Arbutus Biopharma to present 5 abstracts, including late-breaker, highlighting advancements in chronic hepatitis B treatment at EASL 2025

Arbutus Biopharma Corporation, a clinical-stage biopharmaceutical company focused on infectious disease, today announced that five abstracts, including one late-breaker, have been accepted for presentation at the European Association for the Study of the Liver (EASL) Congress 2025 taking place May 7 – 10, 2025 in Amsterdam, Netherlands.

The following abstracts will be presented as posters in the Viral Hepatitis B and D: New Therapies, Unapproved Therapies or Strategies session on May 8, 2025, from 8:30 am – 5:00 pm CET.

Abstract Number: 1768
Title: IM-PROVE I: characterization of chronic hepatitis B (CHB) subjects with functional cure or HBV DNA suppression after completion of imdusiran plus short courses of pegylated interferon alfa-2a (IFN) and discontinuation of nucleos(t)ide analogue (NA) therapy
Presenter: Prof. Man-Fung Yuen
Presentation Date: May 8, 2025
Key Findings: Within this small group of subjects who achieved functional cure or HBV DNA<LLOQ after NA discontinuation in the IM-PROVE I study, HBsAg at baseline and at the time of NA discontinuation appear to be the only factors associated with functional cure, with no apparent differences in other baseline characteristics or HBV biomarkers collected, including HBcrAg and HBV RNA. Additional analysis of this dataset is ongoing, and the potential association of baseline characteristics and HBV biomarkers with functional cure should continue to be evaluated in larger trials.

This will also be featured in the Poster Tour: Viral Hepatitis, on Thursday, May 8, 2025, at 16:22 CEST.

Abstract Number: 2043
Title: IM-PROVE I: Rapid loss followed by transient increases in HBV RNA in chronic hepatitis B
subjects during treatment with imdusiran and pegylated interferon alfa-2a is associated with HBsAg seroclearance
Presenter: Dr. Emily P. Thi
Presentation Date: May 8, 2025
Key Findings: Subjects who achieved functional cure after combination treatment with imdusiran plus interferon showed rapid HBV RNA decline during imdusiran lead-in, with 5 of 6 subjects achieving HBV RNA undetectability during this period. Transient elevations in HBV RNA were observed to occur during the interferon treatment period which was associated with further HBsAg decline and loss in some functional cure subjects.

Abstract Number: 1990
Title: First-in-human pharmacokinetics and pharmacodynamics of oral small-molecule
PD-L1 inhibitor AB-101 and correlation to preclinical models
Presenter: Dr. Emily P. Thi
Presentation Date: May 8, 2025
Key Findings: AB-101 was safe and well-tolerated in both single- and multiple-dose administrations in healthy subjects. Dose-responsive increases in PD-L1 receptor occupancy were observed in peripheral blood cells, which correlated with dose-dependent increases in AB-101 plasma concentrations. The clinical plasma PK profile of AB-101 to date indicates rapid distribution into tissues, mirroring the plasma profiles seen in preclinical efficacy models, which exhibited high liver biodistribution and target engagement.

Abstract Number: 1978
Title: Preliminary safety, tolerability, pharmacokinetics and pharmacodynamics of single and multiple doses of AB-101, a small-molecule PD-L1 inhibitor, in healthy and chronic hepatitis B subjects
Presenter: Prof. Edward J. Gane
Presentation Date: May 8, 2025
Key Findings: Single doses of AB-101 up to 40 mg and repeat doses up to 40 mg QD for 7 days were well tolerated in healthy subjects. Preliminary PD data shows AB-101 receptor occupancy at doses ≥ 10 mg, with dose-responsive increases in PD-L1 receptor occupancy observed. Dosing in Part 3 in CHB subjects is ongoing and available data, including receptor occupancy and HBV virologic biomarkers, will be presented.

The following late-breaker poster will be presented on May 7, 2025:

Abstract Number: LB25153
Title: Off-treatment antiviral efficacy and safety of repeat dosing of imdusiran followed by VTP-300 with or without nivolumab in virally-suppressed, non-cirrhotic subjects with chronic hepatitis B (CHB)
Presenter: Dr. Grace Lai-Hung Wong

Abstracts are available on the EASL Congress 2025 website at https://www.easlcongress.eu/. The posters are expected to be made available to conference attendees at the start of the meeting on May 7, 2025, and will be available subsequently on Arbutus’ website at https://www.arbutusbio.com/publications/.