Aligos Therapeutics Presents Positive Data at the EASL Congress 2026

• Long-term follow up data from the Phase 1 study of pevifoscorvir sodium continues to suggest a reduction in the cccDNA reservoir

• Data on the preclinical characteristics of the Aligos/Amoytop ASO program to be presented

• 40% of HBeAg+ participants with chronic HBV infection treated with pevifoscorvir sodium at week 48 had reductions in HBsAg that would potentially allow them to qualify for ASO treatment

SOUTH SAN FRANCISCO, Calif., May 27, 2026 (GLOBE NEWSWIRE) -- Aligos Therapeutics, Inc. (Nasdaq: ALGS), a clinical stage biopharmaceutical company focused on improving patient outcomes through best-in-class therapies for liver and viral diseases, today announced positive data from ten presentations at the European Association for the Study of the Liver (EASL) Congress 2026, being held May 27 – 30, 2026 in Barcelona, Spain.

“We are pleased to present positive data, including an investigator led study of ≥24 week follow up in HBeAg+ participants with nucleos(t)ide analogs (NAs) after 96 weeks of pevifoscorvir sodium monotherapy, which further supports our belief that we are reducing the cccDNA reservoir by activating the secondary mechanism of CAM-Es. By accessing this mechanism, we are also reducing HBsAg to a level that may allow additional patients to be eligible for functional cure therapy, including the ASO ALG-170675, being developed by Aligos and partner Amoytop,” stated Lawrence Blatt, Ph.D., M.B.A., Chairman, President, and Chief Executive Officer of Aligos Therapeutics. “Further, we will present data demonstrating that the combination of pevifoscorvir sodium and our antisense oligonucleotide ALG-170675 showed an additive to synergistic effects on reductions in HBV viral markers. Taken together, these data signal that pevifoscorvir sodium has the potential to not only replace NAs as the standard of care for chronic HBV infection but play a meaningful part in a functional cure regimen.”

Pevifoscorvir Sodium Post Treatment Data

Newly presented data highlight outcomes for treatment-naïve or currently not treated HBeAg+ subjects who completed 96 weeks of 300 mg pevifoscorvir sodium monotherapy, followed by ≥24 weeks of nucleos(t)ide analog (NA) monotherapy. Among HBeAg+ subjects, 9 of 10 subjects transitioned to NA monotherapy; of these, 4 (44%) maintained HBV DNA levels below the lower limit of quantification (LLOQ; 10 IU/mL, target detected [TD] or target not detected [TND]) throughout the NA only ≥24 week follow-up period. Reductions in HBV antigens and HBV RNA were maintained during the NA only ≥24 week follow-up period. Notably, these viral biomarkers, such as HBV antigens and HBV RNA, are typically unaffected by NA therapy, suggesting that pevifoscorvir sodium may reduce the cccDNA reservoir through engagement of its secondary mechanism of action.

In addition, newly presented data showed that among participants with a baseline HBsAg ≥3,000 IU/mL, 40% (4/10) achieved HBsAg <3,000 IU/mL at 48 weeks, suggesting eligibility for a functional cure regimen, which may include an antisense oligonucleotide (ASO) agent. In clinical trials conducted to date, certain ASO agents under development for chronic HBV infection have seen 20-30% functional cure rates in a patient population of HBsAg <3,000 IU/mL.

Additionally, preclinical in vitro data demonstrated that long-term treatment with ALG-001075, the active parent moiety of pevifoscorvir sodium, resulted in profound suppression of HBeAg, HBsAg and intracellular HBV RNAs which was durable after treatment withdrawal in HBV-infected HepaRG cells, suggesting a potential reduction in cccDNA level and/or transcriptional activity.

Preclinical Data

The preclinical posters showcased Aligos’ and its collaborators’ continued innovation and commitment to advancing next-generation therapies in the liver and viral spaces with presentations spanning novel approaches and mechanistic insights.

In particular, an analog of ALG-170675, a potential best-in-class antisense oligonucleotide (ASO), demonstrated an additive to synergistic effect when combined in vitro and in vivo with ALG-001075, the active parent moiety of pevifoscorvir sodium.

Additionally, in vitro data from the hepatitis delta virus (HDV) program demonstrates how the novel approach of targeting HDV replication could be a valuable addition to the current therapeutic arsenal.

Details on the presentations are as follows:

Abstract #:588Title:Sustained reduction of HBV antigen levels at ≥6 months follow-up in HBeAg-positive participants with chronic hepatitis B infection after 96 weeks of 300 mg pevifoscorvir sodium monotherapyPresenter:Professor Lung-Yi Mak, MBBS(HK), MD(HK), MRCP(UK), PDipID (HK), FHKCP, FHKAM (Medicine), FRCP (Glasg), FRCP (Edin), FRCP, Clinical Assistant Professor at The University of Hong KongDate/Time:May 27, 2026 at 8:30am – 5:00pm CETSession:Poster Tour – Track 8 – Viral Hepatitis; Viral Hepatitis B and D: New therapies, unapproved therapies or strategies

Abstract #:602Title:Pevifoscorvir sodium demonstrated profound antiviral activity in untreated HBeAg+ subjects, regardless of baseline ALT levelPresenter:Professor Man-Fung Yuen, MBBS, MD, PhD, DSc, Chair and Chief of the Division of Gastroenterology and Hepatology, University of Hong KongDate/Time:May 27, 2026 at 8:30am – 5:00pm CETSession:Poster Tour – Track 8 – Viral Hepatitis; Viral Hepatitis B and D: New therapies, unapproved therapies or strategies

