A Study of BOS-580 in Obese Subjects at Risk for, or With Biopsy-confirmed, Nonalcoholic Steatohepatitis (NASH) With an Extension

October 29, 2025 updated by: Boston Pharmaceuticals

A Phase 2a, Randomized, Blinded, Placebo-controlled Study of BOS-580 in Obese Subjects at Risk for, or With Biopsy-confirmed, Nonalcoholic Steatohepatitis (NASH) With a Single Arm Open-label Extension

This is a randomized, blinded, placebo-controlled study of Efimosfermin in obese participants at risk for, or with biopsy-confirmed, nonalcoholic steatohepatitis (NASH), with a single arm open-label extension. It includes Parts A, B, C and D.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
231

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • United States
    • Alabama
      • Birmingham, Alabama, United States, 35205
        • Central Research Associates
    • Arizona
      • Chandler, Arizona, United States, 85224
        • Arizona Liver Health
      • Peoria, Arizona, United States, 85381
        • Arizona Liver Health
      • Tucson, Arizona, United States, 85712
        • QLMC
      • Tucson, Arizona, United States, 85712
        • Arizona Liver Health
      • Tucson, Arizona, United States, 85712
        • Liver Institute PPLC
    • California
      • Canoga Park, California, United States, 91304
        • Alliance Research Institute
      • Fountain Valley, California, United States, 92708
        • Ark Clinical Research
      • Fresno, California, United States, 92720
        • Fresno Clinical Research Center
      • Montclair, California, United States, 91763
        • Catalina Research Institute
      • Orange, California, United States, 92868
        • Knowledge Research Center
      • Oxnard, California, United States, 93030
        • Fomat Medical Research
      • Rialto, California, United States, 92377
        • Inland Empire Clinical Trials
    • Florida
      • Fort Myers, Florida, United States, 33907
        • Southwest General Healthcare Center
      • Fort Myers, Florida, United States, 33912
        • Covenant Metabolic Specialists - Fort Myers
      • Hialeah Gardens, Florida, United States, 33016
        • Evolution Clinical Trials
      • Kendall, Florida, United States, 33176
        • Entrust Clinical Research Center
      • Lehigh Acres, Florida, United States, 33976
        • Galenus Group
      • Miami, Florida, United States, 33173
        • Century Research
      • Miami, Florida, United States, 33155
        • Miami Clinical Research
      • Miami, Florida, United States, 33126
        • G+C Research Group
      • Miami, Florida, United States, 33156
        • Advanced Clinical Research
      • Miami, Florida, United States, 33173
        • Admed Research
      • Miami Lakes, Florida, United States, 33014
        • Panex Clinical Research
      • Orlando, Florida, United States, 32803
        • Charter Research
      • Port Orange, Florida, United States, 32127
        • Progressive Medical Research
      • Sarasota, Florida, United States, 34240
        • Covenant Metabolic Specialists - Sarasota
    • Louisiana
      • Marrero, Louisiana, United States, 70072
        • Tandem Clinical Research
    • Missouri
      • Kansas City, Missouri, United States, 64131
        • Kansas City Research Institute
    • North Carolina
      • Fayetteville, North Carolina, United States, 28304
        • Coastal Research Institute, LLC
    • North Dakota
      • Fargo, North Dakota, United States, 58104
        • Lillestol Research LLC
    • Rhode Island
      • East Greenwich, Rhode Island, United States, 02818
        • Velocity Clinical Research
    • Texas
      • Austin, Texas, United States, 78745
        • Accelemed Research
      • Austin, Texas, United States, 78757
        • Pinnacle Clinical Research - Austin
      • Austin, Texas, United States, 78757
        • Texas Liver Institute - Austin
      • Bellaire, Texas, United States, 77401
        • Apex Mobile Clinical Research
      • Brownsville, Texas, United States, 78520
        • South Texas Research Institute-Brownsville
      • Edinburg, Texas, United States, 75839
        • South Texas Research Institute-Edinburg
      • Georgetown, Texas, United States, 78626
        • Pinnacle Clinical Research - Georgetown
      • Houston, Texas, United States, 77079
        • Houston Research Institute
      • Pearland, Texas, United States, 77584
        • LinQ Research, LLC
      • San Antonio, Texas, United States, 78229
        • Pinnacle Clinical Research - San Antonio
      • San Antonio, Texas, United States, 78215
        • American Research Corporation at Texas Liver Institute
      • San Antonio, Texas, United States, 78209
        • Quality Research, Inc
      • Waco, Texas, United States, 76710
        • Velocity Clinical Research - Waco
    • Utah
      • Salt Lake City, Utah, United States, 84117
        • Olympus Family Medicine
      • South Ogden, Utah, United States, 84405
        • South Ogden Family Medicine
    • Washington
      • Seattle, Washington, United States, 98105
        • Liver Institute Northwest

