AzTrials
AzTrials

ObesityPhase 2NCT05933499

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

A Phase 2 study testing Bimagrumab, Tirzepatide and Calcium/Vitamin D in people with Obesity, run by Massachusetts General Hospital at 1 site in United States.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record
Search all trials

Trial 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… Read more about this study

Who is it for?
Ages 18 years and older
Conditions the study is for
Obesity
What is being tested?
Bimagrumab, Tirzepatide and Calcium/Vitamin D
Could I receive a placebo?
No, everyone receives an active treatment
How many people
63 participants
Where
1 siteUnited States
Study dates
5 Nov 2025to 31 Mar 2029
Phase
Phase 2
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • 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

Who cannot join

  • 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
Show all 44Show fewer
  • 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
  • History of malignancy of any organ system (other than localized squamous or basal cell carcinoma of the skin), treated or untreated, within the previous 5 years
  • Confirmed diagnosis of current, significant psychiatric disease (e.g., dementia, Alzheimer's disease, schizophrenia, or bipolar disorder). Individuals with adequately treated depression on stable treatment for at least 3 months are eligible.
  • Prior history of suicide attempt
  • PHQ-9 score ≥ 15 at screening
  • Personal or family history of multiple endocrine neoplasia 2A or 2B or medullary thyroid cancer
  • Active alcohol, drug, or tobacco abuse. For alcohol, an average weekly alcohol intake that exceeds 14 units per week (males) or 7 units per week (females) [1 unit = 12 oz or 260 mL of beer; 5 oz or 150 mL of wine; 1.5 oz or 45 mL of distilled spirits] is exclusionary.
  • Cannabis/THC use greater than once a week over the past three months and unwilling to abstain from use of cannabis/THC products for the duration of the study
  • Have obesity induced by other endocrinologic disorders (e.g., Cushing syndrome) or diagnosed monogenetic or syndromic forms of obesity (e.g., Melanocortin 4 Receptor deficiency or Prader Willi syndrome)
  • History of weight loss surgery or planned weight loss surgery during the trial period
  • Use of any anti-obesity medication, nutritional supplement, or over the counter (OTC) product for weight loss within the previous 6 months or during study participation
  • Any new dietary intervention or exercise regimen for weight loss started within the previous 3 months
  • Weight instability of >5kg within the previous 3 months
  • Weight > 150kg due to limitations of radiology imaging machines
  • Use of medications known or suspected to induce weight gain within the previous 3 months or during study participation (e.g., anti-androgens, gonadotropin releasing hormone (GnRH) analogs, some anticonvulsant and psychotropic medications (excluding anti-depressant medication) and oral glucocorticoids)
  • Use of skeletal muscle anabolic agents within the previous 3 months or during study participation (e.g., hormones such as growth hormone or testosterone, nutritional supplements (other than protein) and over-the-counter products labeled as muscle anabolic agents)
  • Treatment with glucose-lowering agent(s) within 90 days before screening
  • History of hypersensitivity to monoclonal antibodies or drugs in the same compound class as the study drugs
  • History of fragility fracture or BMD T-score ≤ -2.5 in participants > 50 years old
  • Use of IV bisphosphonates within the previous 2 years or other osteoporosis medications within the previous 12 months or during study participation
  • Not able or willing to comply with dietary and lifestyle intervention for weight loss, including history of clinically significant condition that precludes regular walking for exercise or contraindication to following a 500-calorie daily deficit, high protein diet
  • Women who are pregnant or breastfeeding
  • Women of child-bearing potential, defined as women physiologically capable of becoming pregnant, unless they are using an intrauterine device (IUD) from at least 3 months before the baseline visit through at least 4 months after the last drug dose and an additional contraceptive (barrier) method from screening through at least 4 months after the last drug dose. Women not of child-bearing potential are defined as individuals who (1) have a congenital anomaly such as Mullerian agenesis, resulting in confirmed infertility, (2) are infertile due to surgical sterilization (defined as documented hysterectomy, bilateral salpingo-oophorectomy, bilateral salpingectomy, or bilateral oophorectomy), or (3) are post-menopausal. The following groups of women are eligible to participate: (a) women who are s/p surgical bilateral oophorectomy or total hysterectomy at least 6 weeks before taking study treatment, (b) women who have an IUD (see additional criteria above), (c) women who are s/p tubal ligation provided that they use an additional barrier form of contraception from screening through at least 4 months after the last drug dose, (d) women who are post-menopausal defined as ≥12 months of spontaneous amenorrhea with appropriate clinical and hormonal profile (e.g., age-appropriate, history of vasomotor symptoms, and/or FSH >40 IU/L), (e) have a congenital anomaly resulting in confirmed infertility, and (f) do not have a history of sexual activity that could lead to pregnancy (i.e., total abstinence has been and is their preferred lifestyle or same-sex partners only).
  • For men, morning serum testosterone less than 200 ng/dL
  • Concurrently enrolled in any other type of medical research judged to be scientifically or medically incompatible with this study
  • Plans to move out of the study area within 16 months, or be out of the study area for >4 weeks, continuously
  • Routine MRI exclusion
  • Donation or loss of 400 mL or more of blood within past 2 months or plasma donation (> 250 mL) within past 2 weeks
  • Major surgery in the trial period
  • Any disorder, unwillingness, or inability not covered by any of the other exclusion criteria, which in the Investigator's opinion, might jeopardize the subject's safety or compliance with the protocol

Trial locations and contacts

1 site in 1 country. Contact the study team or a site near you to ask about taking part.

Melanie S Haines, MD contact

617-726-3870

mshaines@mgh.harvard.edu

United States1 site, 1 recruiting

  • Massachusetts General Hospital

    Boston, Massachusetts, 02114

    Melanie Haines, MD, 617-726-3870, mshaines@mgh.harvard.edu

    Recruiting

Other trials in United States

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.

Conditions
Obesity
Being tested
Bimagrumab, Tirzepatide, Calcium/Vitamin D, Lifestyle and nutrition counseling
Medical subject headings
Obesity

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • BimagrumabDrug

    SQ bimagrumab 300mg qweek

  • TirzepatideDrug

    SQ tirzepatide 15mg qweek

  • Calcium/Vitamin DDietary supplement

    Elemental calcium 1200 mg + vitamin D3 800 IU PO daily

  • Lifestyle and nutrition counselingBehavioural

    Lifestyle and nutrition counseling consistent with current guidelines for weight management

Study groups in NCT05933499
Study groupRoleWhat they receive
Tirzepatide + bimagrumabExperimentalNot described
Receives: Drug: Bimagrumab; Drug: Tirzepatide; Dietary Supplement: Calcium/Vitamin D; Behavioral: Lifestyle and nutrition counseling
Tirzepatide + placeboActive comparatorNot described
Receives: Drug: Tirzepatide; Dietary Supplement: Calcium/Vitamin D; Behavioral: Lifestyle and nutrition counseling
Bimagrumab + placeboActive comparatorNot described
Receives: Drug: Bimagrumab; Dietary Supplement: Calcium/Vitamin D; Behavioral: Lifestyle and nutrition counseling

What is being measured

The primary outcome is the main question the study is designed to answer.

  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

    Measured: 52 weeks

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted6 Jul 2023
  2. Study start5 Nov 2025
  3. Primary completion31 Dec 2028 (estimated)
  4. Study completion31 Mar 2029 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 2
Primary purpose
Treatment
Allocation
Randomised
Intervention model
Parallel groups
Masking
Quadruple blind
Who is masked
Participant, Care provider, Investigator, Outcomes assessor
Enrolment
63 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT05933499
Sponsor's protocol ID
2023P001334
Status last verified
Mar 2026
First submitted
27 Jun 2023
Last updated
27 Mar 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No

Questions about this trial

What is this clinical trial studying?

A Phase 2 study testing Bimagrumab, Tirzepatide and Calcium/Vitamin D in people with Obesity, run by Massachusetts General Hospital at 1 site in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 3 inclusion and 44 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: looking for participants now, as of the sponsor's last update on 27 Mar 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact Melanie S Haines, MD (617-726-3870, mshaines@mgh.harvard.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Change in number of kilograms of lean mass by dual-energy x-ray absorptiometry (time frame: 52 weeks). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05933499.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 27 Mar 2026.

AzTrials uses cookies for analytics and advertising. You can accept or reject them; the site works either way. Privacy Policy.

Free account

Log in to keep searching

You’ve used your 3 free searches. AzTrials is free: log in or create a free account to keep searching clinical trials and save the ones you want to follow.

Create a free accountLog in