Vildagliptin add-on to Glimepiride Versus Placebo Added to Glimepiride in Type 2 Diabetes

Inclusion Criteria: 1. Confirmed diagnosis of T2DM by standard criteria 2. Patients who have received a stable dose of SU for at least 12 weeks prior to Visit 1 3. HbA1c ≥7.5% to ≤ 11.0% at Visit 1 and Visit 3 (Week -1) 4. Age: ≥18 to ≤ 80 years at Visit 1. 5. BMI ≥ 20 and ≤ 40 kg/m\^2 at visit 1. Exclusion Criteria: 1. FPG ≥ 270mg/dl (15.0 mmol/L) at Visit 1 or Visit 3 (Week -1) 2. Severe or repetitive hypoglycemia, as defined in section 3.1, during the run-in period (between Visit 2 and Visit 4) Other protocol-defined inclusion/exclusion criteria may apply