Vildagliptin 100 mg Once Daily vs. Placebo as add-on Therapy in Patients With Type 2 Diabetes Inadequately Controlled With Metformin

Inclusion criteria

• Male, non-fertile female or female of childbearing potential using a medically approved birth control method
• Patients who have received metformin for at least three months prior to visit 1 and have been on a stable dose for a minimum of 8 weeks prior to visit 1
• Agreement to maintain the same dose of metformin throughout the study
• Age in the range of 18-85 years inclusive.
• HbA1c in the range of 6.5 - 8.0% (inclusive) 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 and signed informed consent to participate in the study.

Exclusion criteria

• Pregnant or lactating female

A history of:

• type 1 diabetes, diabetes that is a result of pancreatic injury, or secondary forms of diabetes, e.g. Cushing's syndrome and acromegaly.
• acute metabolic diabetic complications such as ketoacidosis or hyperosmolar state (coma) within the past 6 months.

Any of the following significant laboratory abnormalities:

• ALT, AST greater than 2 times the upper limit of the normal range at visit 1.
• Direct bilirubin greater than the upper limit of the normal range at visit 1.
• Serum creatinine levels equal to or greater than 1.5 mg/dL (132 umol/L) males, equal to or greater than 1.4 mg/dL (123 umol/L) females, or a history of abnormal creatinine clearance at visit 1.
• Clinically significant TSH values outside of normal range at visit 1.
• Clinically significant laboratory abnormalities, confirmed by repeat measurement, other than hyperglycemia, hyperinsulinemia, and glycosuria at visit 1 Treatment with any oral anti-diabetic other than metformin within 3 months prior to visit 1

Other protocol-defined inclusion/exclusion criteria may apply