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Efimosfermin

Phase 2

Metabolic Dysfunction-Associated Steatohepatitis | Small molecule | Metabolic |GSK plc|Last Updated: Jul 8, 2026

Success Probability

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Trial Design

RandomizedDouble-BlindPLACEBO_CONTROLLED
Total Trials1
Total Enrollment42

FDA Designations

No designations recorded

Clinical trial landscape

Efimosfermin · 2 trials · 3 indications

Phase 2 2
NCT06920043A Study of Efimosfermin Alfa in Participants With Biopsy-confirmed Cirrhosis (Compensated) Due to MASHMetabolic Dysfunction-Associated Steatohepatitis
RECRUITING42 Analytics
NCT04880031A Study of BOS-580 in Obese Subjects at Risk for, or With Biopsy-confirmed, Nonalcoholic Steatohepatitis (NASH) With an ExtensionNonalcoholic Steatohepatitis (NASH)
COMPLETED231 Analytics
PHASE2RECRUITING
A Study of Efimosfermin Alfa in Participants With Biopsy-confirmed Cirrhosis (Compensated) Due to MASH
Metabolic Dysfunction-Associated SteatohepatitisUnlock trial analytics
PHASE2COMPLETED
A Study of BOS-580 in Obese Subjects at Risk for, or With Biopsy-confirmed, Nonalcoholic Steatohepatitis (NASH) With an Extension
Nonalcoholic Steatohepatitis (NASH)Unlock trial analytics

Study Endpoints

Primary Endpoints

Number of participants with treatment emergent adverse events (TEAEs)
From Day 1 to 100 weeks

To assess the effects of efimosfermin on safety and tolerability.

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)
Until End of study/Early Termination (Day 393)

The effects of Efimosfermin on safety and tolerability will be assessed.

Part A, Part B, Part C, and Part D: Changes from Baseline in systolic and diastolic blood pressure (BP)
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.

Part A, Part B, Part C, and Part D: Changes from Baseline in heart rate
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.

Part A, Part B, Part C, and Part D: Number of participants with Grade 3 and Grade 4 laboratory abnormalities
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.

Secondary Endpoints

Serum concentrations of efimosfermin
Up to Week 21
Maximum serum drug concentration (Cmax) of efimosfermin
Up to Week 21
Area under the serum concentration-time curve (AUC) of efimosfermin
Up to Week 21
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Study Design & Arms

AllocationRANDOMIZED
MaskingDOUBLE
ModelPARALLEL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
Efimosfermin (Dose 1)EXPERIMENTALParticipants will receive efimosfermin (Dose 1) once every 4 weeks (Q4W).
Efimosfermin (Dose 2)EXPERIMENTALParticipants will receive efimosfermin (Dose 2) Q4W.
PlaceboPLACEBO_COMPARATORParticipants will receive placebo Q4W.
Cohort A1: Efimosfermin Dose 1 or placebo (PBO)EXPERIMENTAL -
Cohort A2: Efimosfermin Dose 2 or PBOEXPERIMENTAL -
Cohort A3: Efimosfermin Dose 3 or PBOEXPERIMENTAL -
Cohort A4: Efimosfermin Dose 4 or PBOEXPERIMENTAL -
Cohort A5: Efimosfermin Dose 5 or PBOEXPERIMENTAL -
Part B: Efimosfermin Dose 1 or PBOEXPERIMENTAL -
Part C: Efimosfermin Dose 1EXPERIMENTAL -
Part D: Efimosfermin Dose 6 or PBOEXPERIMENTAL -
Part D: Efimosfermin Dose 1 or PBOEXPERIMENTAL -

Interventions

NameTypeDescription
EfimosferminDRUGEfimosfermin will be administered as a subcutaneous injection.
PlaceboDRUGPlacebo will be administered as a subcutaneous injection.
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Eligibility Criteria

Age Range18 Years to 75 Years
SexALL
Healthy VolunteersNo
Study Sites30

Inclusion Criteria: * Ability to understand and sign a written informed consent form (ICF) * Age 18 through 75 years at enrollment * History or presence of 2 or more of the 5 components of metabolic syndrome * Liver biopsy confirmation of MASH consistent with stage F4 fibrosis * Other inclusion cri...

Countries:United States
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Recent Changes (Last 90 Days)

MEDIUMAug 8, 2026NCT04880031TRIAL_REMOVED: changed
MEDIUMAug 8, 2026NCT04880031TRIAL_REMOVED: changed
MEDIUMAug 8, 2026NCT04880031TRIAL_REMOVED: changed
MEDIUMAug 8, 2026NCT04880031TRIAL_REMOVED: changed

Frequently asked questions about Efimosfermin

What is Efimosfermin used for?

Efimosfermin is an investigational small molecule being developed for Nonalcoholic Steatohepatitis (NASH) and Metabolic Dysfunction-Associated Steatohepatitis (MASH). It is being studied in patients with biopsy-confirmed NASH or MASH, including those with compensated cirrhosis due to MASH.

Who makes Efimosfermin?

Efimosfermin is being developed by GSK plc, which trades under the ticker GSK. The company is conducting clinical trials of the drug in the United States for Nonalcoholic Steatohepatitis (NASH) and Metabolic Dysfunction-Associated Steatohepatitis (MASH).

What phase is Efimosfermin in?

Efimosfermin is in Phase 2 clinical development. It is an investigational drug and has not been approved by regulatory authorities. Two Phase 2 trials are listed: one completed study and one actively recruiting study in patients with MASH-related cirrhosis.

What clinical trials is Efimosfermin in?

Efimosfermin is being studied in two Phase 2 trials. NCT04880031, a completed study in obese subjects at risk for or with biopsy-confirmed NASH, enrolled 231 participants. NCT06920043, currently recruiting, is studying the drug in 42 participants with biopsy-confirmed compensated cirrhosis due to MASH.

Is Efimosfermin the same as BOS-580?

Efimosfermin is the same drug as BOS-580. The completed Phase 2 trial NCT04880031 was titled 'A Study of BOS-580 in Obese Subjects at Risk for, or With Biopsy-confirmed, Nonalcoholic Steatohepatitis (NASH) With an Extension,' and the drug is now referred to as Efimosfermin in later trials.