On December 18, 2025, Altimmune announced 48-week data from the IMPACT Phase 2b trial of pemvidutide for MASH (metabolic dysfunction-associated steatohepatitis). While the company highlighted “key measures of success” including improvements in non-invasive fibrosis markers (ELF, LSM, cT1), sustained weight loss, and favorable safety, the stock fell by more than 20% in the following sessions.