Recruiting
Phase 2
Phase 3

Tirzepatide

Sponsor:

McGill University Health Centre/Research Institute of the McGill University Health Centre

Code:

NCT07284511

Conditions

Type 1 Diabetes

Type 1 Diabetes Mellitus

T1D

T1DM

T1DM - Type 1 Diabetes Mellitus

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Interventions

Tirzepatide

Tandem Control-IQ Automated Insulin Delivery System (with Dexcom G7 CGM)

Carbohydrate Counting

No Meal Announcement

Study Details

Brief summary:

This research study is testing whether a weekly medication called tirzepatide can help adults with type 1 diabetes use their insulin pump more easily, specifically by reducing or eliminating the need to count carbohydrates at meals.

People with type 1 diabetes must take insulin for life, and even with advanced insulin pumps and continuous glucose monitors, many still struggle to keep blood sugar within the target range. One of the biggest challenges is carbohydrate counting, which requires estimating the amount of carbohydrates in every meal to give the correct insulin dose.

Tirzepatide is a medication currently approved for type 2 diabetes and weight management. Early research suggests it may also help people with type 1 diabetes by lowering appetite, slowing digestion, reducing insulin needs, and smoothing after-meal blood sugar rises.

This study will include 105 adults with type 1 diabetes at centers in Canada and Switzerland. Everyone will use the Tandem Control-IQ insulin pump with a Dexcom G7 continuous glucose monitor. Participants are randomly assigned to one of two groups:

Tirzepatide group:

Participants receive weekly tirzepatide injections. After the dose is gradually increased over 12 weeks, they will eventually try using their insulin pump without entering carbohydrate amounts at meals.

Control group:

Participants continue their usual therapy and keep counting carbohydrates for their mealtime insulin doses.

The main goal of the study is to learn whether people taking tirzepatide can safely maintain good blood sugar control without counting carbs, compared with standard care. All participants will attend several clinic visits and share their glucose, insulin, and health data throughout the 32-week trial. Some centers will also conduct heart/fitness, or body-composition tests.

As with any medication, tirzepatide may cause side effects such as nausea, vomiting, diarrhea, or decreased appetite. Rare but serious risks like gallbladder disease or pancreatitis are also monitored. Pregnancy must be avoided during the trial.

Overall, this study aims to understand whether adding tirzepatide to automated insulin delivery can simplify diabetes management, reduce burden, and maintain safe and effective glucose control for adults living with type 1 diabetes.

Conditions

Type 1 Diabetes

Type 1 Diabetes Mellitus

T1D

T1DM

T1DM - Type 1 Diabetes Mellitus

Study ID

NCT07284511

Start date

May 19, 2026

Status verified date

May, 2026

Completion date

Jan, 2029

Anticipated

Primary completion date

Jan, 2028

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Inclusion Criteria:

  • Age ≥ 18 years.
  • Clinical diagnosis of type 1 diabetes for ≥ 1 year, per investigator judgment (confirmatory C-peptide and autoantibodies not required).
  • A BMI ≥ 27 kg/m2.
  • HbA1c > 6.5%, and < 12%.
  • Current therapy: multiple daily injections or insulin pump.
  • Willingness to use Tandem Control IQ insulin pump system with the use of rapid or ultra rapid-acting insulins compatible with Tandem Control-IQ pump (e.g. Fiasp is not compatible)
  • Active carbohydrate counting for prandial insulin dosing.
  • Individuals of childbearing potential must be using or agree to use an effective birth-control method. Childbearing potential refers to participants of the female sex post-menarche who have not reached menopause and who do not have a 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:

  • Use of GLP1-RAs within the last four weeks.
  • Use of antihyperglycemic agents other than insulin or metformin within the last 2 weeks.
  • Planned or ongoing pregnancy.
  • Breastfeeding.
  • Severe hypoglycemia requiring hospitalization in the past 2 months. Severe hypoglycemia is defined as requiring the assistance of another person, due to altered consciousness, to administer carbohydrates, glucagon, or other resuscitative actions.
  • Diabetic ketoacidosis within the last 2 months.
  • History of acute or chronic pancreatitis.
  • Personal or family history of medullary thyroid cancer or multiple endocrine neoplasia type 2.
  • Severe renal impairment with eGFR <30 mL/min/1.73 m2 (CKD-EPI), measured within the last four months.
  • Clinically significant proliferative diabetic retinopathy or gastroparesis, as per the judgment of the investigator.
  • Current or ≤ 1 month use of supraphysiological doses of oral or intravenous glucocorticoids.
  • History of bariatric surgery within the last 6 months.
  • Medical or psychiatric illness likely to interfere with participation (e.g. cirrhosis, active cancer, decompensated schizophrenia), per investigator judgment.
  • Inability or unwillingness to comply with safe diabetes management practices, in the view of the investigator.
  • Any safety concern that, in the investigator's judgment, precludes participation.

