Primary Objective:

- To establish initial safety/tolerability and pharmacodynamic and pharmacokinetic profiles of four formulations of SAR161271 in patients with T1DM.

Secondary Objective:

- To establish relative potency of SAR161271 compared with insulin glargine in patients with T1DM

The total per patient is between 31 and 67 days; including post-study visit between 108 and 172 days. In case of an additional late post-study visit after last dosing, approximately 213 to 279 days, broken down as follows:

• Screening: 3 to 27 days;
• Treatment Periods each 1 day with institutionalisation from Day -1 to Day 3;
• Wash-out between doses: 7 to 10 days;
• End of Study visit: 7 to 10 days after last dose.
• Post-study visit 84 to 112 days after last dosing. If necessary, additional post-study visit 6 to 7 months after last dosing.

Inclusion criteria:

• Patients who have type 1 diabetes mellitus (T1DM) as defined by American Diabetes Association average total insulin dose of <1.2 U/kg/day
• Fasting negative serum C-peptide (<0.3 nmol/L)
• Glycated hemoglobin (HbA1c) < or = 9%
• Stable insulin regimen for at least 2 months before the study
• Body weight between 50-110 kg inclusive; body mass index between 18-30 kg/m2, inclusive
• Certified as healthy for T1DM by a comprehensive clinical assessment

Exclusion criteria:

• Any history or presence of clinically relevant (for T1DM) cardiovascular, pulmonary, gastrointestinal, hepatic, renal, metabolic, hematological, neurological, psychiatric, systemic, ocular, or infectious disease, or signs of acute illness, or major diabetic complications such as diabetic retinopathy.
• Blood donation, any volume, within 1 month before inclusion.
• Presence or history of drug hypersensitivity, or allergic disease diagnosed and treated by a physician
• Regular use of any medication other than insulins in the last month before study start with the exception of thyroid hormones, metformin, lipid-lowering and antihypertensive drugs
• Positive reaction to any of the following tests: hepatitis B surface (HBs) antigen, anti-hepatitis C virus (anti-HCV) antibodies, anti-human immunodeficiency virus (HIV) 1 antibodies, anti-HIV2 antibodies.

The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.