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Effect of Tirzepatide and Bimagrumab on Body Composition, Insulin Sensitivity, and Bone in Adults With Obesity

NCT05933499 · Recruiting

Last updated 2026-05-28

This clinical trial is testing whether the medications tirzepatide and bimagrumab affect body composition, insulin sensitivity, and bone health in adults with obesity.

Status Recruiting Currently enrolling participants.
Phase Phase 2 Tests whether it works and watches safety in a moderate group.
Type Interventional (clinical trial)
Design Randomized, quadruple-blind treatment study
Participants 63 people Planned (estimated).
Who can join Ages 18+ · all sexes
Timeline Started 2025-11 · est. completion 2029-03
Where 1 site · United States

What this study is testing ClinicalTrials.gov NCT05933499 ↗

Description as written by the study sponsor.

In adults with obesity seeking treatment, weight loss would ideally be composed almost exclusively of fat mass. However, loss of muscle mass and bone are unintentional consequences of weight loss, which may have negative effects on health by lessening improvements in glucose and insulin levels, reducing resting metabolic rate, and increasing the risk of falls and fractures. Data in animals and humans suggest that bimagrumab, an investigational new drug for obesity that inhibits the activin type II receptor (ActRII) inhibitor, may help maximize loss of fat mass while maintaining muscle mass when used in combination with a glucagon-like peptide 1 receptor agonist (GLP-1 RA). The investigators hypothesize that in a randomized, placebo-controlled trial of 63 adults with obesity randomized to tirzepatide (GLP-1/GIP RA) + bimagrumab, tirzepatide alone, or bimagrumab alone, the combination of tirzepatide + bimagrumab will result in improvements in muscle, fat, and bone compared to tirzepatide alone or bimagrumab alone when given in addition to a lifestyle intervention for weight loss over 52 weeks.

Treatments tested

Main thing measuredChange in number of kilograms of lean mass by dual-energy x-ray absorptiometry
SponsorMassachusetts General Hospital
Conditions studiedObesity
GLP-1 drugs tirzepatide

Full protocol, eligibility, and contacts on ClinicalTrials.gov NCT05933499 ↗