Altimmune to Present Results of Pemvidutide in MASH in an Oral Presentation and Multiple Poster Presentations at EASL Congress 2026

Abstract presenting 48-week IMPACT Phase 2b efficacy and safety data selected for inclusion in “Best of EASL 2026” by EASL

Oral presentation will highlight further the 48-week IMPACT efficacy and safety data

Late-breaker abstract featuring new digital pathology analysis of liver fibrosis regression from IMPACT 24-week data

GAITHERSBURG, Md., May 13, 2026 — Altimmune, Inc. (Nasdaq: ALT), a late clinical-stage biopharmaceutical company developing pemvidutide to address serious liver diseases, today announced that analyses of data from its IMPACT Phase 2b clinical trial in metabolic dysfunction-associated steatohepatitis (MASH) will be presented at the European Association for the Study of the Liver (EASL) Congress 2026, taking place May 27-30 in Barcelona, Spain.

Data will be featured in both an oral presentation and several poster sessions, including a late-breaking poster presentation. The company also announced that its abstract on 48-week results has been selected by EASL as Best of EASL 2026 in their summary deck for its noteworthy contribution to the scientific program of the EASL congress.

The oral presentation will showcase 48-week efficacy and safety results from the IMPACT Phase 2 trial, while additional poster presentations will focus on new 24-week findings, including digital pathology analysis of fibrosis regression, a response analysis to multiple non-invasive tests (NITs) of liver inflammation and fibrosis and data on cardiovascular measures.

Oral Presentation

Abstract Title: Week 48 Top-Line Results from the Phase 2b, Multicenter, Randomized, Placebo-Controlled IMPACT Trial of Pemvidutide in Metabolic Dysfunction-Associated Steatohepatitis Session: MASLD: Clinical and Therapeutic Aspects I (OS-016) Date/Time: Thursday, May 28, 17:00 CEST Presenter: Dr. Mazen Noureddin, Professor of Medicine, Houston Methodist Hospital; Chief Scientific Officer and Co-Chairman, Summit Clinical Research

Poster Presentations

Late-Breaking Poster

Abstract Title: Pemvidutide Treatment Led to Fibrosis Regression After 24 Weeks in Patients with MASH: Quantitative Digital Pathology Analysis from the Phase 2b IMPACT Trial Session: Late Breaker Posters (LBP-036) Date/Time: Wednesday, May 27, 08:30 CEST Presenter: Dr. Shaheen Tomah, Director, Clinical Development, Altimmune

Poster Presentation

Abstract Title: Concurrent Responses in Multiple Non-Invasive Tests for Hepatic Inflammation and Fibrosis Following Pemvidutide Treatment: 24-Week Responder Analyses from the Phase 2b IMPACT Trial Session: MASLD: Therapy (TOP-176) Date/Time: Friday, May 29, 08:30-17:00 CEST Presenter: Dr. Scot Roberts, Chief Scientific Officer, Altimmune

Poster Presentation

Abstract Title: Effect of Pemvidutide on Cardiovascular Risk Factors in Patients with MASH: 48-Week Results from the Phase 2b IMPACT Trial Session: MASLD: Therapy (FRI-201) Date/Time: Friday, May 29, 08:30-17:00 CEST Presenter: Dr. Shaheen Tomah, Director, Clinical Development, Altimmune

A copy of the oral presentation and posters will be available in the Events section of the Altimmune website.

About the IMPACT Phase 2b Study

The randomized, placebo-controlled, double-blind IMPACT Phase 2b trial (NCT05989711) enrolled 212 participants with biopsy-confirmed metabolic dysfunction-associated steatohepatitis (MASH) and fibrosis stages F2 or F3, with and without diabetes. Study participants were randomized 1:2:2 to receive weekly subcutaneous pemvidutide doses at either 1.2 mg, 1.8 mg or placebo for 48 weeks. The primary efficacy endpoints, measured at 24 weeks, were MASH resolution without worsening of fibrosis, or fibrosis improvement without worsening of MASH. Secondary endpoints included non-invasive tests of fibrosis and weight loss measured at 24 and 48 weeks.

About Pemvidutide

Pemvidutide is a novel, investigational peptide with balanced 1:1 glucagon/GLP-1 dual receptor agonist activity, in development for the treatment of metabolic dysfunction-associated steatohepatitis (MASH), alcohol use disorder (AUD) and alcohol-associated liver disease (ALD). The activation of glucagon receptors results in direct effects on the liver, including reductions in liver fat, inflammation and fibrosis, while GLP-1 receptors mediate metabolic effects such as appetite suppression and weight loss.

The FDA granted Fast Track designations to pemvidutide for the treatment of MASH and AUD, as well as Breakthrough Therapy Designation for MASH. In December 2025, the Company announced 48-week data from the IMPACT Phase 2b trial in MASH. The Phase 2 RECLAIM trial in AUD and RESTORE trial in ALD were initiated in May 2025 and July 2025, respectively, and are currently ongoing.

About Altimmune

Altimmune is a late clinical-stage biopharmaceutical company developing therapies for patients with serious liver diseases. The Company’s lead candidate, pemvidutide, is a unique dual-action therapy targeting both glucagon and GLP-1 receptors in a balanced 1:1 ratio in development for the treatment of metabolic dysfunction-associated steatohepatitis (MASH), alcohol use disorder (AUD) and alcohol-associated liver disease (ALD). For more information, please visit www.altimmune.com.

Follow @Altimmune, Inc. on LinkedIn**.**

Follow @AltimmuneInc on X**.**

Investor Contact

Luis Sanay, CFA Vice President, Investor Relations [email protected]

Media Contact

Real Chemistry [email protected]