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 75 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria (Part A and Part B):

  • Participant is either male or female and 18 to 75 years of age inclusive, at the time of signing the informed consent
  • Obese participants with body mass index (BMI) of ≥ 27 kg/m^2
  • Hepatic fat fraction (HFF) measured by magnetic resonance imaging derived proton density fat fraction (MRI-PDFF) ≥8%
  • Liver fibrosis assessment based on a vibration controlled transient elastography (VCTE) liver stiffness measurement (LSM) score of 7.0 to 9.9 kPa (Part A only) inclusive or 7.0 to 20.0 kPa (Part B only) inclusive and Liver injury assessment measured by aspartate aminotransferase (AST) >25U/L. A qualifying historical biopsy (confirmed eligibility based on the central pathology read) supersedes the LSM, controlled attenuation parameter (CAP) score criteria and AST criteria.
  • Histopathologically confirmed F2 or F3 stage NASH on a diagnostic liver biopsy performed during Screening or within 6 months prior to the first day of dosing for historical biopsies (Part B only).
  • History or presence of at least 2 of 4 components of metabolic syndrome: obesity/overweight, dyslipidemia (high triglycerides and/or low high density lipoprotein [HDL]), type 2 diabetes with elevated glycated hemoglobin (HbA1c), and hypertension.

Inclusion Criteria (Part C):

  • Participant must have completed the Part B of the study.
  • Participant willing to undergo liver biopsy at Week 56
  • NASH F stage <F4 at 24 week assessment in Part B

Inclusion Criteria (Part D):

  • BMI of ≥ 25 kg/m^2
  • Liver fibrosis based on assessments taken during screening visit
  • Participant should be willing and able to undergo liver biopsy during Screening (if a historical biopsy within 12 months prior to Screening is not available) and per protocol as judged by the Investigator.
  • Other inclusion criteria may apply

Exclusion Criteria (Part A and Part B):

  • Documented clinical, laboratory or radiologic evidence of cirrhosis (compensated or decompensated)
  • Triglycerides ≥ 500 mg/dL
  • Change in body weight (more than 5% self-reported OR 5 kg self-reported change during the previous 3 months from Screening, whichever is smaller)
  • History of type 1 diabetes, diabetic ketoacidosis, or positive glutamic acid decarboxylase (GAD) auto-antibodies (latent autoimmune diabetes in adults)
  • Hemoglobin A1c > 9.5%
  • Participants with a condition that requires substantial anticoagulant medication may not be eligible for the study enrollment (e.g., deep vein thrombosis).

Exclusion Criteria (Part C):

• Participants that received their 24 week dose in Part B > 10 weeks prior to enrollment into Part C

Exclusion Criteria (Part D):

  • Other causes of chronic liver disease
  • Documented evidence or history of decompensated liver cirrhosis.
  • History of type 1 diabetes or poorly controlled type 2 diabetes.
  • History of malignancy.
  • Use of other investigational drugs.
  • Other exclusion criteria may apply

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Cohort A1: Efimosfermin Dose 1 or placebo (PBO)
Drug: Placebo
Placebo will be administered by subcutaneous injection
Drug: Efimosfermin
Efimosfermin will be administered by subcutaneous injection
Other Names:
  • BOS-580
Experimental: Cohort A2: Efimosfermin Dose 2 or PBO
Drug: Placebo
Placebo will be administered by subcutaneous injection
Drug: Efimosfermin
Efimosfermin will be administered by subcutaneous injection
Other Names:
  • BOS-580
Experimental: Cohort A3: Efimosfermin Dose 3 or PBO
Drug: Placebo
Placebo will be administered by subcutaneous injection
Drug: Efimosfermin
Efimosfermin will be administered by subcutaneous injection
Other Names:
  • BOS-580
Experimental: Cohort A4: Efimosfermin Dose 4 or PBO
Drug: Placebo
Placebo will be administered by subcutaneous injection
Drug: Efimosfermin
Efimosfermin will be administered by subcutaneous injection
Other Names:
  • BOS-580
Experimental: Cohort A5: Efimosfermin Dose 5 or PBO
Drug: Placebo
Placebo will be administered by subcutaneous injection
Drug: Efimosfermin
Efimosfermin will be administered by subcutaneous injection
Other Names:
  • BOS-580
Experimental: Part B: Efimosfermin Dose 1 or PBO
Drug: Placebo
Placebo will be administered by subcutaneous injection
Drug: Efimosfermin
Efimosfermin will be administered by subcutaneous injection
Other Names:
  • BOS-580
Experimental: Part C: Efimosfermin Dose 1
Drug: Efimosfermin
Efimosfermin will be administered by subcutaneous injection
Other Names:
  • BOS-580
Experimental: Part D: Efimosfermin Dose 6 or PBO
Drug: Placebo
Placebo will be administered by subcutaneous injection
Drug: Efimosfermin
Efimosfermin will be administered by subcutaneous injection
Other Names:
  • BOS-580
Experimental: Part D: Efimosfermin Dose 1 or PBO
Drug: Placebo
Placebo will be administered by subcutaneous injection
Drug: Efimosfermin
Efimosfermin will be administered by subcutaneous injection
Other Names:
  • BOS-580

