This is a single blind randomised controlled clinical trial in uncontrolled type 2 Diabetes mellitus patients on oral glucose lowering agents, and naive to incretinomimetic. Participants will be randomised in two Arms : arm 1 receiving Liraglutide at 1,2 mg/day and arm 2 Vildagliptine at 100mg/day over 14 days. The two arms will be compared for 14-day changes in insulin secretion and insulin sensitivity.

Incretinomimetics include exogenous Glucagon-Like Peptide analogs (GLP1a) such as Liraglutide, and inhibitors of Dipeptidyl peptidase IV (DPP4i) that prolong the half-life of endogenous GLP1 such as Vildagliptin. It remains unclear which of the two strategies (exogenous GLP1 or prolonging half-life of endogenous GLP1) have better short term effect on insulin sensitivity and insulin secretion in people living with type 2 diabetes.

This study aims to investigate the short-term metabolic effects of a GLP-1 analog Liraglutide versus a DPP4i Vildagliptin. It is a randomized, controlled, single-blinded clinical trial. Study population consists of uncontrolled type 2 diabetes mellitus patients (HbA1c≥7%) under mono or bi oral anti-diabetic therapy, naïve of any incretinomimetic treatment. Participants are randomized in 2 arms. The intervention in arm 1 consists of add-on subcutaneous Liraglutide at 0.6mg/day for 1 week increased to 1.2mg the second week. In the second arm, it consists of oral Vildagliptine at 100mg daily for two weeks. The primary outcome is the variation in euglycaemic hyperinsulinaemic clamp-derived insulin sensitivity before randomization and the day after intervention, secondary outcomes include 14-day changes in insulin secretion during a mixed meal tolarance test, body weight and body composition, and an indirect calorimetry measured resting energy expenditure. Changes from baseline to 14 days in serum creatinine and alanine amino transferase, C-reactive protein and lipid profile will also be recorded.

Inclusion Criteria:

• Type 2 diabetes mellitus known for at least one year
• Uncontrolled glycaemic profile with HbA1c ≥ 7% on oral antidiabetic mono or bi-therapy
• Naïve of incretinomimetic treatment
• Informed consent

Exclusion Criteria:

• Change in antidiabetic treatment less than 3 months prior to inclusion
• Pancreatitis
• Alanine amino transferase > 3 times the normal values
• Pregnant or breastfeeding women
• Estimated glomerular filtration rate < 60ml/min
• Infection less than 10 days prior to inclusion or during the study
• Acute complication of diabetes
• Total haemoglobin < 11g/dL in women or < 13g/dL in men
• Withdrawal of consent