Safety and Efficacy of Co-Administration of Sitagliptin and Metformin in China (MK-0431-121)

• Change From Baseline in 2-hour Post Meal Glucose (2-h PMG) at Week 24 [ Time Frame: Baseline and Week 24 ]
  Change from baseline in 2-h PMG at Week 24 is defined as Week 24 2-h PMG minus Week 0 2-h PMG.
• Change From Baseline in Fasting Plasma Glucose (FPG) at Week 24 [ Time Frame: Baseline and Week 24 ]
  Change from baseline in FPG at Week 24 is defined as Week 24 FPG minus Week 0 FPG.

• Change From Baseline in 2-hour Post Meal Glucose (2-h PMG) at Week 24 [ Time Frame: 24 Weeks ]
• Change From Baseline in Fasting Plasma Glucose (FPG) at Week 24 [ Time Frame: 24 Weeks ]

• Drug: Sitagliptin 50 mg
  Sitagliptin 50 mg tablet twice a day, prior to the morning and evening meal, for 24 weeks.
  Other Name: Januvia®, Tesavel®, Xelevia®, Ristaben®
• Drug: Metformin 500 mg
  Metformin 500 mg tablet twice daily, prior to the morning and evening meal, for 24 weeks.
  Other Name: Fortamet®, Glucophage®, Glucophage® XR, Glumetza®, Riomet®, Metgluco®, Glycoran®
• Drug: Sitagliptin 100 mg
  Sitagliptin 100 mg once daily for 24 weeks.
  Other Name: Januvia®, Tesavel®, Xelevia®, Ristaben®
• Drug: Placebo
  Matching placebo tablets to sitagliptin or metformin for 24 weeks.
• Drug: Metformin 850 mg
  Metformin 850 mg tablet twice daily, prior to the morning and evening meal, for 24 weeks.
  Other Name: Fortamet®, Glucophage®, Glucophage® XR, Glumetza®, Riomet®, Metgluco®, Glycoran®

• Experimental: Sitagliptin 50 mg + metformin 500 mg
  Sitagliptin 50 mg and metformin 500 mg twice a day for 24 weeks.
  Interventions:

  • Drug: Sitagliptin 50 mg
  • Drug: Metformin 500 mg
• Experimental: Sitagliptin 50 mg + metformin 850 mg
  Sitagliptin 50 mg and metformin 850 mg twice a day for 24 weeks.
  Interventions:

  • Drug: Sitagliptin 50 mg
  • Drug: Metformin 850 mg
• Active Comparator: Metformin 500 mg
  Metformin 500 mg twice daily for 24 weeks.
  Intervention: Drug: Metformin 500 mg
• Active Comparator: Metformin 850 mg
  Metformin 850 mg twice daily for 24 weeks.
  Intervention: Drug: Metformin 850 mg
• Experimental: Sitagliptin 100 mg
  Sitagliptin 100 mg once daily for 24 weeks.
  Intervention: Drug: Sitagliptin 100 mg
• Placebo Comparator: Placebo
  Matching placebo tablets for 24 weeks.
  Intervention: Drug: Placebo

Inclusion Criteria:

• has type 2 diabetes mellitus
• is male, a female who cannot have children, or a female who agrees to use birth control during the study
• is not on an antihyperglycemic agent (AHA) (hemoglobin A1c [A1C] 7.5-11.0%) or on oral single AHA (A1C 7.0-10.5%) or low-dose AHA combination therapy (A1C 7.0-10.0%)

Exclusion Criteria:

• Patient has type 1 diabetes mellitus or ketoacidosis
• Patient is taking a dipeptidyl peptidase-4 (DPP-4) inhibitor (such as sitagliptin)
• Patient is on a weight loss program not in the maintenance phase or on a weight loss medication
• Patient has a history of liver disease, heart failure, heart disease, stroke, high blood pressure, blood disorders, or cancer
• Patient is HIV positive
• Patient is pregnant