Please select the eligibility criteria that correspond to the clinical trial below.
Title: Randomized, Open Label, Two Parallel Arms, Intervention Trial Comparing the Effect of DPP-IV Inhibitor Vildagliptin vs. Glibenclamide on Circulating Endothelial Progenitor Cell Number in Patients With Type 2 Diabetes in Metformin Failure
Brief Summary: The purpose of this study is to evaluate the effect of Dipeptidyl peptidase (DPP) -IV inhibitor Vildagliptin vs. Glibenclamide on circulating endothelial progenitor cells (EPCs) number in type 2 diabetes patients in metformin failure. Subjects will be followed for 12 months after randomization.


Options:
A: Inclusion Criteria:

* Age equal or above 35 years;
* Diagnosis of type 2 diabetes mellitus as defined by the American Diabetes Association , with at least one year of disease duration at the time of the screening visit;
* Blood glucose lowering treatment with Metformin alone (monotherapy) at a stable dose of at least 1.5 g/day (or maximum tolerated dose) in the 3 months prior to the screening visit;
* Insufficient metabolic control as defined by recent (last six months) HbA1c ≥ 7% in any peripheral laboratory and confirmed at the time of the screening;
* Absence of a recent clinically-relevant progression of micro- and macro-vascular complications (see exclusion criteria);
* Written informed consent to participate to the study.

Exclusion criteria:

* Age below 35 years
* Type 1 diabetes or other causes of diabetes (pancreatectomy, gestational diabetes, etc.)
* HbA1c \< 7% or ≥ 9% at the screening visit
* Treatment with any blood glucose lowering treatment other than Metformin in the six months before screening visit
* BMI \< 20 or ≥ 40 kg/m2, or current/ past history of clinically-relevant eating disorders (including -but no limited to- nervous anorexia, bulimia, binge-eating disorders, etc.)
* Significant progression of diabetic macro-angiopathy or cardiovascular disease in the six months prior to study visit
* Significant progression of diabetic micro-angiopathy in the six months prior to study visit
* Organ failure or other severe diseases limiting life expectancy;
* Beginning, in the three months before screening visit, of any kind of drug which can modify glycemic levels (beta-blockers, diuretics...), or acute disease (acute infection, urinary tract infection...) in three months before screening visit
* History of inflammatory/infective/autoimmune chronic disease
* History of unexplained pancreatitis, chronic pancreatitis, pancreatectomy, gastric surgery, inflammatory bowel disease;
* Any clinically significant abnormality identified on physical examination, laboratory tests, ECG or vital signs at screening that in the judgment of the investigator would preclude safe completion of the study;
* Uncontrolled or inadequately controlled hypertension at screening (Systolic Blood Pressure (SBP)\>190 or Diastolic Blood Pressure (DBP) \>100 mmHg)
* Ongoing pregnancy or absence of effective contraception in women with childbearing potential
* Contraindications to the maintenance of the background therapy (Metformin), including -but not limited to- chronic kidney failure or plasma creatinine concentrations \> 1.5 mg/dL, severe respiratory failure, etc.;
* Contraindications to the use of a Sulfonylurea;
* Contraindications to the use of a DPP-IV Inhibitor;
* Laboratory findings, or other disease conditions, at the screening visit that might interfere with study measurements:

  1. Hemoglobinopathy known to affect HbA1c assays;
  2. Known chronic liver diseases, including HBV (hepatitis B virus) and HCV (hepatitis C virus) infection;
  3. Liver makers (aspartate transaminase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), Gamma-glutamyltransferase (GGT) , bilirubin) above 2 times the upper normal limit;
  4. Amylase and/or lipase above 2 times the upper normal limit;
* Chronic use of systemic and/or inhaled corticosteroids (only topical corticosteroids are allowed);
* History of low compliance, clinically-relevant psychiatric disorders or any current/ historical finding suggesting the patient as inappropriate to follow the study procedures.
B: Inclusion Criteria:

* Type 2 diabetes
* TTreatment with diet/exercise or with not more than half maximal dose of oral anti-diabetic drugs alone for at least 2 months
* Diet/exercise treated subjects with HbA1c between 7.0% and 11%, inclusive
* OAD (oral anti-diabetic drug) treated subjects with HbA1c between 7.0% and 10%, inclusive
* Body Mass Index (BMI) less than or equal to 45 kg/m\^2

Exclusion Criteria:

* Treatment with insulin for the last 3 months, except short-term treatment for intercurrent illness
* Treatment with any drug that could interfere with the glucose level (besides use of a single anti-diabetic compound)
* Any serious medical condition
C: Inclusion Criteria: Main Inclusion Criteria:

1. Is male or female and ≥18 and \<75 years old at time of informed consent.
2. Has a HbA1c of ≥7.5% and ≤10.5% based on central laboratory results from Visit 1, with individual need for therapy escalation.
3. Currently treated with a stable maximum tolarated dose (MTD) (≥1500 mg/day) of metformin therapy for at least 8 weeks prior to Enrolment visit.
4. Has a BMI of ≤45 kg/m2 at Enrolment visit.
5. Has a C-peptide laboratory value of ≥1.0 ng/mL (0.33 nmol/L; 333.3 pmol/L) based on central laboratory results from Visit 1.

Main, Exclusion Criteria:

1. Clinically diagnosed with Type I diabetes, known diagnosis of maturity onset diabetes of the young (MODY), or secondary diabetes mellitus or known presence of glutamate decarboxylase 65 (GAD65) antibodies.
2. Patients who, in the judgment of the Investigator, may be at risk for dehydration or volume depletion that may affect the patient's safety and/or the interpretation of efficacy or safety data.
3. Clinically significant cardiovascular disease or procedure within 3 months prior to Enrolment or expected to require coronary revascularization procedure during the course of the study.
4. Concomitant treatment with loop diuretics
D: Inclusion Criteria:

* Subject with Type 2 diabetes receiving treatment with at least 1,500 mg but not greater than 3000 mg of stable metformin therapy for at least 6 weeks prior to screening
* HbA1c \>or = 7% and \< or = 10%
* Fasting c-peptide \> or = 1.0 umol
* Body Mass Index \< or = 41 kg/m2
* Mean serum triglycerides \< or = 600 mg/dl

Answer: A