Inclusion Criteria (general):

• Men and women (age 18 to 85 years)
• Participants must be nonfertile or using a medically approved birth control method. Additional information regarding this requirement available at screening
• Body mass index (BMI) ≤42 kg/m2 (inclusive)

Inclusion Criteria (for renal insufficient patients):

• Patients with mild, moderate, or severe kidney impairment. Please consult with participating physicians regarding the definitions of these levels of severity.
• Patients with diabetes must be treated with standard anti-diabetic therapy (diet and exercise, stable dose of sulfonylurea, insulin, or metiglinides) and agree to continue for the study duration

Inclusion Criteria (for healthy subjects):

• No current significant medical conditions as determined by history and physical.
• Serum creatinine with a calculated creatinine clearance (CrCl) of >80 ml/min.
• Matched to renal impaired patients in the study by age (±5 years), sex and weight (±10% BMI)
• Vital signs guided by the following ranges:

oral body temperature between 35.0-37.2 °C systolic blood pressure, 100-140 mm Hg diastolic blood pressure, 60-110 mm Hg pulse rate, 45-90 bpm

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, acute metabolic diabetic complications (eg, ketoacidosis or hyperosmolar state (coma))
• Subjects that have been enrolled in previous vildagliptin studies or other DPP
• 4 inhibitor studies within six months
• History of renal transplant or immunosuppressant therapy
• Acute infections which may affect blood glucose control or other medical condition that may interfere with the interpretation of efficacy and safety data during the study
• Any pre-existing or history of diabetic ulcer
• Any of the following within the past 6 months: myocardial infarction (MI), coronary artery bypass surgery or percutaneous coronary intervention, unstable angina or stroke
• Any of the following electrocardiogram (ECG) abnormalities: Torsades de pointes, sustained and clinically relevant ventricular tachycardia or ventricular fibrillation, second degree atrioventricular (AV) block (Mobitz 1 and 2), third degree AV block, prolonged QTc (>500 ms)
• Malignancy including leukemia and lymphoma within the last 5 years.
• Liver disease such as cirrhosis or positive hepatitis B and C.
• Any alcohol related hepatic disease.
• Patients undergoing any method of dialysis
• Use of some concomitant medications
• Significant laboratory abnormalities as specified in the protocol
• History of active substance abuse (including alcohol) within the past 2 years.
• Smokers (i.e., 10 or more cigarettes per day)
• History of hypersensitivity to any of the study drugs or to drugs with similar chemical structures

Other protocol-defined inclusion/exclusion criteria may apply