Altimmune Receives FDA Breakthrough Therapy Designation for Pemvidutide in MASH

Rhea-AI Summary

Altimmune (NASDAQ: ALT) ha annunciato che la Food and Drug Administration statunitense ha concesso Breakthrough Therapy Designation per pemvidutide per trattare la steatoepatite associata a disfunzione metabolica (MASH) il 5 gennaio 2026. La designazione si è basata sui dati di 24 settimane dello studio IMPACT di fase 2b che hanno mostrato una risoluzione statisticamente significativa della MASH senza peggioramento della fibrosi e sui primi miglioramenti nel contenuto di grasso nel fegato e nei test non invasivi di fibrosi/infiammazione.

Altimmune ha riportato i dati principali a 48 settimane nel dicembre 2025 che mostrano ulteriori miglioramenti statisticamente significativi in ELF e LSM, una continuazione della perdita di peso alla dose di 1,8 mg e un profilo di tollerabilità favorevole. L'azienda e la FDA hanno concordato sui parametri della fase 3 registrazionale e pianificano una fase 3 di 52 settimane con endpoint di biopsia utilizzando dosi multiple e AIM-MASH AI Assist; sarà richiesto anche un parere scientifico europeo.

Positive

• FDA Breakthrough Therapy Designation granted for pemvidutide
• Phase 3 parameters aligned with FDA per end-of-phase 2 minutes
• IMPACT Phase 2b: 24-week statistical MASH resolution without fibrosis worsening
• 48-week topline: statistically significant ELF and LSM improvements
• 1.8 mg dose: continued weight loss at 48 weeks with favorable tolerability

Negative

• None.

Key Figures

IMPACT data duration 24 weeks Data supporting Breakthrough Therapy Designation submission

IMPACT data duration 48 weeks Topline IMPACT Phase 2b follow-up results

Pemvidutide dose 1.8 mg Dose showing continued weight loss and antifibrotic activity at 48 weeks

Phase 3 treatment length 52 weeks Planned registrational Phase 3 pemvidutide trial treatment period

Market Reality Check

$4.02 Last Close

Volume Volume 3,535,976 is below the 20-day average of 4,846,137 (relative volume 0.73x). normal

Technical Shares at $3.51 trade below the 200-day MA $4.58 and are 55.17% below the 52-week high of $7.83, while 21.03% above the 52-week low of $2.90.

Peers on Argus

ALT was down 2.77% pre-news with mixed peer moves: several biotech peers were also negative (e.g., ALDX -8.79%, LRMR -7.71%, DSGN -3.81%), while OCGN gained 1.47%, suggesting stock-specific factors rather than a uniform sector trend.

Historical Context

Date	Event	Sentiment	Move	Catalyst
Dec 19	Phase 2b 48-week data	Positive	-22.8%	Strong 48-week IMPACT data with significant fibrosis and liver fat improvements.
Dec 01	CEO succession	Neutral	-6.3%	CEO transition to Jerry Durso with Phase 3 readiness update for pemvidutide.
Nov 26	Conference participation	Neutral	+0.6%	Announcement of participation in Piper Sandler healthcare conference webcast.
Nov 11	Lancet publication	Positive	+0.5%	Lancet publication and AASLD talk on 24-week IMPACT data with strong efficacy.
Nov 07	AI fibrosis analysis	Positive	+4.3%	AI-based analysis showing significant fibrosis area reductions versus placebo.

Pattern Detected

Recent history shows positive pemvidutide data and regulatory milestones sometimes coinciding with negative price reactions, notably the -22.77% move on strong 48-week IMPACT Phase 2b results, while other positive data events saw modest gains.

Recent Company History

This announcement of FDA Breakthrough Therapy Designation for pemvidutide in MASH builds on a series of late-2025 milestones. On Nov 7 and Nov 11, 2025, Altimmune reported favorable IMPACT Phase 2b data, including strong MASH resolution, liver fat reductions, and fibrosis improvements, with small positive price reactions. A CEO transition on Dec 1, 2025 and highly positive 48-week IMPACT topline data on Dec 19, 2025 were followed by declines, including a -22.77% move, indicating historically mixed market responses to positive clinical news.

