Adding the GIP/GLP-1 drug tirzepatide to automated insulin delivery for adults with type 1 diabetes

GIP/GLP-1RA as Adjunctive to Automated Insulin Delivery in Adults With Type 1 Diabetes: A Prospective, Randomized, Clinical Study - The AID-JUNCT Trial

This study will test whether once‑weekly tirzepatide added to automated insulin delivery improves blood sugar control in adults with type 1 diabetes.

Quick facts

• Phase: Phase 3
• Study type: Interventional
• Enrollment: 42 (estimated)
• Ages: 18 Years to 65 Years
• Sex: All
• Sponsor: University of Bern (Academic / other)
• Drugs / interventions: chemotherapy, radiation
• Locations: 3 sites (Chêne-Bougeries, Canton of Geneva and 2 other locations)
• Trial ID: NCT06630585 on ClinicalTrials.gov

What this trial studies

This is a prospective, randomized, open‑label Phase 3 study enrolling 42 adults (18–65 years) with type 1 diabetes for at least 12 months who have been using automated insulin delivery for ≥3 months, have HbA1c 6.5–10% and BMI ≥23 kg/m2. Participants are randomized 1:1 to once‑weekly tirzepatide (titrated from 2.5 mg to 5.0 mg) or continued standard of care for 12 weeks of treatment. The primary endpoint is change in continuous glucose monitoring (CGM) percent time in range (3.9–10.0 mmol/L) from baseline to 12 weeks, with secondary endpoints including time above and below glucose thresholds and change in BMI. The study is run at Swiss centers including University of Bern collaborators and requires regular on‑site visits and CGM data uploads.

Who should consider this trial

Good fit: Adults 18–65 years with type 1 diabetes for at least 12 months who use automated insulin delivery, have HbA1c between 6.5% and 10%, and a BMI ≥23 kg/m2 are ideal candidates.

Not a fit: People not using automated insulin delivery, with BMI <23 kg/m2, HbA1c outside the 6.5–10% range, who are pregnant, or who require other non‑insulin glucose‑lowering drugs are unlikely to benefit from this protocol.

Why it matters

Potential benefit: If successful, adding tirzepatide could increase time in target glucose range, reduce high glucose episodes, and reduce body weight and insulin needs for some adults with type 1 diabetes.

How similar studies have performed: Retrospective and observational reports suggest GLP‑1RAs and GIP/GLP‑1RA agents can improve glycemic control and reduce weight in people with type 1 diabetes, but randomized controlled trials are limited and this is among the first prospective randomized evaluations with tirzepatide.

Eligibility criteria

Inclusion Criteria:

1. Participants with diagnosed T1D for at least 12 months.
2. Aged between 18 to 65 years old (inclusive).
3. Currently on AID therapy for at least three months.
4. HbA1C higher or equal to 6.5% and less or equal to 10%.
5. BMI ≥23 kg/m2.
6. Willing to use once-weekly tirzepatide for at least 16 weeks (including four weeks of up-titration and 12 weeks of treatment)
7. Willing to wear a Dexcom G7 Sensor and share devices (AID) data uploads.
8. Willingness not to start any new non-insulin glucose-lowering agent during the trial (including metformin/biguanides, pramlintide, DPP-4 inhibitors, sodium-glucose cotransporter 2 inhibitors \[SGLT2 inhibitors\], and nutraceuticals).
9. A stable weight (± 5%) in the last 90 days or more before the screening and agree to not initiate a diet and/or exercise program during the study to reduce body weight other than the lifestyle and dietary measures for diabetes treatment.
10. Females with childbearing potential and males (if apply) must be willing to use reliable contraceptive methods (for the contraceptives study guidelines. See Annex 7 of the protocol)
11. An understanding and willingness to follow the protocol and signed informed consent.

