Metformin Add-on Regimen Comparison Study in Japanese Participants With Type 2 Diabetes Mellitus (MK-0431A-136)

A Phase III, Randomized, Placebo and Active-Controlled, Double-Blind Clinical Trial to Study the Efficacy and Safety of the Addition of Metformin in Japanese Patients With Type 2 Diabetes Mellitus Who Have Inadequate Glycemic Control on Diet/Exercise Therapy and Sitagliptin Monotherapy

This study will evaluate the effect of the addition of metformin once daily (q.d.) or twice daily (b.i.d.) to sitagliptin monotherapy in Japanese participants with Type 2 diabetes mellitus (T2DM) who have inadequate glycemic control with diet/exercise therapy and sitagliptin monotherapy. The primary hypotheses are that the addition of metformin 250 mg b.i.d. or metformin 500 mg q.d. is superior to the addition of placebo on the change from baseline in hemoglobin A1c (HbA1c) at 24 weeks and that the addition of metformin 500 mg q.d. is non-inferior to the addition of metformin 250 mg b.i.d. on the change from baseline in HbA1c at 24 weeks.

Inclusion Criteria:

• Type 2 Diabetes Mellitus (T2DM)
• Currently being treated with diet/exercise and on stable dose of sitagliptin for ≥ 4 weeks, on any additional oral hypoglycemic agent (AHA) in the prior 8 weeks, and HbA1c ≥ 6.0% and ≤ 9.0%; or
• Currently being treated with diet/exercise and on stable dose of sitagliptin for ≥ 10 weeks, not on any additional oral AHA in the prior 8 weeks, and HbA1c ≥ 6.5% and < 10.0%

Exclusion Criteria:

• Type 1 diabetes mellitus,
• Secondary diabetes mellitus, or
• Gestational diabetes mellitus