Efficacy of add-on Therapy With Vildagliptin in Chinese Patients With Type 2 Diabetes Inadequately Controlled With Prior Metformin Monotherapy

Inclusion Criteria: * Patients with T2DM who have received metformin for at least 8 weeks and have been on a stable dose of at least 1500 mg daily for a minimum of 4 weeks prior to visit 1 * Agreement to maintain the same dose of metformin from randomization to the end of the study * Age in the range of 18-78 years inclusive * Body mass index (BMI) in the range of 20-40 kg/m2 inclusive at Visit 1 * HbA1c in the range of \> 7.0 to ≤10% at Visit 1 * Agreement to maintain prior diet and exercise habits during the full course of the study * Ability to comply with all study requirements Exclusion Criteria: * Fasting Plasma Glucose (FPG) \> 270 mg/dl (15 mmol/L) at Visit 1 * Pregnant or nursing (lactating) women Other protocol-defined inclusion/exclusion criteria may apply