Pemvidutide is an engineered peptide with GLP-1 and glucagon receptor activity, studied for metabolic liver disease, obesity and more recently alcohol-related conditions. Its most developed liver evidence moves from magnetic-resonance measurements of liver fat to biopsy-based assessment of MASH, the inflammatory form of metabolic fatty liver disease. The published IMPACT analysis found more MASH resolution at 24 weeks, while its other primary endpoint, fibrosis improvement, was statistically inconclusive. Later sponsor reports describe noninvasive marker improvements and the start of phase 3. Pemvidutide remains investigational as of October 13, 2026. Harrison et al. (2025), Noureddin et al. (2025), Altimmune (2026).
Overview
Molecular profile
Pemvidutide carries the development code ALT-801 in the metabolic programme. Nestor and colleagues selected it from a series of peptides carrying a glycolipid surfactant modification, which combines a fat-like portion with a sugar-related portion. Their experiments linked prolonged duration to high serum albumin binding. Altimmune's EuPort description records the same general hydrophobic and hydrophilic design principle. This joins exposure engineering to the peptide's two receptor activities. Nestor et al. (2021), Altimmune (2026 Form 10-K).
Uses and research areas
The liver trials distinguish metabolic dysfunction-associated steatotic liver disease, or MASLD, from MASH. MASLD involves excessive liver fat in a metabolic context. MASH adds inflammatory injury, which can lead to fibrosis and eventually advanced liver disease. The difference determines what a study must measure: liver-fat imaging assesses steatosis, whereas biopsy can assess inflammation, cell injury and fibrosis stage.
MOMENTUM studied weight management in adults without diabetes. IMPACT studied biopsy-confirmed MASH with moderate or advanced noncirrhotic fibrosis. The PERFORMA phase 3 programme advances that liver indication. Altimmune is also studying alcohol use disorder and alcohol-associated liver disease in separate programmes; those populations and endpoints require their own evidence. MOMENTUM investigators (2024), Noureddin et al. (2025), Altimmune (2026).
Mechanism of action
GLP-1 receptor activation participates in appetite regulation and glucose-dependent insulin secretion. Glucagon receptor activation alters hepatic fuel handling, including glucose production and lipid metabolism. Combining these activities provides a rationale for studying a treatment that affects body weight and liver fat together.
The term balanced dual agonism describes relative receptor activity in a particular experimental system. In the discovery work, albumin in the assay influenced the apparent potency because it bound the modified peptides. Nestor and colleagues compared assay conditions to examine that effect. Weight change can reduce metabolic pressure on the liver, and receptor-mediated hepatic effects may contribute as well; human trials measure the resulting combined response. Nestor et al. (2021), Harrison et al. (2025).
Pharmacokinetics
The exposure-extending modification helps distinguish pemvidutide from rapidly cleared native hormones. Its clinical programme has used subcutaneous administration, but a reliable concentration–time illustration requires more than the treatment interval: it needs the measured analyte, a defined population and validated numerical observations or an elimination estimate. Altimmune (2026 Form 10-K), Noureddin et al. (2025).
The original development report described a 52-hour half-life in mini-pigs for selected compound 17, ALT-801. That animal measurement helps explain candidate selection, while human pharmacokinetics require the clinical formulation, sampling and population to be specified separately. Nestor et al. (2021).
The primary material verified for this review does not provide a sufficiently documented human half-life or numerical plasma concentration series for a graph. Liver-fat and body-weight changes occur on a different timescale and cannot be used to reconstruct circulating peptide exposure.
Research findings
Liver-fat imaging and the selected extension population
Harrison and colleagues randomised and treated 94 adults with BMI at least 28 and liver fat at least 10% by MRI-PDFF, a magnetic-resonance measure of the proportion of liver signal attributable to fat. Twenty-nine percent had type 2 diabetes. At 12 weeks, relative liver-fat reductions were 46.6%, 68.5% and 57.1% across three active groups, versus 4.4% with placebo. A relative reduction describes change from the initial amount of liver fat, rather than a fall of the same number of percentage points in absolute fat content. Harrison et al. (2025).
Browne and colleagues reported a further 12 weeks of treatment in selected parent-trial completers. The extension included 64 eligible participants, drawn from 83 completers of the 94-person treated parent population; 66 had consented. At total week 24, relative liver-fat reductions were 56.3%, 75.2% and 76.4% versus 14.0% with placebo. Selection into the extension matters because it describes people able and eligible to continue, rather than a second independent 94-person randomised trial. Browne et al. (2025).
Weight reduction in MOMENTUM
The 48-week MOMENTUM obesity trial enrolled 391 adults without diabetes. Its conference report described mean weight reductions of 10.3%, 11.2% and 15.6% in the three active groups versus 2.2% with placebo. These results provide a weight-management finding, while the conference source offers less methodological and safety detail than a full trial publication. MOMENTUM investigators (2024).
Biopsy outcomes at 24 weeks in IMPACT
IMPACT randomised 212 adults with biopsy-confirmed MASH and fibrosis stages F2 or F3. Its two primary endpoints were MASH resolution without worsening fibrosis and at least one-stage fibrosis improvement without worsening MASH, analysed in the intention-to-treat population at 24 weeks. MASH resolution occurred in 24 of 41 participants (58%) and 45 of 85 (52%) in the active groups, versus 18 of 86 (20%) with placebo. Both comparisons were statistically significant. Noureddin et al. (2025).
Fibrosis improvement occurred in 33% and 36% versus 28% with placebo. The comparisons were inconclusive (P=0.59 and P=0.27). The trial therefore supports a change in MASH activity at this time point while leaving the size and certainty of the fibrosis effect unresolved.
