A Long-Term Study of Tirzepatide (LY3298176) in Adults With Type 1 Diabetes and Obesity or Overweight

What Was Tested

The trial (phase 3) is built around Tirzepatide.

Participation in the study will last about 20 months.

It had two arms (groups): Tirzepatide (experimental) and Placebo (placebo comparator).

Participants will receive tirzepatide subcutaneously (SC).

Participants will receive placebo SC.

The registry classes the interventions as drug.

Who Took Part

465 planned participants were the target.

It was open to people of any sex aged from 18 years with no upper age limit.

Healthy volunteers were not accepted; participants needed the condition being studied.

Examples of who could join: Have type 1 diabetes and on insulin treatment for at least one year prior to screening. Have a body mass index (BMI) of ≥25 kilograms per square meter (kg/m2) at screening. Are of stable weight for at least 90 days prior to screening and agree to not start an intensive diet or exercise program during the study.

The full record lists 4 inclusion and 5 exclusion criteria; among the exclusions: have experienced one or more events of severe hypoglycemia during the period of 90 days prior to screening and until randomization; are currently receiving or planning to receive treatment for diabetic retinopathy and/or macular edema; have had chronic or acute pancreatitis.

How the Study Was Run

Design: randomized, parallel-group and double-blind.

The participants were allocated by chance, so the Tirzepatide group and the comparison group should start out alike.

The Tirzepatide group and the comparison group ran side by side rather than switching.

Blinding on both sides kept the participants and researchers unaware of who received Tirzepatide.

Those kept unaware of assignments: participant and investigator.

It started in 2025-05-12 with completion listed for 2026-11.

It ran at 79 sites in United States (18), Mexico (9), Argentina (8), Brazil (8), France (8) and Romania (8).

Its stated primary purpose is treatment.

What Was Measured

The main thing measured (primary outcome): Change from Baseline in Hemoglobin A1c (HbA1c) (time frame: Baseline, Week 40).

It also tracked 14 secondary outcomes, for example Change from Baseline in HbA1c, Change from Baseline in Body Weight, Percent Change from Baseline in Body Weight, Change from Baseline in Waist Circumference, Change from Baseline in Systolic Blood Pressure (SBP) and Percent Change from Baseline in Fasting Triglycerides.

What This Means in Plain Language

Put simply, this is a phase 3, randomized trial of Tirzepatide in 465 people.

Its status is active not recruiting; no results are posted to the registry yet, so nothing here describes outcomes.

More context: the Tirzepatide compound page, all human trials.