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Part A, Part B, Part C, and Part D: Number of participants with treatment-emergent adverse events (TEAEs) and treatment-emergent serious adverse events (TESAEs)
Time Frame: Until End of study/Early Termination (Day 393)
The effects of Efimosfermin on safety and tolerability will be assessed.
Until End of study/Early Termination (Day 393)
Part A, Part B, Part C, and Part D: Changes from Baseline in systolic and diastolic blood pressure (BP)
Time Frame: Baseline, Week 12 (Day 85, Part A), Week 24 (Day 169, Part B), Week 56 (Day 393, Part C), and Weeks 36 (Day 253), and 48 (Day 337) (Part D)
The effects of Efimosfermin on safety and tolerability will be assessed.
Baseline, Week 12 (Day 85, Part A), Week 24 (Day 169, Part B), Week 56 (Day 393, Part C), and Weeks 36 (Day 253), and 48 (Day 337) (Part D)
Part A, Part B, Part C, and Part D: Changes from Baseline in heart rate
Time Frame: Baseline, Week 12 (Day 85, Part A), Week 24 (Day 169, Part B), Week 56 (Day 393, Part C), and Weeks 36 (Day 253), and 48 (Day 337) (Part D)
The effects of Efimosfermin on safety and tolerability will be assessed.
Baseline, Week 12 (Day 85, Part A), Week 24 (Day 169, Part B), Week 56 (Day 393, Part C), and Weeks 36 (Day 253), and 48 (Day 337) (Part D)
Part A, Part B, Part C, and Part D: Number of participants with Grade 3 and Grade 4 laboratory abnormalities
Time Frame: Baseline, Week 12 (Day 85, Part A), Week 24 (Day 169, Part B), Week 56 (Day 393, Part C), and Weeks 36 (Day 253), and 48 (Day 337) (Part D)
The effects of Efimosfermin on safety and tolerability will be assessed.
Baseline, Week 12 (Day 85, Part A), Week 24 (Day 169, Part B), Week 56 (Day 393, Part C), and Weeks 36 (Day 253), and 48 (Day 337) (Part D)

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Part A only: Efimosfermin serum concentration on Day 8 of the first dose
Time Frame: Day 8
The pharmacokinetics (PK) of Efimosfermin will be assessed.
Day 8
Part A only: Efimosfermin serum concentration at the end of the dosing interval (Ctrough)
Time Frame: Pre-dose at Days 15, 29, 43, 57, 71, 85 and 113 (End of study/Early termination) for bi-weekly schedule; pre-dose on Days 29, 57, 85 and 113 (End of study/Early termination) for the monthly schedule
The PK of Efimosfermin will be assessed.
Pre-dose at Days 15, 29, 43, 57, 71, 85 and 113 (End of study/Early termination) for bi-weekly schedule; pre-dose on Days 29, 57, 85 and 113 (End of study/Early termination) for the monthly schedule
Part B only: Efimosfermin serum concentration on Day 7
Time Frame: Day 7
The PK of Efimosfermin will be assessed.
Day 7
Part B and Part C: Efimosfermin serum concentration at the end of the dosing interval (Ctrough)
Time Frame: Pre-dose at Days 29, 57, 85, 113, 141, 169, 225, 253, 281, 309, 316, 323, 330, 337, 365 and at Day 393 (End of study/Early Termination)
The PK of Efimosfermin will be assessed.
Pre-dose at Days 29, 57, 85, 113, 141, 169, 225, 253, 281, 309, 316, 323, 330, 337, 365 and at Day 393 (End of study/Early Termination)
Part B and Part C: Area under the serum concentration-time curve (AUC) for Efimosfermin for one dosing interval at steady state
Time Frame: At Days 121, 127, 134, 316, 323, 330 and pre-dose at Days 141 and 337
The PK of Efimosfermin will be assessed.
At Days 121, 127, 134, 316, 323, 330 and pre-dose at Days 141 and 337

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Boston Pharmaceuticals

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
GSK Research and Development Limited

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
September 30, 2021

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
October 27, 2025

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
October 27, 2025

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
May 5, 2021

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 5, 2021

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
May 10, 2021

Study Record Updates

Last Update Posted (Estimated)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
October 30, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
October 29, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
October 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 301182 (BOS-580-201)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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Sponsors and Collaborators

Medical Conditions

Drug Interventions

Conditions

Rare Diseases

Drug Interventions

Dietary Supplements

Sponsor/Collaborators

Locations

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