Weekly Subcutaneous Semaglutide as Adjunct to Closed-loop Therapy in Type 1 Diabetes Care

Inclusion criteria

• A clinical diagnosis of T1D for at least one year, as per their treating diabetes physician in agreement with the primary investigator's clinical judgment (confirmatory C-peptide and antibodies will not be required)
• Glycated hemoglobin (HbA1c) up to 11% (inclusive), performed within the last 6 months prior to study inclusion
• Insulin pump use (of any modality) for minimum 3 months
• Agreement to the use of highly effective method of birth control in persons of child-bearing age (if sexually active) and active avoidance of pregnancy during the trial. Child-bearing potential refers to participants of the female sex post-menarche and have not reached menopause or have a disclosed medical condition causing sterility (e.g. hysterectomy). Post-menopausal state refers to the absence of menses for 12 months without any alternative cause.

Exclusion criteria

• Current or < 2 week use of another GLP1-receptor agonist
• Less than 2 weeks use of any anti-hyperglycemic agent other than insulin
• Planned or ongoing pregnancy
• Breastfeeding individuals
• Severe hypoglycemic episode within the last 3 months, defined as an event where glucose was < 4 mmol/L resulting in seizure, loss of consciousness, or need to present to the emergency department
• Severe diabetic ketoacidosis (DKA) within the last 6 months ("severe" referring to need to present to medical attention and requirement of intravenous insulin)
• Prior history of acute pancreatitis, chronic pancreatitis, or gallbladder disease
• Personal or family history of medullary thyroid cancer or multiple endocrine neoplasia type 2
• Severe impairment of renal function with eGFR <15 mL/min/1.73 m2 (using CKD-EPI formula), measured within the last 12 months
• Clinically significant diabetic retinopathy or gastroparesis, as per the clinical judgment of the investigator
• History of bariatric surgery within 6 months of screening
• Any serious medical or psychiatric illness likely to interfere with study participation as per the judgment of the investigator (e.g. cirrhosis, active cancer, decompensated schizophrenia)
• Prior adverse reaction to GLP1-RAs
• Body mass index ≤ 21 kg/m2
• Regular use of hydroxyurea during the expected time of Dexcom G6 use, as this medication is known to cause inaccurate measurements (43)
• Failure to comply to the study protocol and/or research group's recommendations (e.g. change in pump parameters, ketone measurement)
• Inability or unwillingness to comply to safe diabetes management in the view of the study group (e.g. inappropriate treatment of hypoglycemia or lack thereof)
• Any demonstrate of difficulty in using the iMAP system following training, as per investigator's judgment
• Concern for safety of the participant, as per the clinical judgment of the primary investigator

**Note that for reasons of medicolegal protection for medical supervision, participants must be Canadian residents.**