Altimmune Reports Positive 48-Week Phase 2b Results for Pemvidutide in MASH Patients

Altimmune has announced new 48-week results from its IMPACT Phase 2b trial evaluating pemvidutide, an investigational dual glucagon/GLP-1 receptor agonist, in patients with metabolic dysfunction-associated steatohepatitis (MASH).

The latest findings show that pemvidutide not only improved liver-related measures but also reduced elevated lipid levels and improved several cardiometabolic risk factors. These results were presented for the first time at the European Association for the Study of the Liver (EASL) Congress 2026 in Barcelona, Spain.

The data add to the growing evidence that pemvidutide may help address both liver disease and the metabolic conditions that often drive it.

Significant Improvements in Lipids and Metabolic Health

The 48-week analysis showed meaningful reductions in several key markers associated with cardiovascular and metabolic disease.

Patients treated with pemvidutide experienced:

• Lower triglyceride levels

• Reduced total cholesterol

• Weight loss

• Reduced waist circumference

• Improved blood pressure

These improvements are particularly important because people with MASH often face a higher risk of cardiovascular disease, which remains one of the leading causes of death in this patient population.

According to Dr. Mazen Noureddin, principal investigator of the IMPACT trial and Professor of Medicine at Houston Methodist Hospital, the results demonstrate meaningful reductions in liver fat and fibrosis biomarkers while also improving important metabolic risk factors.

He noted that therapies capable of addressing both liver disease and its underlying metabolic causes are urgently needed to improve long-term patient outcomes.

Safety Profile Remains Favorable at 48 Weeks

The study also confirmed that pemvidutide maintained a favorable safety profile through 48 weeks of treatment.

Only about 1% of patients receiving pemvidutide discontinued treatment due to adverse events.

Most side effects were mild to moderate in severity. Gastrointestinal side effects were generally observed during the first eight weeks of treatment and were mostly manageable.

Importantly, researchers found no imbalance in cardiac adverse events between patients receiving pemvidutide and those receiving placebo.

These findings suggest that pemvidutide continues to demonstrate good tolerability even without dose titration.

Earlier Results Showed Strong Fibrosis Improvements

The newly reported metabolic data build upon previously announced IMPACT Phase 2b findings.

Earlier analyses showed that patients receiving pemvidutide achieved significantly better liver fibrosis outcomes compared to placebo.

The proportion of patients achieving both a reduction in Enhanced Liver Fibrosis (ELF) score and a reduction in Liver Stiffness Measurement (LSM) at Week 48 was:

• 3.2% in the placebo group

• 27.8% in the 1.2 mg pemvidutide group

• 32.4% in the 1.8 mg pemvidutide group

These results suggest that pemvidutide may provide meaningful benefits in slowing or reversing disease progression in MASH patients.

Why Pemvidutide Is Different

Pemvidutide is a novel peptide therapy designed with a balanced 1:1 ratio of glucagon and GLP-1 receptor activity.

This dual mechanism is intended to provide benefits across multiple disease pathways.

Activation of glucagon receptors directly affects the liver by helping reduce:

• Liver fat accumulation

• Inflammation

• Fibrosis

At the same time, activation of GLP-1 receptors helps regulate metabolism through:

• Appetite suppression

• Weight reduction

• Improved metabolic control

According to Altimmune's Chief Medical Officer, Christophe Arbet-Engels, the consistent findings across multiple analyses continue to strengthen confidence in pemvidutide's unique mechanism of action and its potential to address major unmet needs in MASH treatment.

Understanding the IMPACT Phase 2b Trial

The IMPACT study was a randomized, placebo-controlled, double-blind Phase 2b trial involving 212 participants.

All participants had biopsy-confirmed MASH with fibrosis stages F2 or F3. Both diabetic and non-diabetic patients were included in the study.

Participants were randomly assigned to receive:

• Pemvidutide 1.2 mg weekly

• Pemvidutide 1.8 mg weekly

• Placebo

Treatment continued for 48 weeks.

The primary efficacy endpoints evaluated MASH resolution without worsening fibrosis or fibrosis improvement without worsening MASH.

Secondary endpoints included weight loss and several non-invasive measures of liver fibrosis.

Regulatory Progress and Upcoming Clinical Trials

Pemvidutide has already received significant regulatory recognition from the U.S. Food and Drug Administration.

The therapy has been granted:

• Fast Track Designation for MASH

• Fast Track Designation for Alcohol Use Disorder (AUD)

• Breakthrough Therapy Designation for MASH

Altimmune is also advancing pemvidutide across multiple liver-related indications.

The RECLAIM Phase 2 study in Alcohol Use Disorder completed enrollment in November 2025, with topline results expected in the third quarter of 2026.

The RESTORE trial in Alcohol-Associated Liver Disease began in July 2025 and is expected to complete enrollment during the third quarter of 2026.

Most importantly, Altimmune plans to launch the PERFORMA Phase 3 trial for MASH during the second half of 2026.

About Altimmune

Altimmune is a late clinical-stage biopharmaceutical company focused on developing treatments for serious liver diseases.

The company's lead drug candidate, pemvidutide, is being developed for:

• Metabolic dysfunction-associated steatohepatitis (MASH)

• Alcohol Use Disorder (AUD)

• Alcohol-Associated Liver Disease (ALD)

Through its unique balanced dual agonist approach, Altimmune aims to address both liver disease and the metabolic conditions that contribute to disease progression.

Conclusion

The latest 48-week IMPACT Phase 2b data provide further evidence that pemvidutide may offer benefits beyond liver health alone. By reducing lipids, improving weight and blood pressure, and demonstrating positive effects on fibrosis markers, the therapy continues to show promise as a potential treatment for MASH.

With Phase 3 development expected to begin later this year, pemvidutide is emerging as one of the more closely watched investigational therapies in the growing MASH treatment landscape.