Effect of Tirzepatide and Bimagrumab on Body Composition, Insulin Sensitivity, and Bone in Adults With Obesity
Eligible age
18+ yrs
Accepts
All genders
Locations
1 state
Healthy volunteers
No
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About this study
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.
Sponsor: Massachusetts General Hospital
You may qualify if…
- ✓ BMI ≥30 kg/m2 or ≥27kg/m2 with at least one weight-related medical condition
- ✓ Have a history of at least one self-reported unsuccessful behavioral effort to lose body weight
- ✓ Have an established primary care provider
You may not qualify if…
- ✕ Current or prior history of diabetes mellitus based on self-report, use of diabetes medications, HbA1c ≥6.5%, or fasting glucose ≥126 mg/dL
- ✕ Any single serum transaminase level (i.e., ALT, AST, alk phos) ≥3x the upper limit of normal (ULN)
- ✕ Serum lipase and/or amylase levels ≥2x ULN
- ✕ Serum bilirubin level \>1.6 mg/dL
- ✕ Chronic kidney disease (e.g., estimated glomerular filtration rate (eGFR) \< 45 mL/min)
- ✕ Total WBC \<3000/μL, neutrophils \<1500/μL, hemoglobin \<12 g/dL, or platelet count \<100,000/μL
- ✕ Significant coagulopathy, e.g., PT/INR \>1.5
- ✕ History of familial hypertriglyceridemia or serum fasting triglyceride \>500 mg/dL
Where it's recruiting
Boston
Source: ClinicalTrials.gov · NCT05933499 · last updated 2026-03-27