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

NCT07142707 | Recruiting Phase 1 FDA Drug

• 1 other identifier: MBX-4O3001
• Study Type: interventional
• Target: 124
• Locations: 1 country
• Sites: 2

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

Keywords

Body Weight; Body Mass Index; Overweight; Nutrition Disorders

Outcome Measures

Primary Outcomes (1)

• Number of participants with Treatment Emergent Adverse Events (TEAEs)

  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 Arms (4)

MBX 4291 (Part A)

EXPERIMENTAL

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

Drug: MBX 4291

MBX 4291 (Part B)

EXPERIMENTAL

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

Drug: MBX 4291

MBX 4291 (Part C)

EXPERIMENTAL

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

Drug: MBX 4291

Placebo

PLACEBO COMPARATOR

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

Drug: Placebo

Interventions

MBX 4291 DRUG

MBX 4291 will be administered subcutaneously (SC)

MBX 4291 (Part A); MBX 4291 (Part B); MBX 4291 (Part C)

Placebo DRUG

Placebo: Placebo will be administered subcutaneously (SC)

Placebo

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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.

You may not qualify if:

• 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.

Sponsors & Collaborators

• MBX Biosciences: lead

Study Sites (2)

MBX Biosciences Investigational Site

Lexington, Kentucky, 40509, United States

RECRUITING

MBX Biosciences Investigational Site

Knoxville, Tennessee, 37920, United States

RECRUITING

MeSH Terms

Conditions

Obesity; Body Weight; Overweight; Nutrition Disorders

Condition Hierarchy (Ancestors)

Overnutrition; Nutritional and Metabolic Diseases; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Central Study Contacts

Elisa Fabbrini, MD, PhD

CONTACT

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

Stewart Hallett

CONTACT

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

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: August 4, 2025
• First Posted: August 27, 2025
• Study Start: September 3, 2025
• Primary Completion (Estimated): October 30, 2026
• Study Completion (Estimated): October 30, 2026
• Last Updated: April 28, 2026

Record last verified: 2026-04

Locations

US (2)