A Study of Tirzepatide (LY3298176) in Participants With Type 1 Diabetes Mellitus and Overweight or Obesity

What Was Tested

In this phase 1 trial, researchers set out to test Tirzepatide.

The main purpose of this study is to learn more how tirzepatide affects stomach emptying in participants with Type 1 Diabetes Mellitus (T1DM) and overweight or obesity.

Participation in this study will last about 8 weeks, including screening and follow-up.

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

Participants will receive tirzepatide administered subcutaneously (SC) and acetaminophen administered orally.

Participants will receive placebo administered SC and acetaminophen administered orally.

The registry classes the interventions as drug.

Who Took Part

The registry lists 18 planned participants were the target.

It was open to people of any sex aged from 18 years up to 70 years.

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

Examples of who could join: Have a diagnosis of type 1 diabetes mellitus (T1DM) and have been treated with insulin for at least 1 year prior to screening. Have a body mass index (BMI) greater than or equal to 25.0 kilograms per square meter (kg/m2) at screening. Are of stable weight, that is a self-reported change of 5 kg or less, for at least 90 days prior to screening.

The full record lists 3 inclusion and 3 exclusion criteria; among the exclusions: have undergone weight loss surgery such as gastric bypass (bariatric) surgery or restrictive bariatric surgery; have known allergies or intolerance to acetaminophen, tirzepatide, or glucagon-like peptide-1 (glp-1) receptor agonists.

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.

As a double-blind Tirzepatide study, the assignments were hidden from both participants and investigators until the end.

Those kept unaware of assignments: participant and investigator.

It started in 2026-09-11 with completion listed for 2026-12.

It ran at 1 site in United States.

Its stated primary purpose is basic science.

What Was Measured

Researchers chose this as the main measure: PK: Area Under the Concentration Versus Time Curve from Time Zero to Time t (AUC0-tlast) of Acetaminophen. PK: Maximum Observed Drug Concentration (Cmax) of Acetaminophen.

It also tracked 4 secondary outcomes, for example PK: Area Under the Concentration Versus Time Curve from Time Zero to Infinity (AUC0-∞) of Tirzepatide, PK: Area Under the Concentration Versus Time Curve from Time Zero to Time t (AUC0-tlast) of Tirzepatide, PK: Maximum Observed Drug Concentration (Cmax) of Tirzepatide and PK: Time of Maximum Observed Drug Concentration (Tmax) of Tirzepatide.

What This Means in Plain Language

Put simply, this is a phase 1, randomized trial of Tirzepatide in 18 people.

Its size is small, so on its own it can only give an early look.

It is still recruiting; no results are posted to the registry yet, so nothing here describes outcomes.

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