Single Dose Clamp Study To Compare Concentration/Time Profile And Metabolic Activity Profile Of 2 New Formulations Of Insulin Glargine With Lantus

Inclusion criteria: * Male or female subjects, between 18 and 65 years of age, inclusive, with type 1 diabetes mellitus for more than one year, as defined by the American Diabetes Association. * Total insulin dose \<1.2 U/kg/day. * Minimum usual basal insulin dose ≥0.2 U/kg/day. * Body weight between 50.0 kg and 110.0 kg, Body Mass Index between 18.5 and 30.0 kg/m2 inclusive. * Fasting negative serum C-peptide (\<0.3 nmol/L). * Glycohemoglobin (HbA1c) ≤75 mmol/mol (≤9.0%). * Stable insulin regimen for at least 2 months prior to inclusion in study. * Certified as otherwise healthy for Type 1 diabetes mellitus patient. * Women of childbearing potential with negative pregnancy test and use of a highly effective contraceptive method or women with confirmed postmenopausal status. * Having given written informed consent prior to undertaking any study-related procedure. Exclusion criteria: * More than one episode of severe hypoglycemia with seizure, coma or requiring assistance of another person during the past 6 months. * Frequent severe headaches and / or migraine, recurrent nausea and / or vomiting (more than twice a month). * Presence or history of a drug allergy or clinically significant allergic disease according to the Investigator's judgment. * Presence or history of drug or alcohol abuse (alcohol consumption \>40 grams / day). * Smoking more than 5 cigarettes or equivalent per day, unable to refrain from smoking. * Any medication (including St John's Wort) within 14 days before inclusion, or within 5 times the elimination half-life or pharmacodynamic half-life of that drug, whichever the longest and regular use of any medication in the last month before study start with the exception of insulin products, thyroid hormones, lipid-lowering and antihypertensive drugs, and, if female, with the exception of hormonal contraception or menopausal hormone replacement therapy; any vaccination within the last 28 days; any biologics (antibody or its derivatives) given within 4 months before randomization. * Known hypersensitivity to insulin glargine or excipients of the study drug. * Any history or presence of deep leg vein thrombosis or a frequent appearance of deep leg vein thrombosis in first degree relatives (parents, siblings or children). The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.