Glycemic Holter Study (Continuous Glucose Monitoring) -

Prospective, Randomized, Open-label Study With Blinded Endpoint (PROBE Design) to Compare the 72 hr Glycemic Profiles Obtained by Continuous Subcutaneous Glucose Monitoring (CSGM) in Type 2 Diabetic Patients at Baseline With Metformin Monotherapy and After an 8-week Period With the Addition of Either Vildagliptin or Sitagliptin in Patients Insufficiently Controlled by Metformin After at Least 3 Months of Monotherapy

The study will assess glycemic variability and optimized glycemic control in T2DM patients treated with a DPP-4 inhibitor as add-on therapy to metformin.

Inclusion Criteria:

• Type 2 Diabetes Mellitus (DM) willing to perform SMBG at least 6 times daily to use the MiniMed CGMS for up to 3 consecutive days on 2 occasions.
• HbA1c: 6.5 to 9% with metformin monotherapy for a least 3 months

Exclusion Criteria:

• Age >= 80 years
• BMI <= 22 and >=40 kg/m2
• Secondary T2 DM
• Hepatic failure, ASAT/ALAT>3 ULN, and moderate/severe renal failure (CI < 50 ml/min) CHF III & IV

Other protocol-defined inclusion/exclusion criteria may apply