Effect of Tirzepatide and Bimagrumab on Body Composition, Insulin Sensitivity, and Bone in Adults With Obesity
Recruiting · Boston, Massachusetts
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Your choice
Voluntary — you can stop anytime
What is 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.
It is , overseen by an independent and licensed medical staff.
Read the full clinical description
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.
Who this study is looking for
In plain language, from the study's own rules. The study team confirms the full details with you — this isn't a final yes or no.
✅ You may be able to join if…
- •Adults with obesity (BMI ≥30) or BMI ≥27 with at least one weight-related medical condition
- •Someone who tried to lose weight through behavior changes but did not succeed
- •They have an established primary care provider
- •They can follow the diet and lifestyle plan for weight loss
- •They are able to take part in the study (including required visits and tests)
🚫 You may not be able to join if…
- •People with diabetes (by self-report/diabetes medicines, HbA1c ≥6.5%, or fasting glucose ≥126 mg/dL)
- •People with significant liver test problems (very high ALT/AST/alk phos) or other serious liver/pancreas problems
- •People with chronic kidney disease (eGFR <45 mL/min) or certain serious blood count problems
- •People with uncontrolled thyroid disease, significant active stomach emptying problems, or active major infections (like HIV or hepatitis B/C)
- •People who are pregnant or breastfeeding, or who cannot use reliable birth control if they could become pregnant
Are you a good fit?
Simplified highlights. The study team always confirms the full details with you.
- ✓Adults roughly 18–any age
- ✓A BMI around 30 or higher
- ✓Have Obesity / overweight
- !Some conditions may not be a fit: Heart / cardiovascular disease, High blood pressure, Kidney disease
- !Not for people who are pregnant or breastfeeding
What to expect, step by step
- 1
Usually a few weeks
The study team checks whether the study is a good fit for you, with a visit and sometimes lab tests. You can ask any questions before deciding.
- 2
Treatment
If you join and choose to continue, you receive the study treatment and are watched closely by medical staff.
- 3
Follow-up
After treatment, the team checks on your health and confirms the visit schedule with you. You can leave the study at any point.
Has this treatment been tested before?
Yes. This treatment has already been through earlier human studies for safety before reaching this stage.
What you need to know before you apply
What is this study testing?+
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.
Is it safe? Who makes sure of that?+
This is a mid-stage study (Phase 2), looking at safety and whether the treatment works. Every study is reviewed and monitored by an independent ethics board (called an IRB) whose job is to protect participants, and care is overseen by licensed medical staff. You'll be told the known risks before you agree to anything, and you can stop at any time.
Will I get a placebo instead of the real treatment?+
Some studies compare a treatment against a placebo (an inactive version), and some don't. If this one does, the study team will explain your chances of receiving the active treatment before you decide. Nothing is hidden from you.
Do I have to stop taking my current medications?+
It depends on the study. Some let you stay on your current medications and some ask you to adjust them. Never stop a medication on your own — the study team will review everything with you first.
Does it cost anything? Will I be paid?+
The study treatment and study-related visits are provided at no cost to you. Some studies also pay for your time; the coordinator can tell you if this one does. You should never be asked to pay to take part.
Do I need insurance? Will anyone ask about my immigration status?+
No. You do not need health insurance to take part in a research study, and you will not be asked about your immigration status to join. Taking part is about whether you're a medical fit for the study.
What if English isn't my first language?+
You have the right to understand everything before you agree. Study sites can often provide materials or an interpreter in your language — you can ask the coordinator for one.
Is my information private?+
Yes. Your health information is only shared with the study sites you choose to be contacted by, and only to help match and enroll you. It is never sold, and you can ask us to delete it at any time.
Some requirements (like specific lab values or timing) are confirmed directly by the study team, not by us.
Source: ClinicalTrials.gov · NCT05933499 · Locations: Massachusetts