Regulatory & Risk Context

Active S-3 Shelf Registration 2025-11-13

$400,000,000 registered capacity

Altimmune has an active Form S-3/A shelf filed on Nov 13, 2025 to register up to $400,000,000 of mixed securities. The shelf was not yet effective and had no recorded usage before this news, but once effective it allows the company to raise capital for general corporate and development purposes via future offerings.

Market Pulse Summary

The stock surged +16.5% in the session following this news. A strong positive reaction aligns with the significance of FDA Breakthrough Therapy Designation for pemvidutide in MASH, building on prior Phase 2b IMPACT results and FDA alignment on Phase 3 design. However, Altimmune’s history includes sharp pullbacks after positive data, such as a -22.77% move on recent 48-week results, and an effective $400,000,000 shelf, once active, could enable future capital raises that may affect sentiment.

Key Terms

breakthrough therapy designation regulatory

"The FDA has granted Breakthrough Therapy Designation (BTD) for pemvidutide..."

A breakthrough therapy designation is a regulatory fast-track given to a drug or treatment that shows early signs of providing a major improvement over existing options for a serious condition. Think of it as a VIP lane that can speed up development and more intensive guidance from regulators, which matters to investors because it can shorten time to market, reduce development risk and potentially increase a company’s value — though it does not guarantee approval.

glucagon medical

"pemvidutide, a balanced 1:1 glucagon/GLP-1 dual receptor agonist..."

A hormone produced by the pancreas that raises blood sugar by prompting the liver to release stored sugar, acting like the body’s quick energy alarm. For investors, glucagon is important because it is both a key target for diabetes treatments and an approved emergency drug for severe low blood sugar, so changes in clinical data, approvals, manufacturing or demand can affect pharmaceutical and medical-device companies' revenue and valuation.

glp-1 medical

"pemvidutide, a balanced 1:1 glucagon/GLP-1 dual receptor agonist..."

GLP-1 (glucagon-like peptide-1) is a natural hormone in the body that helps regulate blood sugar levels and appetite. Its significance to investors lies in its role as the basis for a class of medications that address conditions like type 2 diabetes and obesity, which are large and growing markets. Advances or investments in GLP-1-based treatments can signal opportunities in healthcare innovation and potentially impact pharmaceutical companies’ growth.

metabolic dysfunction-associated steatohepatitis medical

"for the treatment of patients with metabolic dysfunction-associated steatohepatitis (MASH)."

Metabolic dysfunction-associated steatohepatitis is a liver disease in which fat buildup tied to metabolic problems such as obesity and diabetes leads to inflammation and scarring, like rust forming inside a machine that gradually impairs function. It matters to investors because its growing prevalence creates large markets for drugs, diagnostics and care, and clinical trial results, approvals, or reimbursement decisions can sharply change the value of healthcare companies working in this area.

enhanced liver fibrosis medical

"including Enhanced Liver Fibrosis (ELF) and Liver Stiffness Measurement (LSM)..."

A blood-based score that combines several biomarkers to estimate the amount of scar tissue in the liver, often reported as the Enhanced Liver Fibrosis (ELF) test. Investors care because it is used to gauge disease severity, select or monitor patients in clinical trials, and can influence the market potential and regulatory path for drugs and diagnostics targeting liver disease; think of it as a noninvasive 'check engine' light for liver scarring.

liver stiffness measurement medical

"including Enhanced Liver Fibrosis (ELF) and Liver Stiffness Measurement (LSM)..."

A liver stiffness measurement is a noninvasive test that gauges how firm or 'stiff' the liver has become, which reflects scarring (fibrosis) from chronic liver disease. Like pressing fruit to judge ripeness, the result helps doctors assess disease severity, monitor progression, and decide on treatment; for investors it influences the commercial prospects of therapies, diagnostic devices, clinical trial enrollment, and market demand for liver-related healthcare products.

non-invasive tests medical

"improvements in liver fat and non-invasive tests of fibrosis and hepatic inflammation."

