Comparison of Glargine to Degludec Insulin Transition With or Without a Bridging Glargine Dose

Inclusion Criteria

• Patients must meet ALL inclusion criteria to be included in the study.
• Patient age is 18-75 years.
• Diagnosis of T1D of at least 1-year duration.
• Has the ability to provide informed consent before any trial-related activities.
• Treated with insulin glargine as their basal insulin in the 3 months preceding screening visit.
• Stable insulin regimen (defined as change of <20% in the total daily dose of insulin and no change to the basal insulin agent) over the 3 months preceding the screening visit.
• Patient willing to dose their basal insulin at bedtime.
• Hemoglobin A1c < 9% in the 3 months preceding screening visit.
• Able to self-administer their insulin doses.
• Able to do self-monitoring of blood glucose using a glucose meter and willing to do this at least 2 times daily for patients using a CGM that requires calibration prior to the study and 4 times daily for patients who were not using a CGM prior to the study.
• Agreeable to the use of a continuous glucose monitor (CGM) for the duration required in the study. If already using a CGM prior to the study, then agreeable to wearing the blinded study CGM concurrently during the study period.
• Will be reachable by phone and/or email to comply with study procedures.
• Will be able to comply with study procedures, per investigator's opinion.
• Patient agrees to not use correctional insulin unless BG ≥250 for the 48 hours before and after 1st dose of IDeg.

Exclusion Criteria

• Patient must not have ANY of the exclusion criteria to be included in the study.
• Patients with eGFR <30 on at least 2 measurements within 1-year of the screening visit.
• History of myocardial infarction within 6 months preceding the screening visit.
• Patients taking non-insulin medications for the glycemic management of T1D (including metformin, DPP-4 inhibitors, GLP-1 receptor agonists, SGLT-2 inhibitors, thiazolidinediones, alpha-glucosidase inhibitors, pramlintide)
• Known or suspected allergy to IDeg or one of its excipients.
• Pregnant, planning to become pregnant in the next 3 months or breastfeeding.
• Participation in a clinical trial with investigational drug within 1 month of the screening visit or at present.
• Skin condition that prevents the insertion of the CGM.
• Previously randomized and received drug in this study.
• Presence of decompensated or poorly controlled psychiatric conditions.
• Current known or suspected illicit substance use.
• Any anticipated surgery or procedure in the next 14 days.
• Patients using U-300 glargine as their basal insulin.
• Patients using insulin afrezza as their short-acting insulin.
• Use of glucocorticoid burst/pulse therapy within 14 days prior to screening visit (chronic stable glucocorticoid doses are acceptable).