Later markers and the move into phase 3
Altimmune's 48-week IMPACT report described improvements in the Enhanced Liver Fibrosis score, a blood-based marker panel, and liver stiffness measurement. By design, this later assessment did not include a further histological readout. Those measurements add information about disease activity and possible fibrosis-related change, while the unresolved 24-week biopsy endpoint retains its own meaning. Altimmune (December 2025).
The sponsor announced initiation of the PERFORMA phase 3 MASH trial in August 2026 and currently describes it as actively enrolling. That is a development milestone, with efficacy and clinical-event outcomes still awaiting study. Altimmune (2026), Altimmune release archive (August 2026).
Safety and tolerability
The IMPACT 24-week report found adverse events in 78% and 81% of participants in the active groups versus 67% with placebo, with most classified as mild or moderate. Adverse-event discontinuations occurred in none of 41 participants in the lower active group, one of 85 in the other active group and two of 86 with placebo. Noureddin et al. (2025).
The weight-management trial supplies a different tolerability picture. Altimmune's MOMENTUM report described study-drug-related discontinuation in 4.1%, 16.2% and 15.5% across active groups versus 2.1% with placebo, with most active-group adverse-event discontinuations occurring early. The population, assignments and treatment context differed from IMPACT, so the low liver-trial withdrawal rate cannot stand in for the obesity-trial experience. Altimmune (2023).
Pemvidutide remains an investigational medicine. The current phase 3 programme is designed to resolve larger and longer-term questions about efficacy, fibrosis and clinical outcomes, while uncommon harms also require greater exposure and follow-up than the early trials provide. Altimmune (2026), Altimmune (2026).
What the research means
The liver-fat studies and IMPACT form a useful progression of measurements. Imaging first demonstrated substantial reduction in steatosis; biopsy then showed improved MASH activity in a population with F2–F3 fibrosis. Fibrosis itself responded less conclusively at the 24-week primary analysis, which is consequential because scarring drives much of the risk of advanced liver disease.
Later noninvasive markers help follow the response over time, but they do not replace the biopsy endpoint with a new positive result. PERFORMA can test whether the early activity response develops into sustained histological and clinical benefits. The weight programme and alcohol-related studies extend the research questions while retaining their own populations and evidence sources.
FAQs
How do liver-fat and fibrosis measurements differ?
MRI-PDFF measures fat. Fibrosis is scar tissue and needs a separate assessment. The initial fat reductions and later biopsy findings answer different disease questions.
What did IMPACT establish at 24 weeks?
IMPACT compared pemvidutide with placebo in adults whose liver biopsies showed MASH and moderate or advanced scarring. At 24 weeks, more treated participants had resolution of inflammatory liver injury without worse scarring. The separate comparison of improvement in scarring was uncertain. Improving MASH activity and reducing established scar tissue were different outcomes.
Do the 48-week markers resolve the biopsy endpoint?
The later sponsor report measured noninvasive markers without a new biopsy readout. Those measurements add follow-up information while the original histological comparison retains its conclusion.
Why do withdrawals differ between MOMENTUM and IMPACT?
MOMENTUM studied obesity without diabetes; IMPACT studied biopsy-confirmed MASH with F2–F3 fibrosis. Different populations and assignments give each trial its own tolerability context.
Comparisons and related reading
Survodutide supplies another biopsy-based glucagon/GLP-1 programme, while mazdutide provides an example with China approvals for metabolic indications. Semaglutide and retatrutide help explain selective GLP-1 and triple-receptor approaches. Their trial results must remain attached to their own molecules and populations.
References
The initial MASLD trial quantifies relative liver-fat reduction using MRI-PDFF.
The extension follows selected parent-trial completers to 24 weeks and retains its selection denominators.
The MOMENTUM conference abstract supplies the 48-week weight result in its limited report format.
The IMPACT biopsy study found more resolution of MASH with pemvidutide than with placebo at 24 weeks. Its separate comparison of improvement in liver scarring remained uncertain.
- Nestor JJ, Zhang X, Jaw-Tsai S, Parkes DG, Becker CK (2021). Design and characterization of a surfactant-conjugated, long-acting, balanced GLP-1/glucagon receptor dual agonist. Peptide Science 113(5):e24221. DOI: 10.1002/pep2.24221. · onlinelibrary.wiley.com
The molecular report identifies ALT-801 and connects modification, albumin binding and preclinical persistence.
The filing documents pemvidutide identity, EuPort context and programme status at the reporting date.
The later report describes noninvasive markers without a new biopsy readout.
The sponsor supplies obesity-trial withdrawal figures.
The announcement establishes phase 3 initiation.
The pipeline identifies active PERFORMA enrolment and separate alcohol-related programmes.
The manufacturer identifies the medicine as investigational.
Glossary
- MASLD
- Metabolic dysfunction-associated steatotic liver disease, involving liver fat in a metabolic context.
- MASH
- Metabolic dysfunction-associated steatohepatitis, involving liver fat and inflammatory injury.
- MRI-PDFF
- Magnetic resonance imaging proton-density fat fraction, measuring tissue fat content.
- Fibrosis
- Scar tissue accumulated with sustained injury.
- F2–F3
- Moderate to advanced noncirrhotic fibrosis stages used in IMPACT.
- ELF
- Enhanced Liver Fibrosis score, a blood-based marker panel.
- Intention to treat
- Analysis by assigned treatment group, with subsequent events handled by the study’s stated methods.
- Glycolipid
- A group containing lipid-like and sugar-related portions.