Non-invasive tests are medical checks that gather diagnostic information without cutting into the body or inserting instruments into internal cavities, using methods like external imaging, breath or saliva sampling, and surface sensors. For investors, they matter because they tend to be lower-risk, quicker to adopt, cheaper to administer, and more acceptable to patients than surgical procedures, which can mean larger markets, faster revenue growth, and simpler regulatory paths.

ai pathology technical

"the use of AIM-MASH AI Assist, the first AI pathology tool qualified by the FDA..."

AI pathology is the use of artificial intelligence to analyze medical tissue images and related lab data to detect and classify diseases, acting like a digital assistant that flags abnormalities on microscope slides. It matters to investors because successful AI tools can speed diagnoses, lower costs, and open new software and service revenue streams for healthcare companies, while regulatory approvals, clinical adoption and accuracy determine commercial value and risk.

AI-generated analysis. Not financial advice.

Alignment on Phase 3 registrational trial parameters confirmed following receipt of minutes from end-of-phase 2 meeting with U.S. FDA

GAITHERSBURG, Md., Jan. 05, 2026 (GLOBE NEWSWIRE) -- Altimmune, Inc. (Nasdaq: ALT), a late clinical-stage biopharmaceutical company developing therapies that address serious liver diseases, today announced the U.S. Food and Drug Administration (FDA) has granted Breakthrough Therapy Designation (BTD) for pemvidutide, a balanced 1:1 glucagon/GLP-1 dual receptor agonist, for the treatment of patients with metabolic dysfunction-associated steatohepatitis (MASH).

Breakthrough Therapy Designation is intended to expedite the development and review of medicines that are intended to treat a serious or life-threatening condition and have shown preliminary clinical evidence indicating the potential for substantial improvement over available therapies on a clinically significant endpoint.

“The FDA’s Breakthrough Therapy Designation for pemvidutide in MASH reinforces the promise of its clinical profile and potential to address significant unmet needs in this serious, progressive liver disease,” said Jerry Durso, President and Chief Executive Officer of Altimmune. “As I step into the CEO role, this designation represents an important validation for pemvidutide. Phase 2b data support its differentiated profile and the meaningful role it could play in MASH, and potentially other serious liver diseases. With this breakthrough designation and alignment with the FDA on registrational Phase 3 trial parameters, we are laser-focused on strengthening the foundation of Altimmune to advance pemvidutide through late-stage development – guided by our commitment to serve patients and create value for our stakeholders.”

Breakthrough Therapy Designation for pemvidutide in MASH was granted based on submission of 24-week data from the IMPACT Phase 2b trial demonstrating statistically significant MASH resolution without worsening of fibrosis, along with early and substantial improvements in liver fat and non-invasive tests of fibrosis and hepatic inflammation. In December 2025, Altimmune reported 48-week topline IMPACT data showing that continued treatment with pemvidutide resulted in statistically significant improvements versus placebo in key non-invasive tests, including Enhanced Liver Fibrosis (ELF) and Liver Stiffness Measurement (LSM), with additional reductions from week 24 across both dose levels, supporting ongoing antifibrotic activity. At 48 weeks, patients receiving the 1.8 mg dose achieved further weight loss with no evidence of plateauing, and pemvidutide maintained the favorable tolerability profile observed at 24 weeks, including a lower discontinuation rate due to adverse events compared with placebo.

Altimmune completed a productive end-of-phase 2 meeting with the FDA last month, resulting in alignment on parameters for a registrational Phase 3 trial of pemvidutide in MASH patients with moderate to advanced liver fibrosis as reflected in the final meeting minutes. The Company plans to initiate a Phase 3 trial evaluating multiple pemvidutide doses over a 52-week treatment period. The trial is expected to incorporate biopsy-based endpoints to support a potential accelerated approval and the use of AIM-MASH AI Assist, the first AI pathology tool qualified by the FDA for use in MASH clinical trials. As previously disclosed, the Company also will be seeking scientific advice from European regulators, which will be considered when finalizing the Phase 3 protocol.