Exclusion Criteria:

1. History of diabetic ketoacidosis requiring hospitalization in the past six months.
2. History of severe hypoglycemic event (Level 3, defined as seizure or loss of consciousness) in the past six months.
3. Uncontrolled Diabetic retinopathy or maculopathy
4. Severe gastroparesis.
5. Less than 12 months of insulin treatment.
6. Estimated glomerular filtration rate (eGFR) lab value below 30 mL/min/1.73 m2 by the CKD-EPI formula(99).
7. Pregnancy or intention to become pregnant during the trial (See annex 7).
8. Currently breastfeeding or planning to breastfeed.
9. Currently uncontrolled seizure disorder.
10. History of allergy to GIP/GLP-1RAs or its excipients.
11. Personal or family history of multiple endocrine neoplasia type 2 (MEN-2) or medullary thyroid carcinoma.
12. Screening calcitonin above or equal to 35 ng/L.
13. Planned any surgery during the study duration.
14. Have uncontrolled hypertension (systolic BP above or equal to 160 mmHg and/or diastolic BP above or equal to 100 mmHg). If a participant is on anti-hypertensive therapies, doses must be stable for 30 days before screening. For participants with uncontrolled hypertension at the screening visit, antihypertensive medication may be started or adjusted.
15. Personal history of one of the following cardiovascular conditions (within two months before the screening): acute myocardial infarction, cerebrovascular accident (stroke), unstable angina, or hospitalization due to congestive heart failure (CHF).
16. Conditions that may increase the risk of induced hypoglycemia, such as CHF with NYHA Functional Classification III or IV or adrenal insufficiency.
17. Have a history of documented human immunodeficiency virus (HIV) infection.
18. Have an uncontrolled cardiac arrhythmia based on an electrocardiogram (ECG) at the screening time and the investigator's discretion.
19. Cystic fibrosis.
20. Patient with a history of gastric bypass (bariatric) surgery, sleeve gastrectomy, or restrictive bariatric surgery, such as Lap-Band® or gastric banding.
21. Uncontrolled thyroid disease as judged by the investigator
22. Serum triglycerides higher than 5.7 mmol/L (500 mg/dL) at the screening. If a participant is on lipid-lowering therapies, doses must be stable for 30 days before screening.
23. Personal history of acute or chronic pancreatitis. A participant with a history of acute pancreatitis caused by gallstones may be included in the study if the participant has had a cholecystectomy to resolve the problem.
24. Acute or chronic hepatitis other than MASLD.
25. Have a history of symptomatic gallbladder disease within the past two years (unless the participant has had a cholecystectomy to resolve the problem).
26. History of malignancy requiring chemotherapy, surgery, or radiation (other than basal or squamous cell skin cancer, in situ carcinomas of the cervix, or in situ prostate cancer) in the previous five years.
27. Active or unstable major depressive disorder (MDD) or other severe psychiatric disorder (such as known drug or alcohol abuse, diagnosed eating disorder, or any other uncontrolled psychiatric disorder) that, in the investigator's opinion, may preclude the participant from following and completing the protocol.
28. Treatment with non-insulin glucose-lowering agents other than metformin (on a stable dose 30 days before the study)
29. Weight loss medications in the past three months.
30. Participants who are anticipated to receive, are receiving, or have received within three months before the screening (more than two weeks and more or equal to 10mg prednisolone-equivalent) chronic systemic glucocorticoid therapy (excluding topical, intraocular, intranasal, single intraarticular injection, or inhaled preparations).
31. Have current treatment with (or history of, within three months before screening) medications that may significantly affect glucose metabolism.
32. Use of investigational drugs within five half-lives before screening.
33. Participation in another study with an investigational drug within the 30 days preceding and during the present study.
34. Current enrollment in another clinical trial unless approved by the investigator of both studies and if the clinical trial is a non-interventional registry trial.
35. Have evidence of a significant active, uncontrolled medical condition or a history of any medical problem capable of constituting a risk when using the study devices or interfering with following study procedures or the interpretation of data, as judged by the study physician at screening.
36. The enrolment of the investigator, his/her family members, employees, and other dependent persons.

Where this trial is running

Chêne-Bougeries, Canton of Geneva and 2 other locations

• DiaCenTRE - Hirslanden Clinique des Grangettes — Chêne-Bougeries, Canton of Geneva, Switzerland (Recruiting)
• Kantonsspital Olten — Olten, Canton of Solothurn, Switzerland (Recruiting)
• Luzerner Kantonspital — Lucerne, Switzerland (Recruiting)

Study contacts

• Principal investigator: Thomas Zueger, PD Dr. med. — Kantonsspital Olten
• Study coordinator: Jose F Garcia-Tirado, PhD

Conditions Type 1 Diabetes; Type 1 diabetes; Adjuvant therapy; Incretins; GIP/GLP-1RA