MK0431 (Sitagliptin) and Metformin Co-Administration Factorial Study in Patients With Type 2 Diabetes Mellitus (0431-036)

MK0431 oral tablets will be started on Day 1 at 50 mg q.d. (q.d. = once daily) and increased after one week to a stable dose of 50 mg b.i.d. (b.i.d. = twice daily) Patients will continue to take MK0431 50 mg b.i.d. for the remainder of the 54-week base study (including the 24-week placebo-controlled Phase A and 30-week active-controlled Phase B) and during the 50-week extension study (for patients who complete the 54-week base study and enter the 50-week extension study) for a total treatment duration of up to 104 weeks.

MK0431 oral tablets will be started on Day 1 as two 50 mg tablets (100 mg q.d.) (q.d. = once daily) and continued at this dose throughout the 54-week base study (including the 24-week placebo-controlled Phase A and 30-week active-controlled Phase B) and the 50-week extension study (for patients who complete the 54-week base study and enter the 50-week extension study) for a total treatment duration of up to 104 weeks.

During the placebo-controlled period (Day 1 through Week 24/Phase A), metformin and MK0431 matching placebos will be dispensed as oral tablets. At the beginning of the 30-week active-controlled period (Phase B), metformin will be started as 500 mg q.d. (q.d. = once daily) and up-titrated in 500 mg weekly increments to a stable dose of 1000 mg b.i.d. Patients who complete the 54-week base study and who enter the 50-week extension study will continue to take metformin 1000 mg b.i.d. (b.i.d. = twice daily) for a total placebo/metformin treatment duration of up to 104 weeks.

Metformin oral tablets will be started on Day 1 at 500 mg q.d. (q.d. = once daily) and increased after 1 week to a stable dose of 500 mg b.i.d. (b.i.d. = twice daily) Patients will continue to take metformin 500 mg b.i.d. for the remainder of the 54-week base study (including the 24-week placebo-controlled Phase A and 30-week active-controlled Phase B) and during the 50-week extension study (for patients who complete the 54-week base study and enter the 50-week extension study) for a total treatment duration of up to 104 weeks.

MK0431 oral tablets will be started on Day 1 at 50 mg q.d. (q.d. = once daily) and increased after one week to a stable dose of 50 mg b.i.d. (b.i.d. = twice daily) Metformin oral tablets will be started on Day 1 at 500 mg q.d. and increased by increments of 500 mg per week to achieve a stable dose of 1000 mg b.i.d. The open-label treatment period is 24 weeks.

Metformin oral tablets will be started on Day 1 at 500 mg q.d. (q.d. = once daily) and increased by increments of 500 mg per week to achieve a stable dose of 1000 mg b.i.d. (b.i.d. = twice daily) Patients will continue to take metformin 1000 mg b.i.d. for the remainder of the 54-week base study (including the 24-week placebo-controlled Phase A and 30-week active-controlled Phase B) and during the 50-week extension study (for patients who complete the 54-week base study and enter the 50-week extension study) for a total treatment duration of up to 104 weeks.