Altimmune Stock Runs Hot Ahead Of MASH Trial Readout; Retail Bulls Eye Big Win

Altimmune shares jumped during after-hours trading on Wednesday after the biotech firm said it would disclose top-line results from its 24-week Phase 2b IMPACT trial of pemvidutide for metabolic dysfunction-associated steatohepatitis (MASH) on Thursday.

The stock climbed 7.2% on Tuesday to close at $7.71 and extended its rally after hours with a 5.7% gain to $8.15.

The upcoming readout is seen as a key milestone for the company’s lead asset, pemvidutide, a GLP-1/glucagon dual receptor agonist being evaluated across multiple liver and metabolic indications, including obesity, alcohol use disorder (AUD), and alcohol-related liver disease (ALD).

Altimmune launched the RECLAIM Phase 2 trial of pemvidutide in AUD in May, aiming to reduce alcohol consumption in a population underserved by current treatment options. 

The company also plans to begin a Phase 2 study in ALD later this year.

Altimmune’s Chief Medical Officer, Scott Harris, previously noted that pemvidutide showed promising reductions in alcohol preference in preclinical models, suggesting potential crossover benefits for metabolic and addictive disorders.

Investors will be watching closely on Thursday for signs of efficacy in liver fat reduction, inflammation, and fibrosis, which are endpoints that could position pemvidutide as a competitive candidate in the growing MASH treatment landscape.

On Stocktwits, retail sentiment was ‘extremely bullish’ amid ‘extremely high’ message volume.

One user said if the data were negative, the company might have quietly published the topline results and followed up later with a management call to explain next steps. 

They suggested the only potential delay could be around fibrosis data, which may require the full 48-week readout.

Another trader pointed out that if the data were negative, the company might have pushed the announcement into next week’s July 4th holiday lull, when market activity is typically lower. 

Releasing it this Thursday instead, they argued, gives the stock another day to run, a move they believe hints at strong results.

The stock has risen 8.4% so far in 2025.

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