Primary Objective:

To evaluate the efficacy of switching treatment from twice-daily basal insulin to once-daily insulin glargine (U300) as part of basal bolus regime in terms of glycated hemoglobin improvement (reduction by at least 0.3%), in uncontrolled type 1 diabetes mellitus patients.

Secondary Objectives:

• To evaluate other efficacy parameters in terms of glycemic control as well as safety including hypoglycemia events, weight changes, and adverse events.
• To evaluate the effect of insulin glargine (U300) on diabetes treatment satisfaction and fear of hypoglycemia as well as patient's satisfaction regarding the number of daily injections.

The estimated average study duration is 29 weeks, including run-in period of 4 weeks; treatment period of 24 weeks, and follow-up period of 1 week.

Inclusion criteria :

• Male or Female.
• Age ≥ 18 years.
• With Type 1 diabetes mellitus.
• Being treated twice-daily with any basal insulin in combination with prandial rapid-acting insulin analogue for at least one year.
• Have an glycated hemoglobin (HbA1c) measurement of 7.5% - 10.0% at study entry.
• Patients who have signed an Informed Consent Form.

Exclusion criteria:

• Type 2 diabetes mellitus.
• Known hypoglycemia unawareness
• Repeated episodes of severe hypoglycemia or diabetes ketoacidosis within the last 12 months.
• End-stage renal failure or being on hemodialysis.
• Any clinically significant abnormality identified on physical examination, laboratory tests, or vital signs at the time of screening or baseline, or any major systemic disease resulting in short life expectancy that in the opinion of the Investigator would restrict or limit the patient's successful participation for the duration of the study.
• Known hypersensitivity / intolerance to insulin glargine or any of its excipients.
• Patients treated with glucagon like peptide agonists.
• Use of systemic glucocorticoids (excluding topical application or inhaled forms) for one week or more within 90 days prior to the time of screening.
• Pregnant or lactating women.
• Women of childbearing potential with no effective contraceptive method.
• Participation in another clinical trial.

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

Qualified researchers may request access to patient level data and related study documents including the clinical study report, study protocol with any amendments, blank case report form, statistical analysis plan, and dataset specifications. Patient level data will be anonymized and study documents will be redacted to protect the privacy of trial participants. Further details on Sanofi's data sharing criteria, eligible studies, and process for requesting access can be found at: https://vivli.org