cross-over comparison of adding sitagliptin (or placebo) to pre-existing metformin+liraglutide therapy. Patients with type 2 diabetes mellitus (T2DM) on pre-existing treatment with metformin (≥ 1500 mg/d) monotherapy or metformin plus liraglutide (1.2 mg/d) will be studied. Patients on metformin monotherapy will, after screening and randomization, enter a run-in period of 2 weeks with the additional treatment of liraglutide (0.6 mg/d for 1 week followed by 1.2 mg/d for another week). At the end of this 2 weeks therapy, a mixed meal challenge will take place, with the assessment of glucose and hormone responses (insulin, C-peptide, glucagon, GLP-1 \[glucagon-like peptide-1\], GIP (gastric inhibitory peptide) and gastric emptying as measured by 13C (carbon 13)-octanoate breath tests. Prior to the meal tests, liraglutide will be administered at a dose of 1.2 mg per injection, which is the recommended dose for treatment. Sitagliptin will be used at a dose of 100 mg, which is recommended for clinical use.

Arms:
arm 1: None arm 2: None

Interventions: intervention 1: Placebo intervention 2: Mixed meal test intervention 3: Liraglutide intervention 4: Sitagliptin
Intervention descriptions: intervention 1: Patients administered a single dose of placebo during a mixed meal challenge. intervention 2: Subjects will be instructed to consume the mixed meal test within 20 minutes. The exact start and stop time of the mixed meal test consumption will be recorded in the CRF. The mixed meal test procedures will be identical for all subjects randomised in the study. To detect the plasma glucose excursion after mixed meal test, plasma glucose will be closely monitored intervention 3: Patients on metformin monotherapy will, after screening and randomization, enter a run-in period of 2 weeks with the additional treatment of liraglutide (0.6 mg/d for 1 week followed by 1.2 mg/d for another week) that will be continued for the entire duration of the study. intervention 4: Patients administered a single dose of Sitagliptin during a mixed meal challenge.

Protocol document: