This study will assess the efficacy, safety and tolerability of DPP-IV Inhibitor in patients with type 2 diabetes receiving a stable dose of metformin. The anticipated time on study treatment is 3-12 months and the target sample size is 100-500 individuals.

Inclusion Criteria:

• adult patients 18-75 years of age;
• type 2 diabetes;
• stable metformin therapy for >=3 months before screening.

Exclusion Criteria:

• women who are pregnant, breast-feeding, or not using an adequate contraceptive method;
• type 1 diabetes;
• any anti-hyperglycemic medication other than metformin in the last 3 months.