Study Design

Enrollment

105 participants

Anticipated

Allocation

Randomized

Intervention Model

Parallel Assignment

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: Tirzepatide group

Participants randomized to this arm receive once-weekly subcutaneous tirzepatide in addition to use of the Tandem Control-IQ insulin pump and Dexcom G7 continuous glucose monitor. Tirzepatide is initiated at 2.5 mg weekly and increased by 2.5 mg every 4 weeks to a target dose of 10 mg weekly or the maximally tolerated dose. Dose escalation may be delayed or reduced if participants experience intolerable gastrointestinal symptoms. During Weeks 1-26, participants continue standard carbohydrate counting for all meals. Beginning in Week 27, participants stop entering carbohydrate amounts into the pump (no meal announcements) for six weeks while continuing tirzepatide at their maintenance dose. Throughout the intervention, participants undergo regular safety assessments, remote glucose data reviews, insulin-pump parameter adjustments as needed, and scheduled in-person visits to monitor metabolic, cardiovascular, and patient-reported outcomes.

active comparator: Control group

Participants randomized to the control arm use the Tandem Control-IQ automated insulin delivery system with the Dexcom G7 continuous glucose monitor, following standard-of-care diabetes management. They continue carbohydrate counting for all meals throughout the 32-week study and deliver prandial insulin boluses based on estimated carbohydrate intake, as is typical for users of hybrid closed-loop systems. No tirzepatide injections are administered. Participants receive the same device training, follow-up schedule, safety monitoring, glucose data reviews, and pump parameter adjustments as the tirzepatide arm. This arm serves as an active comparator, representing current standard therapy for type 1 diabetes with automated insulin delivery and meal announcements.

Interventions

Tirzepatide

Tirzepatide, administered as a once-weekly subcutaneous injection, initiated at 2.5 mg and escalated in 2.5-mg increments every 4 weeks to a target of 10 mg or the maximally tolerated dose, used as an adjunct therapy in adults with type 1 diabetes using the Tandem Control-IQ automated insulin delivery system.

Tandem Control-IQ Automated Insulin Delivery System (with Dexcom G7 CGM)

This intervention uses the Tandem t:slim X2 insulin pump with the Control-IQ automated insulin delivery algorithm, integrated with the Dexcom G7 continuous glucose monitor. The system adjusts basal insulin and delivers automated correction boluses based on real-time glucose values. All participants receive standardized training and use this system for the full 32-week study. Rapid-acting insulin compatible with Control-IQ is required. This intervention is distinguished by its use under two different operational strategies: standard carbohydrate counting in the control arm and complete omission of meal announcements during the final 6 weeks in the tirzepatide arm.

Carbohydrate Counting

Participants enter the estimated carbohydrate amount for every meal and snack into the Tandem Control-IQ insulin pump to calculate and deliver prandial insulin boluses. This reflects standard use of hybrid closed-loop systems. The procedure is maintained for the entire 32-week study in the control arm and during Weeks 1-26 in the tirzepatide arm.

No Meal Announcement

Participants do not enter carbohydrate amounts or announce meals to the Tandem Control-IQ system. The pump operates without user-initiated prandial boluses, relying solely on automated basal adjustments and automated correction boluses. This intervention is implemented only in the tirzepatide arm during Weeks 27-32.

Primary outcome measure

  • Daytime Time-in-Range [ Time Frame: During the final 6 weeks of the study ]

Central Contacts and Locations

Central contacts

Keddy Moise, MSc (candidate)

438-531-6896keddy.moise@mail.mcgill.ca

Rebecca Boyer-Hernandez, BSc

rebecca.boyer-hernandez@affiliate.mcgill.ca

Locations

Hygea Medical Clinic

Recruiting

Montreal, Quebec, Canada, H4A 3T2

Contacts

Keddy Moise, MSc (candidate)

438-531-6896keddy.moise@mail.mcgill.ca

Rebecca Boyer-Hernandez, BSc

rebecca.boyer-hernandez@affiliate.mcgill.ca

Principal Investigator:

Melissa-Rosina Pasqua, MD, PhD

More Information

Sponsor

McGill University Health Centre/Research Institute of the McGill University Health Centre

Last update posted

May 27, 2026

Last verified

May, 2026

Keywords

  • Type 1 Diabetes
  • Overweight or obesity in type 1 diabetes
  • Automated insulin delivery
  • Insulin pump
  • Continuous glucose monitoring
  • Tirzepatide
  • Mounjaro
  • GIP/GLP-1 receptor agonist
  • Dual incretin therapy
  • Adjunctive tirzepatide therapy
  • Tandem Control-IQ
  • Hybrid closed-loop system
  • Closed-loop insulin delivery
  • Dexcom G7

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by McGill University Health Centre/Research Institute of the McGill University Health Centre on 2026-05-27.