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Pemvidutide

What it is. What the evidence says.

A lab-made peptide medicine being tested by the company Altimmune. It switches on two hormone signals, GLP-1 and glucagon, with a focus on reducing fat in the liver.

Early Human EvidenceInvestigational

Predominant research setting. Clinical confidence is claim-specific.

Updated Scientific review pending
Start with the basics Regulatory status ↓
Sequence diagram and chemical structure information for Pemvidutide.
Pemvidutide Chemical Structure & Sequence · Inside Peptides Scientific Library
Compound
Pemvidutide
Human effectiveness
Phase 2 trials show liver-fat reduction and MASH resolution versus placebo; fibrosis benefit not shown at 24 weeks; no phase 3 results yet
Regulatory status
Investigational Drug
START HERE · PLAIN LANGUAGE

Pemvidutide: the basics

What is it?

A lab-made peptide medicine being tested by the company Altimmune. It switches on two hormone signals, GLP-1 and glucagon, with a focus on reducing fat in the liver.

Research paper 1 ↗Research paper 2 ↗

What do people claim it helps with?

Treating fatty liver disease, including the inflamed form called MASH, and helping with weight loss.

What has research actually shown?

Mid-stage controlled trials found big drops in liver fat and more people with MASH cleared versus placebo. Liver scarring (fibrosis) did not improve significantly at 24 weeks.

Research paper 1 ↗Research paper 2 ↗

Has this been demonstrated in people?

Phase 2 randomized trials in adults, plus earlier mouse studies, funded by the developer. A larger phase 3 trial has only just started.

Research paper 1 ↗Research paper 2 ↗

What side effects, risks and unknowns should I understand?

Side effects in trials were mostly mild or moderate, and few people stopped treatment because of them. The trials were small and short, so rarer or long-term risks are unknown.

Research paper 1 ↗Research paper 2 ↗

Is it an approved medicine?

No FDA-approved medicine contains pemvidutide. It is still being tested in clinical trials.

FDA safety information ↗

Approval here means U.S. FDA approval and applies to a particular product, formulation and use. This is a starting overview, not a complete side-effect list. Sources checked 10 October 2026; independent scientific review pending.

How is it used or studied?

Tested as a once-weekly injection in clinical trials. There is no approved product.

Different routes and formulations can have different effects. A study of one product does not validate every product with the same peptide name.

A common misunderstanding

Lower liver fat on a scan is not the same as healing liver scarring. Pemvidutide is different from survodutide and mazdutide.

What should I ask a clinician?
  • What diagnosis or goal are we trying to address, and what established options are available?
  • Was the expected benefit shown in people like me, using this exact product?
  • How could my medicines, health conditions or pregnancy plans affect the risks?
  • What monitoring is needed, and what would tell us the treatment is helping or should be stopped?
What do the research words mean?
Peptide
A short chain of amino acids, the building blocks of proteins.
Preclinical
Research in cells, tissues or animals before dependable treatment evidence in people.
Controlled trial
A study comparing a treatment with another treatment or a placebo to help separate its effects from other explanations.
Biomarker
A measurement, such as a hormone level. A change does not necessarily mean someone feels better or lives longer.
THE AVAILABLE RESEARCH

Pemvidutide Evidence & Clinical Profile

Human Clinical Evidence

Human Study Limits

Pemvidutide has been investigated in clinical contexts. Patient outcomes must be evaluated against study size, design, and control cohorts.

Preclinical & Pharmacological Data

Laboratory & In Vivo Assays

Cellular and animal disease models examine receptor binding affinities and signaling cascades, which require human confirmation.

Understand our evidence labels →

IDENTITY & STRUCTURE

What is Pemvidutide?

Pemvidutide (ALT-801) is Pemvidutide is an investigational once-weekly injectable peptide from Altimmune that activates GLP-1 and glucagon receptors. Phase 2 trials reported large reductions in liver fat and resolution of MASH in some patients, but fibrosis did not improve significantly at 24 weeks. A phase 3 MASH trial is recruiting. Aliases include: ALT-801, GLP-1/glucagon dual agonist.

Chemical sequence and molecular parameters of Pemvidutide
Primary sequence schematic · Inside Peptides Molecular Database
Chemical reference
Sequence (one-letter)
N/A
Molecular formula
N/A
Molecular weight
N/A
CAS Number
2538014-94-5
UNII Code
A35F525WBG
PubChem CID
N/A

PubChem has no compound record yet; the UNII and CAS are from FDA GSRS.

Identifiers checked against PubChem and FDA's Global Substance Registration System on 13 October 2026. FDA substance record ↗ See all names and codes in the peptide name index.

HUMAN RESEARCH

Clinical Trials & Human Cohorts

Human research can examine tolerability, symptoms or patient outcomes. The design and comparator determine what each result can establish.

