Pemvidutide (ALT-801)

Pemvidutide is a real, investigational balanced (1:1) GLP-1/glucagon dual receptor agonist peptide from Altimmune, in development across three separate indications — obesity, metabolic dysfunction-associated steatohepatitis (MASH), and alcohol use disorder (AUD). It already has completed, published Phase 2 trials in the first two, an FDA Breakthrough Therapy designation for MASH, and a positive Phase 2 topline readout in AUD as of July 2026 — but it is not approved anywhere, and its most recent, most striking results are still company-reported topline figures rather than peer-reviewed publications.

What it is, and the mechanism

Pemvidutide (Altimmune's internal code ALT-801) is a synthetic peptide engineered to activate the GLP-1 receptor and the glucagon receptor in a deliberately balanced, roughly 1:1 ratio. That's a mechanistic cousin of this site's survodutide page (also a GLP-1/glucagon dual agonist, from Boehringer Ingelheim and Zealand Pharma) and mazdutide page (the same receptor pair, already approved in China) — but pemvidutide is a chemically distinct molecule from an independent company. It carries a proprietary "EuPort" domain that prolongs its serum half-life and slows its absorption, which Altimmune says allows once-weekly dosing without the dose-escalation schedule most drugs in this class need to manage nausea. The rationale for pairing glucagon-receptor agonism with GLP-1 is the same one survodutide's page describes: GLP-1 suppresses appetite, while glucagon-receptor activity is intended to increase energy expenditure and act directly on the liver to reduce fat — the basis for Altimmune's parallel development of pemvidutide in obesity and in MASH.

The published Phase 2 evidence in obesity and liver disease

In a Phase 2 obesity trial (MOMENTUM) presented at the American Diabetes Association's 84th Scientific Sessions in June 2024, 391 adults with overweight or obesity and at least one weight-related comorbidity were randomized to pemvidutide (1.2mg, 1.8mg, or 2.4mg weekly) or placebo. At 48 weeks, mean weight loss was 10.3%, 11.2%, and 15.6% across the three doses, versus 2.2% with placebo; body-composition analysis found roughly 78% of the weight lost was fat rather than lean mass. In a separate, published 12-week Phase 2 trial in metabolic dysfunction-associated steatotic liver disease (MASLD) (Harrison SA, Browne SK, Suschak JJ, et al., J Hepatol 2024, PMID 39002641), liver fat content fell by 46.6%, 68.5%, and 57.1% across the three doses, versus 4.4% with placebo.

Pemvidutide then moved into IMPACT, a Phase 2b trial in 212 patients with biopsy-confirmed MASH and stage F2-F3 fibrosis. Published 24-week results (Noureddin M, Harrison SA, Loomba R, et al., Lancet 2025) found MASH resolution without worsening fibrosis in 58% and 52% of patients on the 1.2mg and 1.8mg doses, versus 20% on placebo, a statistically significant difference; a numerical trend toward fibrosis improvement did not reach statistical significance at this early timepoint. Altimmune later reported 48-week IMPACT topline results (December 2025, company-reported): liver fat down 45.2% and 54.7% versus 8.2% with placebo, ALT reductions of roughly 38 IU/L versus 10.3, and continued weight loss of 4.5% and 7.5% versus 0.2%, with low treatment-related discontinuation. The FDA has granted pemvidutide Fast Track designation for both MASH and AUD, and Breakthrough Therapy designation for MASH; a registrational Phase 3 trial in MASH (PERFORMA) was actively enrolling as of this review.

A third, unrelated indication: alcohol use disorder

Unlike any other GLP-1-family peptide covered on this site, Altimmune is also developing pemvidutide for alcohol use disorder (AUD) and alcohol-associated liver disease — following a broader, still-emerging research interest in whether GLP-1-pathway drugs affect addictive behavior generally, not just appetite. In a Phase 2 trial (RECLAIM) in roughly 100 patients with moderate-to-severe AUD, Altimmune announced positive topline results on 28 July 2026: the 2.4mg dose produced a statistically significant, clinically meaningful reduction in heavy drinking days (the trial's primary endpoint), and also met two secondary endpoints the FDA recognizes as registrational in this indication — a two-level reduction in WHO risk drinking level, and achievement of zero heavy drinking days. The company described tolerability in the trial as generally favorable.

What's still unresolved

Pemvidutide is not approved anywhere, and no regulatory filing appears to have been submitted for any of its three indications as of this review. The 48-week IMPACT liver-disease figures and the RECLAIM alcohol-use-disorder results are both company-reported topline data rather than full peer-reviewed manuscripts — real and specific, but not yet independently scrutinized the way the published 24-week IMPACT and MOMENTUM trial data have been. Longer-term safety in a broader, more diverse population, and how the three development programs interact commercially and regulatorily, are open questions to watch for in the full trial publications and in PERFORMA's eventual Phase 3 readout.