Altimmune Receives FDA’s Breakthrough Therapy Designation For Its Liver Disease Drug

The FDA decision was based on 24-week data from the IMPACT Phase 2b trial, showing considerable MASH resolution without worsening fibrosis.

• The drug, a 1:1 glucagon/GLP-1 dual-receptor agonist, targets patients with metabolic dysfunction-associated steatohepatitis (MASH).
• Altimmune shared 48-week topline results in December 2025, indicating that continued pemvidutide treatment improved non-invasive tests.
• The Phase-3 trial will test multiple pemvidutide doses over a 52-week treatment period.

Altimmune, Inc. (ALT) announced on Monday that the U.S. Food and Drug Administration granted Breakthrough Therapy Designation (BTD) for its drug pemvidutide.

The drug, a 1:1 glucagon/GLP-1 dual receptor agonist, targets patients suffering from metabolic dysfunction-associated steatohepatitis (MASH), a serious liver condition with limited treatment options.

How The Recognition Helps

The designation is intended to boost the development and review of drugs that address serious or life-threatening illnesses and demonstrate early evidence of clinical benefit. 

The FDA decision was based on 24-week data from the IMPACT Phase 2b trial, showing considerable MASH resolution without worsening fibrosis, along with improvements in liver fat and non-invasive fibrosis markers.

Altimmune stock traded over 14% higher in Monday’s premarket. However, on Stocktwits, retail sentiment around the stock remained in ‘bearish’ territory while message volume shifted to ‘extremely low’ from ‘low’ levels in 24 hours. 

Clinical Progress

Altimmune shared 48-week topline results in December 2025, indicating that continued pemvidutide treatment improved non-invasive tests such as Enhanced Liver Fibrosis (ELF) and Liver Stiffness Measurement (LSM) compared with placebo. 

Patients on the 1.8 mg dose experienced additional weight loss without a plateau, and the drug maintained a strong tolerability profile, with fewer discontinuations due to adverse events.

“The FDA’s Breakthrough Therapy Designation for pemvidutide in MASH reinforces the promise of its clinical profile and potential to address significant unmet needs in this serious, progressive liver disease.”

-Jerry Durso, President and CEO, Altimmune

Following a productive end-of-phase 2 meeting with the FDA, Altimmune finalized key parameters for a registrational Phase 3 trial in MASH patients with moderate-to-advanced liver fibrosis. The study will test multiple pemvidutide doses over a 52-week treatment period and incorporate biopsy-based results to support potential approval. 

ALT stock has declined by over 51% in the last 12 months. 

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