Insulin Glargine in Type 1 Diabetes Mellitus

Inclusion criteria: * Subjects with type 1 diabetes mellitus for more than three years * Subjects on multiple daily injection insulin therapy, basal-bolus scheme therapy * HbA1c \<= 9 % (measured by central Lab, with DCCT aligned standard method) * Fasting C-Peptide \<= 0,1nmol/L with FBG \>126 mg/dl * Body Mass Index (BMI) \< 30 kg/m2 * Willingness to accept intensive insulin therapy * Ability and willingness to perform SMBG using plasma glucose meter * Female subjects must be postmenopausal or under adequate contraception as judged by the investigator (it may be oral contraceptives, intra-uterine device or surgical treatment) and must have a negative serum pregnancy test Exclusion criteria: * Diabetes other than type 1 diabetic mellitus * Type 1 diabetic patients with total insulin dose \>= 1 IU/kg/day * Serum creatinine \> 1.5 mg/dl, or history of renal transplantation or current renal dialysis * Congestive heart failure NYHA class II * Acute or chronic metabolic acidosis, including diabetic ketoacidosis * Clinical evidence of active liver disease, or serum ALT/AST 2 times the upper limit of the normal range * Hypoglycemia unawareness * Pregnancy or lactation * Concomitant use of β-blockers, thiazides or systemic corticosteroids * More than one episode of severe hypoglycemia with seizure or coma during the past year * Likelihood of requiring treatment during the study period with any anti-diabetic drug other than the study drugs * Failure to use adequate contraception (women of current reproductive potential only) * Known hypersensitivity to insulin glargine, or any of the excipients * Malignancy except basal cell carcinoma within the last five years * Long lasting (\> 2 weeks) treatment with systemic glucocorticoid therapy * Known adrenal insufficiency (interferes with hypoglycemia counter-regulation) * Known hemoglobinopathy or chronic anemia because it may interfere with Hb1Ac determination * History of substance or alcohol abuse within the last two years or current addiction to substances of abuse including ethanol * History of positive HIV test or Hepatitis B/C test * Any usage outside of the current SPC (Summary of the Product Characteristics) * Any clinically relevant cardiovascular, hepatic, neurologic, endocrine, or other major systemic disease other than type 1 diabetic mellitus making implementation of the protocol or interpretation of the study results difficult * History of demonstrable micro- and macro-angiopathic complications * Pre-planned surgery during the study * Blood donation of more than 500 ml during the previous 3 months for males or 6 months for females * Smoker for previous 3 months * Receipt of an experimental drug or use of an experimental device within the 30 days prior to study entry.