Efficacy and Safety of Vildagliptin as add-on Therapy to Metformin in Patients With Type 2 Diabetes

Change from baseline in HbA1c at 12 weeks within subgroups of metformin doses

HbA1c will be performed on a blood sample obtained by study personnel and measured by high-performance liquid chromatography (HPLC) performed at a central laboratory.

Time frame: Baseline to 12 weeks

Change from baseline in Fasting plasma glucose (FPG) at 12 weeks

FPG will be performed on a blood sample obtained by study personnel and analyzed at a central laboratory.

Time frame: Baseline to 12 weeks

Percentage of patients meeting Responder rates in HbA1c

Responder rates will be categorized by predefined HbA1c value at 12 weeks : * Endpoint HbA1c ≤ 6.5% * Endpoint HbA1c ≤ 7% * Endpoint HbA1c ≤ 7% in patients with baseline HbA1c ≤ 8%

Time frame: 12 weeks

Number of patients with adverse events (including hypoglycemia), serious adverse events and death

The occurrence of adverse events will be sought by non-directive questioning of the patient at each visit. Adverse events are defined as appearance or worsening of any undesirable symptom, sign (including an abnormal laboratory finding), or medical conditions. Serious adverse events are any untoward medical occurrences that result in death, are life threatening, require (or prolong) hospitalization, cause persistent or significant disability/incapacity, result in congenital anomalies or birth defects, or are other conditions which in judgment of investigators represent significant hazards.