The aim of the study is to prove the efficacy of the oral intake of vildagliptin in a daily dose of 100 mg in scope of the development of type 2 diabetes in women with insulin dependent gestational diabetes in their last pregnancy not longer than 9 months after birth.

In this randomized, placebo-controlled, double-blinded clinical phase II study, 140 participants aged 18 years or older and an insulin dependent gestational diabetes in their last pregnancy should be included and treated with vildagliptin or placebo over 24 months, followed by a 12 months observation period. Exclusion criteria are pregnancy and lactation as well as a clinical overt diabetes or islet autoimmunity.

The null hypothesis is that there is no significant difference of diabetes incidence (according to ADA criteria 1997) in both groups.

Primary endpoint is the clinical manifestation of diabetes, secondary endpoints include the improvement of beta cell function (evaluable by C-peptide measurement) and of insulin sensitivity by the treatment with vildagliptin.

Inclusion Criteria:

• women with insulin-dependent gestational diabetes during the last pregnancy
• < 9 months after delivery
• age 18 years or older
• contraception during intervention period (at least 24 months)

Exclusion Criteria:

• pregnancy or lactation
• GADA or IA-2A positivity
• clinical overt diabetes