Randomized Sitagliptin Withdrawal Study (MK-0431-845)

Sitagliptin 100 mg, oral, once daily for 30 weeks

Placebo to sitagliptin, 100 mg, oral, once daily for 30 weeks

At least 1500 mg/day, oral, twice daily for participants entering the study on immediate-release metformin + sitagliptin or a fixed dose combination (FDC).

At least 1500 mg/day, oral, once daily for participants entering the study on extended-release metformin + sitagliptin or a FDC.

Insulin glargine (LANTUS®) initiated at 10 units and titrated based on a treat-to-target algorithm to achieve fasting glucose levels of 72-100 mg/dL (4-5.6 mmol/L); administered once daily subcutaneously.