Inclusion Criteria:  Age 20 to 65 years, ability to comply with the procedures of the study protocol. Clinical history of type 1 diabetes with onset at < 40 years of age, insulin-dependence for > 5 years at the time of enrollment. Absent stimulated C-peptide (<0,3 ng/l) in response to mixed meal test measured at 60 and 90 minutes after the start of consumption. Involvement in intensive diabetes management, defined as self-monitoring of glucose values no less that mean of three times each day averaged over each week and by the administration of three or more insulin injections each day or in-sulin pump. Management under the direction of a diabetologist with at least 3 clin¬ical evaluations during the12 months prior to study enrollment. At least on episode of severe hypoglycemia in the 12 months prior to the study enrollment Reduced awareness of hypo glycaemia (as specified in detail in the full protocol) during the screening period OR marked glycemic lability characterized by wide swings in blood glucose despite optimal diabetes therapy  Exclusion Criteria:  Body Mass Index (BMI) >30 kg/m2 or patient weight ≤50 kg. Insulin requirement of >1.0 IU/kg/day or <15 U/day. glomerular filtration rate <80 mL/min/1.73 m2 Additional exclusion criteria specified in the full protocol