Altimmune Faces Lawsuits Over Alleged Misleading Trial Data
Multiple law firms have filed class-action lawsuits alleging securities fraud after the company's MASH drug trial failed to meet key endpoints.
Altimmune, Inc. (NASDAQ: ALT) is facing mounting legal pressure as multiple law firms have filed class-action lawsuits on behalf of investors. The suits allege the clinical-stage biopharmaceutical company engaged in securities fraud by making false and misleading statements about its drug candidate, pemvidutide, leading to significant investor losses after a pivotal trial failed.
The legal actions follow the company's June 26, 2025, announcement of topline results from its IMPACT Phase 2b trial for MASH (metabolic dysfunction-associated steatohepatitis). The trial did not achieve statistical significance for its primary endpoint of fibrosis reduction. The company attributed the outcome to a higher-than-expected placebo response, but the market reacted harshly. On the day of the news, Altimmune's stock price plummeted 53.2%, falling $4.10 to close at $3.61 per share, erasing substantial market value.
The lawsuits claim that Altimmune had provided overly optimistic and inflated expectations ahead of the results. Law firms, including Pomerantz LLP, have concerning whether the company and its directors engaged in unlawful business practices. According to the complaints, the company's public statements were materially misleading throughout the class period, which runs from August 10, 2023, to June 25, 2025.
, encouraging investors who suffered losses to come forward. Investors who purchased securities within the specified period have until October 6, 2025, to apply to the court to be appointed as a lead plaintiff. The legal actions cast a shadow over the future development of pemvidutide and have created significant uncertainty for Altimmune as it navigates both the clinical and legal challenges ahead.