Recruiting
Phase 1

MBX 4291

Sponsor:

MBX Biosciences

Code:

NCT07142707

Conditions

Obesity

Eligibility Criteria

Sex: All

Age: 18 - 65

Healthy Volunteers: Not accepted

Interventions

MBX 4291

Placebo

Study Details

Brief 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.

Conditions

Obesity

Study ID

NCT07142707

Start date

Sep 3, 2025

Status verified date

Jun, 2026

Completion date

Oct 30, 2026

Anticipated

Primary completion date

Oct 30, 2026

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18 - 65

Healthy Volunteers: Not accepted

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.

Study Design

Enrollment

124 participants

Anticipated

Allocation

Randomized

Intervention Model

Parallel Assignment

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: MBX 4291 (Part A)

Participants will be administered single ascending doses of MBX 4291, or matching placebo.

experimental: MBX 4291 (Part B)

Participants will be administered multiple ascending doses of MBX 4291, or matching placebo.

experimental: MBX 4291 (Part C)

Participants will be administered multiple ascending doses of MBX 4291, or matching placebo.

placebo comparator: Placebo

Participants will be administered single or multiple ascending doses of placebo.

Interventions

MBX 4291

MBX 4291 will be administered subcutaneously (SC)

Placebo

Placebo: Placebo will be administered subcutaneously (SC)

Primary outcome measure

  • 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. ]

Central Contacts and Locations

Central contacts

Elisa Fabbrini, MD, PhD

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

Stewart Hallett

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

Locations

MBX Biosciences Investigational Site

Recruiting

Doral, Florida, United States, 33172

MBX Biosciences Investigational Site

Recruiting

Lexington, Kentucky, United States, 40509

MBX Biosciences Investigational Site

Recruiting

Kansas City, Missouri, United States, 64114

MBX Biosciences Investigational Site

Recruiting

Knoxville, Tennessee, United States, 37920

More Information

Sponsor

MBX Biosciences

Last update posted

Jun 9, 2026

Last verified

Jun, 2026

Keywords

  • Body Weight
  • Body Mass Index
  • Overweight
  • Nutrition Disorders

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-09. This information was provided to ClinicalTrials.gov by MBX Biosciences on 2026-06-09.