Class Action Filed Against Altimmune, Inc. – Investors with Losses Encouraged to Contact Johnson Fistel

Shareholder rights law firm Johnson Fistel, PLLP, announces that a class action lawsuit has been filed on behalf of investors who purchased securities of Altimmune, Inc. (“Altimmune”) (NASDAQ: ALT) between August 10, 2023 and June 25, 2025, inclusive (the “Class Period”). If you wish to serve as lead plaintiff, you must move the Court no later than October 6, 2025.

According to the complaint, on June 26, 2025, Altimmune published a press release announcing topline results from the IMPACT Phase 2b MASH trial of Pemvidutide in the Treatment of MASH. While defendants had continuously provided inflated expectations ahead of these results, the analysis showed a pointed failure by the Company to achieve statistical significance in its analysis of the fibrosis reduction primary endpoint in its IMPACT Phase 2b MASH trial. In particular, while a positive trend in fibrosis improvement was observed, statistical significance was not met due to a higher-than-expected placebo response. When questioned about this concerning miss, defendants answered indifferently, attributing this result to the Phase 2 nature of the trial and stated that Altimmune was hoping for better results following the Phase 3 trial.  Following this news, the price of Altimmune’s common stock declined dramatically. From a closing market price of $7.71 per share on June 25, 2025, Altimmune’s stock price fell to $3.61 per share on June 26, 2025, a decline of 53.2% in the span of just a single day.