Conditions: Type 1 Diabetes
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 164
Healthy volunteers: no

Brief summary:
The objective of the proposed research is to evaluate the efficacy and safety of the use of metformin in addition to standard insulin therapy in overweight and obese children and adolescents, age 12-\<20 years, with type 1 diabetes for at least 1 year. Secondary objectives are to assess the effect of metformin on C-peptide levels, a measure of how much insulin is still being produced by the beta cells of the pancreas, and on vascular dysfunction. In addition, an ancillary study is planned to assess if metformin will improve tissue-specific insulin resistance in type 1 diabetes using a hyperinsulinemic euglycemic clamp.

Detailed description:

Arms:
arm 1: Metformin 2000 mg per day arm 2: A central pharmacy will compound a placebo to match the metformin tablets.

The placebo product will contain the following components:

* Micosolle™, silica based excipient
* Silicified Micro Crystalline Cellulose, National Formulary
* Safflower Oil, United States Pharmacopeia
* K-30 Povidone Powder
* Magnesium Stearate, National Formulary (Vegetable source)
* Fumed Silica, National Formulary

Interventions: intervention 1: Metformin (glucophage) intervention 2: oral placebo
Intervention descriptions: intervention 1: The strength of each tablet will be 500 mg. Participants will build up to a daily dose over four weeks by taking one tablet per day for 7 days, one tablet twice daily for 7 days, one tablet in morning and 2 tablets at night for 7 days, and then 2 tablets in the morning and 2 tablets at night, daily throughout the remainder of the study treatment period. intervention 2: None

Protocol document: