RecruitingPhase 1

A Study to Evaluate the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of MBX 4291 in Adult Participants With Obesity

United States124 participantsStarted 2025-09-03

Plain-language summary

The purpose of this study is to evaluate the safety and tolerability of single and multiple subcutaneous (SC) doses of MBX 4291 in adults with obesity.

Who can participate

Age range

18 Years – 65 Years

Sex

ALL

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion Criteria: * Age of \>18 to ≤65 years at the time of signing the informed consent. * Has a BMI of ≥30 to \<50 kg/m2 at screening and baseline. * Weight-stable, i.e., no more than ±5% change in body weight for at least 3 months prior to screening and between screening and baseline. Exclusion Criteria: * History of, or currently active, significant illness or medical disorders that in the opinion of the investigator may preclude participants from participating in the study. * History of currently active pancreatitis, type I and type II diabetes. * Secondary causes of obesity, including but not limited to hypothalamic, monogenic, syndromic, or endocrine causes. * A personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia syndrome type 2.

Questions worth asking your doctor

Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.

1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?

Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.

Questions for the trial coordinator

The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.

1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?

A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.

What they're measuring

Number of participants with Treatment Emergent Adverse Events (TEAEs)

Timeframe: The total duration of study participation for each participant including screening, treatment period, follow-up, and end of study visit will be up to 91 days in Part A, up to 99 days in Part B, and up to 148 days in Part C.

Trial details

NCT IDNCT07142707

SponsorMBX Biosciences

Sponsor typeINDUSTRY

Study typeINTERVENTIONAL

Primary completion2026-10-30

Contact for this trial

Elisa Fabbrini, MD, PhD

844-877-4473 MBX4291.Clinicaltrials@mbxbio.com

View on ClinicalTrials.gov More Obesity trials