Phase 2b double-blind, placebo-controlled randomized trial; 24-week analysis of a 48-week study2025

Safety and efficacy of weekly pemvidutide versus placebo for MASH (IMPACT): 24-week results [1]

n = 212Adults with biopsy-confirmed MASH and fibrosis stage F2 or F3, 83 sites in the USA and Australia

What was reported

MASH resolution without worsening fibrosis: 52%–58% with pemvidutide versus 20% with placebo.

What limits the conclusion

Did not meet its second primary endpoint: fibrosis improvement (33%–36% vs 28%) was not significantly different from placebo at 24 weeks. Funded by Altimmune.

Read primary source ↗ (external website)
Randomized, double-blind, placebo-controlled trial; 12 weeks2025

Effect of pemvidutide, a GLP-1/glucagon dual receptor agonist, on MASLD [2]

n = 94Adults with BMI 28 or higher and at least 10% liver fat on MRI; 29% had type 2 diabetes

What was reported

Liver fat fell by 46.6%–68.5% (relative) across pemvidutide groups versus 4.4% with placebo; maximal weight loss was 4.3%.

What limits the conclusion

Small, short trial using imaging rather than biopsy outcomes.

Read primary source ↗ (external website)
Double-blind 12-week extension of the randomized MASLD trial2025

Safety and efficacy of 24 weeks of pemvidutide in MASLD [3]

n = 64Completers of the 12-week trial who continued their assigned treatment

What was reported

After 24 weeks liver fat fell by 56.3%–76.4% versus 14.0% with placebo; body weight fell 6.2%.

What limits the conclusion

Only participants who finished the first phase continued, which can favour better responders. Imaging endpoints only.

Read primary source ↗ (external website)
MECHANISMS OF ACTION

How the compound may work

Mechanisms describe how Pemvidutide may affect biological processes. Laboratory findings and patient outcomes answer different questions.

01
Rationale described in human trial reports

GLP-1 plus glucagon receptor activation

GLP-1 receptor activation reduces appetite, while glucagon receptor activation acts directly on the liver to increase fat burning and reduce fat production. The pairing is intended to cut liver fat beyond what weight loss alone achieves. [2]

02
Diet-induced obese mice (animal study)

Liver effects in a mouse NASH model

In mice with diet-induced fatty liver disease, ALT-801 reduced body weight, liver fat, and markers of inflammation and fibrosis more than semaglutide or elafibranor. Mouse results may not translate to people. [4]

RESEARCH AREAS

Areas Being Studied

These research topics reflect active areas of scientific exploration, distinct from unverified commercial marketing claims.

Phase 2b trial; phase 3 recruiting

MASH and liver fibrosis

Biopsy-based MASH resolution and fibrosis outcomes. [1]

Randomized imaging trials

Fatty liver disease (MASLD)

Reduction in liver fat measured by MRI. [2]

Phase 2 trial (registered)

Obesity

A completed obesity trial is registered; peer-reviewed results were not found in PubMed at the time of review. [6]

Phase 2 trial (registered)

Alcohol use disorder

A completed trial in people with alcohol use disorder and obesity or overweight; results not yet published. [8]

AT A GLANCE

Compare the study designs.

Overview of Key Pemvidutide Studies: clinical and preclinical records
Study Design / sample Outcome type Key limitation
IMPACT: MASH with F2–F3 fibrosis · 2025 [1] Phase 2b double-blind, placebo-controlled randomized trial; 24-week analysis of a 48-week study
n = 212		 Clinical endpoint evaluation Did not meet its second primary endpoint: fibrosis improvement (33%–36% vs 28%) was not significantly different from placebo at 24 weeks. Funded by Altimmune.
MASLD: 12-week liver fat · 2025 [2] Randomized, double-blind, placebo-controlled trial; 12 weeks
n = 94		 Clinical endpoint evaluation Small, short trial using imaging rather than biopsy outcomes.
MASLD: 24-week extension · 2025 [3] Double-blind 12-week extension of the randomized MASLD trial
n = 64		 Clinical endpoint evaluation Only participants who finished the first phase continued, which can favour better responders. Imaging endpoints only.
FDA & SAFETY

Regulatory Status & Clinical Safety

Regulatory Classification

United States, checked 11 October 2026: not FDA-approved; no pemvidutide product appears in Drugs@FDA or DailyMed. It is in phase 3 development for MASH. Note that the code "ALT-801" was also used for an unrelated Altor BioScience cancer drug in older trial records.

Safety Realities & Impurities

Safety depends on the molecule, formulation, route and evidence. A laboratory purity measurement alone cannot establish safety for human use.

REGISTRY CHECK

Clinical Trials Registry Records

Official registry records from ClinicalTrials.gov. Study registration does not imply government endorsement or guaranteed efficacy.

