Effect of Tirzepatide and Bimagrumab on Body Composition, Insulin Sensitivity, and Bone in Adults With Obesity
1 other identifier
interventional
63
1 country
1
Brief Summary
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.
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at P25-P50 for phase_2 obesity
Started Nov 2025
Typical duration for phase_2 obesity
1 active site
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
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Study Timeline
Key milestones and dates
First Submitted
Initial submission to the registry
June 27, 2023
CompletedFirst Posted
Study publicly available on registry
July 6, 2023
CompletedStudy Start
First participant enrolled
November 5, 2025
CompletedPrimary Completion
Last participant's last visit for primary outcome
December 31, 2028
ExpectedStudy Completion
Last participant's last visit for all outcomes
March 31, 2029
March 27, 2026
March 1, 2026
3.2 years
June 27, 2023
March 25, 2026
Conditions
Outcome Measures
Primary Outcomes (1)
Change in number of kilograms of lean mass by dual-energy x-ray absorptiometry
Change in number of kilograms of lean mass by dual-energy x-ray absorptiometry in tirzepatide + bimagrumab vs. tirzepatide groups
52 weeks
Study Arms (3)
Tirzepatide + bimagrumab
EXPERIMENTALTirzepatide + placebo
ACTIVE COMPARATORBimagrumab + placebo
ACTIVE COMPARATORInterventions
Lifestyle and nutrition counseling consistent with current guidelines for weight management
Elemental calcium 1200 mg + vitamin D3 800 IU PO daily
Eligibility Criteria
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
- Uncontrolled thyroid disease, defined as abnormal TSH with abnormal fT4
- Any chronic active infection (e.g., HIV, hepatitis B or C) or hepatitis C treatment within the previous 6 months
- Known history or presence of severe active acute or chronic liver disease (e.g., cirrhosis) or conditions with hepatotoxic potential (e.g., gallbladder or bile duct disease, acute or chronic pancreatitis, exocrine pancreatic insufficiency)
- Active clinically significant gastric emptying abnormality or chronic use of a drug(s) that directly affect GI motility
- History of calcium oxalate kidney stones
- History of clinically significant arrhythmias, unstable angina, myocardial infarction, stroke, coronary artery bypass graft surgery, percutaneous coronary intervention, heart failure, valve disorders or defect, pulmonary hypertension, chronic hypotension (\<100/50), or chronic uncontrolled hypertension (\>160/100)
- Tachycardia, defined as heart rate \>100 bpm after 5 minutes resting in a sitting position
- +26 more criteria
Contact the study team to confirm eligibility.
Sponsors & Collaborators
Study Sites (1)
Massachusetts General Hospital
Boston, Massachusetts, 02114, United States
MeSH Terms
Conditions
Interventions
Condition Hierarchy (Ancestors)
Intervention Hierarchy (Ancestors)
Central Study Contacts
Study Design
- Study Type
- interventional
- Phase
- phase 2
- Allocation
- RANDOMIZED
- Masking
- QUADRUPLE
- Who Masked
- PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
- Masking Details
- Eligible participants will be randomized in 1:1:1 ratio to tirzepatide 15mg SQ qweek + bimagrumab 300mg SQ qweek, tirzepatide 15mg SQ week, or bimagrumab 300mg SQ qweek,
- Purpose
- TREATMENT
- Intervention Model
- PARALLEL
- Sponsor Type
- OTHER
- Responsible Party
- PRINCIPAL INVESTIGATOR
- PI Title
- Assistant Professor of Medicine
Study Record Dates
First Submitted
June 27, 2023
First Posted
July 6, 2023
Study Start
November 5, 2025
Primary Completion (Estimated)
December 31, 2028
Study Completion (Estimated)
March 31, 2029
Last Updated
March 27, 2026
Record last verified: 2026-03