A Study of Retatrutide (LY3437943) in the Maintenance of Weight Reduction in Individuals With Obesity

What Was Tested

In this phase 3 trial, researchers set out to test Retatrutide.

This is a study of retatrutide in participants with obesity.

The main purpose is to learn more about how retatrutide maintains body weight loss.

It had three arms (groups): one (experimental), one (experimental) and one (placebo comparator).

The registry classes the interventions as drug.

Who Took Part

643 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.

The full record lists 1 inclusion and 13 exclusion criteria; among the exclusions: have a self-reported change in body weight \>5 kilograms (kg) (11 pounds) within 90 days before screening; have a prior or planned surgical treatment for obesity; have a prior or planned endoscopic procedure and/or device-based therapy for obesity.

How the Study Was Run

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

Random assignment meant chance, not the researchers, decided who got Retatrutide and who got the comparison, which limits bias.

Groups ran in parallel: each of the participants stayed in one arm throughout.

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

Those kept unaware of assignments: participant and investigator.

It started in 2025-03-05 with completion listed for 2028-04.

It ran at 53 sites in United States (33), United Kingdom (12) and Canada (8).

Its stated primary purpose is treatment.

What Was Measured

The main thing measured (primary outcome): Percent Change from Baseline in Body Weight (time frame: Week 0, Week 116).

It also tracked 3 secondary outcomes, for example Change from Baseline in Waist Circumference and Change from Baseline in Impact of Weight on Quality of Life-Lite Clinical Trials Version (IWQOL-Lite-CT).

What This Means in Plain Language

Put simply, this is a phase 3, randomized trial of Retatrutide in 643 people.

With 643 participants it is a large trial for this field.

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

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