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NCT Number: NCT07142707

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

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.

Recruiting

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Key information

Conditions

Obesity Body Weight Nutrition Disorders Nutritional and Metabolic Diseases Overnutrition Overweight Pathological Conditions, Signs and Symptoms Signs and Symptoms

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 1

Primary location

MBX Biosciences Investigational Site, Doral, Florida, United States

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About this study

This is a Phase 1, double-blind, placebo-controlled first-in-human study to evaluate the single ascending doses (SAD) and multiple ascending doses (MAD) of MBX 4291 in participants with obesity, who are otherwise generally healthy. Approximately 124 patients aged 18 to 65 years old will be enrolled.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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.

Treatment and study plan

MBX 4291

Drug

MBX 4291 will be administered subcutaneously (SC)

Placebo

Drug

Placebo: Placebo will be administered subcutaneously (SC)

Primary outcomes

  1. Number of participants with Treatment Emergent Adverse Events (TEAEs)

    Time frame: 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.

Study contacts

Contact information is provided by the study sponsor or research team.

Elisa Fabbrini, MD, PhD

CONTACT

[email protected]

844-877-4473

Stewart Hallett

CONTACT

[email protected]

844-877-4473

Sponsors and collaborators

Lead sponsor

MBX Biosciences

Industry

Registry information

Official study title

A Randomized, Double-blind, Placebo-controlled First-in-human Study to Evaluate the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of Single and Multiple Ascending Doses of MBX 4291 in Adult Participants With Obesity

Important dates

Study start
2025
Primary completion
2026
Study completion
2026
First posted
Aug 27, 2025
Registry last updated
Jun 9, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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