Pemvidutide

Pemvidutide is a unimolecular peptide engineered with a balanced, roughly 1:1 potency ratio between GLP-1 and glucagon receptor agonism, developed by Altimmune. Adding glucagon receptor activity is a deliberate mechanistic choice distinct from GLP-1/GIP combination drugs: glucagon receptor signaling acts directly on hepatocytes to promote fatty-acid oxidation and inhibit lipogenesis, and is associated with increased energy expenditure — effects aimed specifically at reducing liver fat, not just body weight.

That rationale underlies pemvidutide's dual development strategy: it is being studied in Phase 2b for obesity/overweight (MOMENTUM trial) and separately for MASH/MASLD, where it holds FDA Breakthrough Therapy designation and is progressing from Phase 2b (IMPACT trial) toward a planned Phase 3 (PERFORMA). It has also been explored earlier-stage for alcohol use disorder and alcohol-associated liver disease, though that indication is less independently verified.

In the 48-week MOMENTUM obesity trial, the 2.4 mg dose produced 15.6% mean weight loss versus 2.2% on placebo, with more than 30% of participants losing at least 20% of body weight — and roughly 78% of the weight lost was fat mass, suggesting relative preservation of lean mass. In the 48-week IMPACT MASH trial, 27.8–32.4% of treated participants (versus 3.2% on placebo) achieved both a meaningful reduction in a liver fibrosis score and a reduction in liver stiffness.

// DUAL GLP-1/GLUCAGON RECEPTOR AGONISM

Pemvidutide activates the GLP-1 receptor for appetite suppression and the glucagon receptor for direct hepatic effects, engineered with a roughly balanced 1:1 potency ratio between the two — a deliberate design distinct from GLP-1/GIP combination drugs like tirzepatide.

// HEPATIC FAT OXIDATION

Glucagon receptor activation on hepatocytes stimulates fatty-acid oxidation and suppresses lipogenesis, directly reducing liver fat content — the specific mechanistic basis for pursuing MASH/MASLD as an indication distinct from obesity alone.

// ENERGY EXPENDITURE

Glucagon signaling is separately associated with increased energy expenditure, a mechanism proposed to complement GLP-1-driven appetite suppression rather than duplicate it, though the precise magnitude of this contribution in humans was not detailed in a primary source reviewed for this entry.

MOMENTUM (Phase 2, obesity, 48 weeks): 2.4 mg dose produced 15.6% mean weight loss vs. 2.2% placebo; more than 30% of participants lost at least 20% body weight; 1.2 mg and 1.8 mg doses produced 10.3% and 11.2% weight loss respectively. Roughly 78% of weight lost was fat mass.

IMPACT (Phase 2b, MASH, 48 weeks, 212 patients with biopsy-confirmed F2/F3 fibrosis): at week 24, 1.2 mg and 1.8 mg doses produced 4.5% and 7.5% weight loss vs. 0.2% placebo. At week 48, 27.8–32.4% of treated participants (vs. 3.2% placebo) achieved both a ≥0.5 reduction in Enhanced Liver Fibrosis score and a ≥30% reduction in liver stiffness measurement; the 1.8 mg dose also reduced triglycerides by 23.7% and total cholesterol by 15.4%.

PERFORMA (planned Phase 3, MASH): planned to start in the second half of 2026, aligned with FDA/EMA feedback; pemvidutide holds FDA Breakthrough Therapy designation for MASH. A separately named Phase 3 obesity trial was not found in sources reviewed.

Safety: gastrointestinal adverse events (nausea ~40–55%, diarrhea ~20–25%, constipation ~15–20%, vomiting ~10–15% at the 2.4 mg MOMENTUM dose) were dose-dependent and mostly mild-to-moderate, diminishing after roughly week 16. No cardiac safety imbalances were reported in trials reviewed.