About MASH
Metabolic dysfunction-associated steatohepatitis (MASH) is a progressive liver disease marked by fat accumulation, inflammation, and fibrosis in the liver. Without treatment, it can progress to cirrhosis, liver failure, or liver cancer, and is one of the most common reasons for liver transplantation in the U.S. Currently approved treatment options may not fully address both the metabolic drivers and fibrosis that can pose long-term risk for patients living with MASH.

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. Phase 2 trials in AUD (RECLAIM) and ALD (RESTORE) 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.

Forward-Looking Statement
Any statements made in this press release related to the potential benefits of Breakthrough Therapy Designation, including regulatory timeline and approval benefits, the clinical trial results, development or commercialization of pemvidutide, an investigational product candidate, and other business, regulatory and financial matters including without limitation, the timing of key milestones for the Company’s clinical assets, future plans or expectations for pemvidutide for the treatment of MASH, meetings with the FDA, and the prospects for receiving regulatory approval or commercializing or selling any product or drug candidates, are forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. In addition, when or if used in this press release, the words "may," "could," "should," "anticipate," "believe," "estimate," "expect," "intend," "plan," "predict" and similar expressions and their variants, as they relate to Altimmune, Inc. may identify forward-looking statements. The Company cautions that these forward-looking statements are subject to numerous assumptions, risks, and uncertainties, which change over time. Important factors that may cause actual results to differ materially from the results discussed in the forward-looking statements, or historical experience include risks and uncertainties, including risks relating to: delays in regulatory review, manufacturing and supply chain interruptions, access to clinical sites, enrollment, adverse effects on healthcare systems and disruption of the global economy; the reliability of the results of studies relating to human safety and possible adverse effects resulting from the administration of the Company's product candidates; the Company's ability to manufacture clinical trial materials on the timelines anticipated; and the success of future product advancements, including the success of future clinical trials. Further information on the factors and risks that could affect the Company's business, financial conditions and results of operations are contained in the Company's filings with the U.S. Securities and Exchange Commission, including under the heading "Risk Factors" in the Company's most recent annual report on Form 10-K, quarterly report on Form 10-Q and the Company’s other filings with the SEC, which are available at www.sec.gov.

Investor Contact:
Lee Roth
Burns McClellan
Phone: 646-382-3403
lroth@burnsmc.com

Media Contact:
Savannah Valade
Real Chemistry
Altimmune@realchemistry.com

FAQ

What did Altimmune (ALT) announce about pemvidutide on January 5, 2026?

Altimmune announced FDA Breakthrough Therapy Designation for pemvidutide in MASH and alignment with the FDA on Phase 3 trial parameters.

Why did the FDA grant Breakthrough Therapy Designation to pemvidutide (ALT)?

The FDA based the designation on 24-week IMPACT Phase 2b data showing statistically significant MASH resolution without worsening fibrosis and early improvements in liver fat and non-invasive tests.

What Phase 3 trial will Altimmune (ALT) initiate for pemvidutide?

Altimmune plans a 52-week registrational Phase 3 evaluating multiple doses with biopsy-based endpoints to support potential accelerated approval.

What did Altimmune report in December 2025 about pemvidutide's 48-week results?

Topline 48-week data showed statistically significant improvements in ELF and LSM, additional reductions from week 24, and continued weight loss at the 1.8 mg dose with favorable tolerability.

Will the Altimmune Phase 3 use any AI tools for pathology scoring?

Yes — the trial is expected to use AIM-MASH AI Assist, noted as the first FDA-qualified AI pathology tool for MASH trials.

Will Altimmune (ALT) seek regulatory input outside the U.S. for pemvidutide Phase 3?

Yes — the company will seek scientific advice from European regulators to inform the Phase 3 protocol.