Abstract #:586Title:Population pharmacokinetics of pevifoscorvir sodium (ALG-000184) in healthy participants and participants with chronic hepatitis B in support of phase 2 dose selectionPresenter:Kha Le, PhDDate/Time:May 27, 2026 at 8:30am – 5:00pm CETSession:Viral Hepatitis B and D: New therapies, unapproved therapies or strategies

Abstract #:570Title:ALG-001075, the parent of pevifoscorvir sodium, exhibits potent in vitro antiviral properties compared to other HBV capsid assembly modulators in clinical developmentPresenter:Yannick Debing, PhDDate/Time:May 28, 2026 at 8:30am – 5:00pm CETSession:Viral Hepatitis: Experimental and pathophysiology

Abstract #:634Title:Potent and durable off-treatment reduction of HBsAg levels and cccDNA-derived transcripts by the CAM-E ALG-001075 in cell-based experimentsPresenter:Professor Barbara Testoni, PhD, HDR, DR2 INSERM - Team Leader "Hepatitis Viruses and Liver pathogenesis". Université Claude Bernand Lyon 1, Inserm UMR 1350 - PaThLivDate/Time:May 28, 2026 at 8:30am – 5:00pm CETSession:Viral Hepatitis: Experimental and pathophysiology

Abstract #:587Title:The potentially best-in-class HBV ASO ALG-170674 demonstrates additive to synergistic antiviral activities when combined with other anti-HBV modalitiesPresenter:Jin Hong, PhDDate/Time:May 28, 2026 at 8:30am – 5:00pm CETSession:Viral Hepatitis: Experimental and pathophysiology

Abstract #:184Title:Synergistic fat mass loss in diet-induced obese mice when thyroid hormone receptor-β agonist ALG-055009 was administered in combination with incretin receptor agonistsPresenter:Xuan Luong, PhDDate/Time:May 30, 2025 at 8:30am – 4:00pm CETSession:Poster - MASLD: Experimental and pathophysiology

Abstract #:606Title:Antisense oligonucleotide-based strategy to target hepatitis delta virus infectionsPresenter:Julie Lucifora, PhD, HDR, Director of Research, INSERM, CIRI - Centre International de Recherche en InfectiologieDate/Time:May 28, 2026 at 12:45 – 1:45pm CET; May 28, 2026 at 8:30am – 5:00pm CETSession:Poster Tour – Track 8 – Viral Hepatitis; Viral Hepatitis: Experimental and pathophysiology

Abstract #:610Title:Discovery of novel HDV entry inhibitors with selectivity over bile acid inhibitionPresenter:David McGowan, MSDate/Time:May 28, 2026 at 8:30am – 5:00pm CETSession:Viral Hepatitis: Experimental and pathophysiology

Abstract #:620Title:Preclinical characterization of ALG-093940, a potent and orally bioavailable small molecule PD-1/PD-L1 inhibitor for the treatment of chronic hepatitis B infection and liver cancerPresenter:Heleen Roose, PhDDate/Time:May 28, 2026 at 8:30am – 5:00pm CETSession:Viral Hepatitis: Experimental and pathophysiology

The presentations can be found on the Posters & Presentations section of the Aligos website (www.aligos.com) after the live event.

Aligos Therapeutics, Inc. (NASDAQ: ALGS) is a clinical stage biotechnology company founded with the mission to improve patient outcomes by developing best-in-class therapies for the treatment of liver and viral diseases. Aligos applies its science driven approach and deep R&D expertise to advance its purpose-built pipeline of therapeutics for high unmet medical needs such as chronic hepatitis B virus infection, metabolic dysfunction-associated steatohepatitis (MASH), obesity, and coronaviruses.

For more information, please visitwww.aligos.comor follow us on LinkedIn or X.

This press release contains forward-looking statements within the meaning of the U.S. Private Securities Litigation Reform Act of 1995. Any statements in this press release that are not historical facts may be considered “forward-looking statements,” including without limitation, statements regarding Aligos’ financial results and performance as well as research and development activities, including regulatory status and the timing of announcements and updates relating to our regulatory filings and clinical trials; statements about the potential benefits of pevifoscorvir sodium including its potential to replace NAs as the standard of care for chronic HBV infection and be part of a functional cure regimen, and whether the B-SUPREME study will show superiority of pevifoscorvir sodium over NAs; statements about whether pevifoscorvir sodium will be shown to reduce the cccDNA reservoir; and statements about the potential benefits of combining pevifoscorvir sodium with an ASO agent. Such forward looking statements are subject to substantial risks and uncertainties that could cause our development programs, future results, performance, or achievements to differ materially from those anticipated in the forward-looking statements. Such risks and uncertainties include, without limitation, risks and uncertainties inherent in the drug development process, including Aligos’ clinical-stage of development, the process of designing and conducting clinical trials, the regulatory approval processes, and other matters that could affect the sufficiency of Aligos’ capital resources to fund operations. For a further description of the risks and uncertainties that could cause actual results to differ from those anticipated in these forward-looking statements, as well as risks relating to the business of Aligos in general, see Aligos’ Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on May 7, 2026 and its future periodic reports to be filed or submitted with the Securities and Exchange Commission. Except as required by law, Aligos undertakes no obligation to update any forward-looking statements to reflect new information, events or circumstances, or to reflect the occurrence of unanticipated events.

Investor ContactAligos Therapeutics, Inc.Jordyn TaraziVice President, Investor Relations & Corporate Communications+1 (650) 910-0427jtarazi@aligos.com