Phase 2Completed

IMPACT TRIAL: Efficacy and Safety of Pemvidutide in Subjects With Nonalcoholic Steatohepatitis (NASH) [5]

Planned enrollment
212 (actual enrollment)
Posted results
Pending in registry
Sponsor
Altimmune, Inc.
Last updated
2026-05-18
NCT05989711 · Open registry ↗ (external website)
Phase 3Recruiting

Phase 3 Study of the Efficacy, Safety, and Clinical Outcomes of Pemvidutide in MASH (PERFORMA) [7]

Planned enrollment
1800 (estimated enrollment)
Posted results
Pending in registry
Sponsor
Altimmune, Inc.
Last updated
2026-09-23
NCT07795164 · Open registry ↗ (external website)
Phase 2Completed

RECLAIM STUDY: Phase 2 Study of the Efficacy and Safety of Pemvidutide in the Treatment of Alcohol Use Disorder (AUD) in Subjects With Obesity or Overweight [8]

Planned enrollment
100 (actual enrollment)
Posted results
Pending in registry
Sponsor
Altimmune, Inc.
Last updated
2026-07-31
NCT06987513 · Open registry ↗ (external website)
COMPETITIVE SPORT

WADA & Anti-Doping Regulations

Not Prohibited

WADA Anti-Doping Status

Pemvidutide is not prohibited under current World Anti-Doping Agency (WADA) regulations. However, athletes must ensure unregulated preparations or unverified vendor products do not violate Section S0 (Non-approved substances). Last verified: October 2026.

SELECTED MILESTONES

Research Timeline

  1. 2022

    Mouse NASH study

    ALT-801 reduces liver fat and disease markers in diet-induced obese mice. [4]

  2. 2025

    MASLD imaging trials published

    12-week and 24-week trials report liver-fat reductions. [2]

  3. 2025

    IMPACT 24-week results

    Phase 2b trial meets MASH-resolution endpoint but not fibrosis endpoint. [1]

  4. 2026

    Phase 3 begins

    PERFORMA phase 3 MASH trial is recruiting; pemvidutide is not FDA-approved. [7]

OPEN QUESTIONS

What Researchers Still Don't Know

Long-term safety profiles

Multi-year observational data in broader heterogeneous cohorts remains uncharacterized.

Optimal dose-response thresholds

Comparative trials optimizing minimal effective exposure versus adverse event rates.

Formulation bioavailability

Differences between oral, subcutaneous, and modified peptide delivery vehicles.

TRACEABLE SOURCES

References

Primary sources verified against PubMed / NLM and regulatory databases.

  1. Phase 2b RCT

    Safety and efficacy of weekly pemvidutide versus placebo for metabolic dysfunction-associated steatohepatitis (IMPACT): 24-week results from a multicentre, randomised, double-blind, phase 2b study ↗ (external website)

    Noureddin M et al. · Lancet · 2025 DOI: 10.1016/S0140-6736(25)02114-2 ↗ (external website)
  2. Randomized controlled trial

    Effect of pemvidutide, a GLP-1/glucagon dual receptor agonist, on MASLD: A randomized, double-blind, placebo-controlled study ↗ (external website)

    Harrison SA et al. · J Hepatol · 2025 DOI: 10.1016/j.jhep.2024.07.006 ↗ (external website)
  3. Randomized trial extension

    Safety and efficacy of 24 weeks of pemvidutide in metabolic dysfunction-associated steatotic liver disease: A randomized, controlled clinical trial ↗ (external website)

    Browne SK et al. · JHEP Rep · 2025 DOI: 10.1016/j.jhepr.2025.101483 ↗ (external website)
  4. Animal study

    Effects of ALT-801, a GLP-1 and glucagon receptor dual agonist, in a translational mouse model of non-alcoholic steatohepatitis ↗ (external website)

    Nestor JJ et al. · Sci Rep · 2022 DOI: 10.1038/s41598-022-10577-2 ↗ (external website)
  5. Registry Record

    IMPACT TRIAL: Efficacy and Safety of Pemvidutide in Subjects With Nonalcoholic Steatohepatitis (NASH) ↗ (external website)

    ClinicalTrials.gov · 2026
  6. Registry Record

    Efficacy and Safety of ALT-801 in the Treatment of Obesity ↗ (external website)

    ClinicalTrials.gov · 2023
  7. Registry Record

    Phase 3 Study of the Efficacy, Safety, and Clinical Outcomes of Pemvidutide in MASH (PERFORMA) ↗ (external website)

    ClinicalTrials.gov · 2026
  8. Registry Record

    RECLAIM STUDY: Phase 2 Study of the Efficacy and Safety of Pemvidutide in the Treatment of Alcohol Use Disorder (AUD) in Subjects With Obesity or Overweight ↗ (external website)

    ClinicalTrials.gov · 2026