A Clinical Trial Using Tirzepatide to Help Adults With Type 1 Diabetes Automatically Control Their Blood Sugar

NCT07284511 | Not Yet Recruiting Phase 2 DMC FDA Drug FDA Device

• 1 other identifier: 2026-12143
• Study Type: interventional
• Target: 105
• Locations: 2 countries
• Sites: 3

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

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

Outcome Measures

Primary Outcomes (1)

• Daytime Time-in-Range

  The primary outcome is the percentage of daytime hours (06:00-24:00) during which participants' glucose levels, measured by the Dexcom G7 continuous glucose monitor, fall within the target range of 3.9-10.0 mmol/L.

  During the final 6 weeks of the study

Secondary Outcomes (31)

• Weight

  At enrollment, Week 8, Week 16, Week 24, and Week 32, At Week 8 and Week 16 post-study

• Height

  At enrollment, Week 8, Week 16, Week 24, and Week 32, At Week 8 and Week 16 post-study.

• Body Mass Index

  At enrollment, Week 8, Week 16, Week 24, and Week 32, At Week 8 and Week 16 post-study

• Waist circumference

  At enrollment, Week 8, Week 16, Week 24, and Week 32, At Week 8 and Week 16 post-study

• Waist-to-Hip Ratio

  At enrollment, Week 8, Week 16, Week 24, and Week 32, At Week 8 and Week 16 post-study.

Other Outcomes (3)

• Severe hypoglycemia

  From the time the participant signs informed consent until the end of study participation at Week 32, with additional safety follow-up at Week 8 and Week 16 post-study.

• Diabetic Ketoacidosis

  From the time the participant signs informed consent until the end of study participation at Week 32, with additional safety follow-up at Week 8 and Week 16 post-study.

• Gastrointestinal and related side effects

  From the time the participant signs informed consent until the end of study participation at Week 32, with additional safety follow-up at Week 8 and Week 16 post-study.

Study Arms (2)

Tirzepatide group

EXPERIMENTAL

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.

Drug: Tirzepatide; Device: Tandem Control-IQ Automated Insulin Delivery System (with Dexcom G7 CGM); Behavioral: Carbohydrate Counting; Behavioral: No Meal Announcement

Control group

ACTIVE COMPARATOR

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.

Device: Tandem Control-IQ Automated Insulin Delivery System (with Dexcom G7 CGM); Behavioral: Carbohydrate Counting

Interventions

Tirzepatide DRUG

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.

Also known as: Mounjaro

Tirzepatide group

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

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.

Also known as: Control-IQ, Dexcom G7

Control group; Tirzepatide group

Carbohydrate Counting BEHAVIORAL

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.

Also known as: Meal Announcement

Control group; Tirzepatide group

No Meal Announcement BEHAVIORAL

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.

Also known as: Omission of Carbohydrate Counting

Tirzepatide group

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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.

You may not qualify if:

• 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.

Sponsors & Collaborators

• Melissa-Rosina Pasqua: lead
• Breakthrough T1D: collaborator
• Institut de Recherches Cliniques de Montreal: collaborator
• Insel Gruppe AG, University Hospital Bern: collaborator

Study Sites (3)

Institut de Recherches Cliniques de Montréal

Montreal, Quebec, H2W 1R7, Canada

Location

McGill University Health Centre

Montreal, Quebec, H4A 3J1, Canada

Location

Insel Hospital, University Hospital Bern

Bern, 3010, Switzerland

Location

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Related Links

• Mounjaro Monograph

MeSH Terms

Conditions

Diabetes Mellitus, Type 1; Overweight

Interventions

Tirzepatide

Condition Hierarchy (Ancestors)

Diabetes Mellitus; Glucose Metabolism Disorders; Metabolic Diseases; Nutritional and Metabolic Diseases; Endocrine System Diseases; Autoimmune Diseases; Immune System Diseases; Overnutrition; Nutrition Disorders; Body Weight; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Glucagon-Like Peptide-1 Receptor; Glucagon-Like Peptide Receptors; Receptors, G-Protein-Coupled; Receptors, Cell Surface; Membrane Proteins; Proteins; Amino Acids, Peptides, and Proteins; Receptors, Gastrointestinal Hormone; Receptors, Peptide

Study Officials

• Melissa-Rosina Pasqua, MD-PhD

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

  PRINCIPAL INVESTIGATOR

• Ahmad Haidar, PhD

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

  STUDY DIRECTOR

Central Study Contacts

Keddy Moise, MD

CONTACT

438-531-6896; keddy.moise@affiliate.mcgill.ca

Carolyn Wright, Bachelor of Science

CONTACT

514-318-7298; carolyn.wright@mail.mcgill.ca

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: Principal Clinical Investigator

Model Details: This is a randomized, open-label, parallel-group clinical trial conducted at multiple centers. After a standardized run-in with the Tandem Control-IQ insulin pump and Dexcom G7 glucose sensor, adults with type 1 diabetes are randomized in balanced blocks to either adjunct tirzepatide or control. Randomization is stratified by site and baseline insulin therapy. Participants in both groups use the same automated insulin delivery system for 32 weeks. The tirzepatide group undergoes dose escalation, maintenance, and finally a no-meal-announcement phase, while the control group continues carbohydrate counting throughout. The primary analysis compares daytime (06:00-24:00) time-in-range (3.9-10.0 mmol/L) during the last four weeks using a non-inferiority framework. This design allows rigorous evaluation of whether tirzepatide enables safe omission of meal announcements while maintaining glucose control.

Study Record Dates

• First Submitted: November 19, 2025
• First Posted: December 16, 2025
• Study Start: January 5, 2026
• Primary Completion (Estimated): January 1, 2028
• Study Completion (Estimated): January 1, 2029
• Last Updated: December 16, 2025

Record last verified: 2025-11

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP, ICF, CSR, ANALYTIC CODE
• Time Frame: IPD will be made available beginning 12 months after publication of the primary results and for a period of five years thereafter.
• Access Criteria: Researchers must submit a scientifically valid proposal and sign a data use agreement.

Locations

CH (1); CA (2)