Conditions: Diabetes
Keywords: Diabetes
Allocation: RANDOMIZED | Intervention model: CROSSOVER
Enrollment: 16
Healthy volunteers: yes

Brief summary:
In patients with type 2 diabetes with inadequate glycemic control on diet and exercise after 6 weeks of treatment:

Objective: To assess the effects of co-administration of sitagliptin and metformin compared to placebo on hepatic glucose production (HGP).

Hypothesis: After 6 weeks of treatment, the co-administration of sitagliptin and metformin provides greater reduction in hepatic glucose production (HGP) compared to placebo.

Detailed description:
PRIMARY:

In patients with type 2 diabetes with inadequate glycemic control on diet and exercise after 6 weeks of treatment:

Objective: To assess the effects of co-administration of sitagliptin and metformin compared to placebo on hepatic glucose production (HGP).

Hypothesis: After 6 weeks of treatment, the co-administration of sitagliptin and metformin provides greater reduction in hepatic glucose production (HGP) compared to placebo.

SECONDARY:

In patients with type 2 diabetes with inadequate glycemic control on diet and exercise after 6 weeks of treatment:

1. Objective: To assess the effects of co-administration of sitagliptin and metformin compared to placebo on post-meal glucose during meal tolerance test (MTT).

   Hypothesis: After 6 weeks of treatment the co-administration of sitagliptin and metformin provides greater reduction in the total glucose AUC (0-6 hr) during MTT compared to placebo.
2. Objective: To assess the effects of co-administration of sitagliptin and metformin compared to placebo on fasting plasma glucose (FPG).

   Hypothesis: After 6 weeks of treatment the co-administration of sitagliptin and metformin provides greater reduction in FPG compared to placebo.
3. Objective: To assess the effects sitagliptin alone compared to placebo on HGP. Hypothesis: After 6 weeks of treatment, sitagliptin alone provides greater reduction in HGP compared to placebo

EXPLORATORY OBJECTIVES:

(i) Objective: after 6 weeks of treatment, to assess the effects co-administration of sitagliptin and metformin compared to placebo on:

1. active and inactive incretin concentrations (fasting and post-meal GLP-1 and fasting and post-meal GIP).
2. glucagon concentration (fasting and post-meal).
3. parameters of insulin secretion and insulin sensitivity.
4. splanchnic glucose uptake.

   (ii) Objective: after 6 weeks of treatment, to assess the effects co-administration of sitagliptin and metformin compared to treatment with sitagliptin alone and metformin alone on:
5. glucose concentration (fasting and total glucose AUC \[0-6 hr\]).
6. active and inactive incretin concentrations (fasting and post-meal GLP-1 and fasting and post-meal GIP).
7. glucagon concentration (fasting and post-meal).
8. parameters of insulin secretion and insulin sensitivity.
9. HGP.
10. splanchnic glucose uptake. (iii) Objective: after 6 weeks of treatment, to assess the effects of sitagliptin alone and metformin alone compared to placebo on:
11. glucose concentration (fasting and total glucose AUC \[0-6 hr\]).
12. active and inactive incretin concentrations (fasting and post-meal GLP-1 and fasting and post-meal GIP).
13. glucagon concentration (fasting and post-meal).
14. parameters of insulin secretion and insulin sensitivity.
15. HGP.
16. splanchnic glucose uptake.

Arms:
arm 1: Placebo to be provided for 6 weeks arm 2: Sitagliptin to be provided for 6 weeks arm 3: Metformin to be provided for 6 weeks arm 4: Sitagliptin + Metformin combined will be provided for 6 weeks

Interventions: intervention 1: Sitagliptin intervention 2: Metformin intervention 3: Sitagliptin + Metformin intervention 4: Placebo
Intervention descriptions: intervention 1: tablet, 100 mg/day, 6 weeks intervention 2: tablet, 1000 mg/ bid, 6 weeks intervention 3: tablet, Sitagliptin (100mg/day) + tablet, Metformin (1000 mg/bid), 6 weeks intervention 4: Placebo 6 weeks

Protocol document: