Dose-Ranging Study Evaluating AVE2268 in Patients With Type 2 Diabetes Not Adequately Controlled by a Metformin Treatment

Inclusion Criteria: * Type 2 diabetes mellitus, as defined by the American Diabetes Association, for at least one year at the time of screening. * HbA1c measured at visit 1 in the range of ≥ 7.0 and \< 9.0 %. * Stable metformin treatment (dose ≥ 1.5g/day for at least 3 months prior to enrollment in the study). No other antidiabetic medications are permitted for 3 months prior to enrollment. Exclusion Criteria: * Pregnant or breast-feeding women. * Women of childbearing potential not protected by medically approved contraceptive method of birth control. * BMI \>40kg/m2 * Diabetes other than type 2 diabetes. * Subjects with "brittle-diabetes" or any hospitalization or emergency room visit due to poor diabetic control within the past 6 months, previous history of diabetes related dehydration leading to hospitalization, history or evidence of ketoacidosis. * Presence or history of cancer within the past five years. * Evidence within the past 6 months of myocardial infarction, stroke, retinopathy requiring laser surgery, or heart failure requiring hospitalization. * Impaired hepatic tests, impaired renal function. * History or evidence of clinically relevant renal or urological disorder. * The investigator will evaluate whether there are other reasons why a patient may not participate.