This is an exploratory study to assess whether vildagliptin, an unapproved drug, can increase insulin secretion in subjects with pre-diabetes who have a defect in the insulin response and elevated levels of fasting glucose.

Inclusion Criteria:

• BMI in the range 22-45 and with a stable weight for the last 6 months
• Blood glucose criteria must be met
• Written informed consent

Exclusion Criteria:

• Pregnancy or lactation
• Previous diagnosis of type 2 diabetes or treatment with hypoglycemic agents
• Type 1 diabetes
• Evidence of cardiovascular complications as defined by the protocol
• Evidence of diabetic complications as defined by the protocol