Conditions: Type 2 Diabetes Mellitus
Keywords: Type 2 diabetes mellitus Dipeptidyl peptidase IV inhibitors Glucagon-like peptide 1
Allocation: NON_RANDOMIZED | Intervention model: PARALLEL
Enrollment: 24
Healthy volunteers: no

Brief summary:
The purpose of this study is to confirm the mechanism of reduced response to DPP-4 inhibitor in some patients with type 2 diabetes and evaluate appropriate patients to treat with DPP-4 inhibitor

Detailed description:
Sitagliptin, a DPP-4 inhibitor was used as an incretin enhancer in clinical practice first. In clinical trials, sitagliptin showed effective control of blood glucose level in type 2 diabetes and 100 mg once daily with metformin was similar to sulfonylurea (glipizide) with metformin in lowering HbA1c. Mostly in practice, stable blood glucose levels were maintained after change of sulfonylurea to sitagliptin in type 2 diabetes treatment. However, in some cases, there were abrupt severe hyperglycemia and uncontrolled blood glucose level after drug change to sitagliptin.

Several mechanism could be considered for reduced response to DPP-4 inhibitor in some type 2 diabetes patients. Firstly, significantly reduced secretion of glucagon-like peptide 1 (GLP-1) more than expected in diabetes or functional defect of GLP-1 activity could be the mechanism of loss of GLP-1 effect irrespective of DPP-4. Secondly, mutation or functional defect of DPP-4 enzyme could not be inhibited by DPP-4 inhibitor. Thirdly, GLP-1 receptor mutation or other defect in β-cell responsiveness to GLP-1 leads to reduction of response to DPP-4 inhibitor.

Arms:
arm 1: sitagliptin hypo-response patients arm 2: sitagliptin response patients

Interventions: intervention 1: Sitagliptin
Intervention descriptions: intervention 1: Sitagliptin (100mg, per oral) once a day.

Protocol document: