WARMINSTER, PA — Arbutus Biopharma Corporation (Nasdaq: ABUS) reported third quarter 2025 financial results and released new analyses showing sustained, long-term therapeutic benefit from its chronic hepatitis B candidate imdusiran (AB-729). The company also highlighted progress in its high-profile lipid nanoparticle (LNP) litigation against Moderna and Pfizer/BioNTech, with the first U.S. jury trial now set for March 2026.
Arbutus ended the quarter with $93.7 million in cash, cash equivalents, and marketable securities, providing a substantial foundation as it advances imdusiran toward potential registration pathways and supports ongoing global IP enforcement efforts.
Lindsay Androski, Arbutus’ president and CEO, said the latest clinical analysis reinforces imdusiran’s potential to change the long-challenging HBV treatment landscape. Across Phase 2a studies, 46% of patients met the criteria to discontinue all therapy following imdusiran treatment. Of those entering long-term follow-up, 94% have remained off treatment for up to two years, including patients with diverse genotypes, baseline antigen profiles, and viral loads.
Updated findings also show:
- All HBV DNA–positive Phase 1b patients achieved HBV DNA levels below quantification within 18 weeks on imdusiran plus nucleos(t)ide analogue therapy.
- All hepatitis B e-antigen–positive patients demonstrated dose-dependent reductions in HBeAg.
- In Phase 1b, 56% of patients who voluntarily discontinued background therapy remained off all treatment for at least three years.
Arbutus said these results demonstrate durable viral control, deep antigen suppression, and a consistent response pattern across patient subgroups. The company continues to evaluate strategic next steps for late-stage development.
On the litigation front, Arbutus and its partner Genevant Sciences are pursuing compensation for what they describe as Moderna’s and Pfizer/BioNTech’s unlicensed use of its LNP technology in their COVID-19 vaccines. In the Moderna case, discovery and summary judgment briefings have been completed, with a jury trial set for March 2026. Additional international actions filed across 30 countries are progressing, including Unified Patent Court hearings scheduled for May 2026 and a Canadian trial planned for September 2027.
The Pfizer/BioNTech case advanced in September 2025 with a claim construction ruling the company described as generally favorable.
Arbutus also showcased four hepatitis B program presentations at AASLD 2025, including an analysis showing clinical benefit across HBV genotypes A through E and new data demonstrating AB-101’s PD-L1 receptor occupancy reached as high as 100% at a 30 mg daily dose.
Financial results reflected the company’s restructuring efforts to streamline operations around its core HBV programs. Research and development spending fell sharply to $5.8 million from $14.3 million a year earlier following the discontinuation of discovery activities, closure of the IM-PROVE III trial, and staffing reductions. General and administrative expenses dropped to $3.0 million from $4.5 million. Net loss narrowed to $7.7 million, compared to $19.7 million in the third quarter of 2024.
Arbutus had 192.0 million shares outstanding as of September 30, 2025, along with 14.9 million stock options and unvested restricted stock units.
With a strengthened balance sheet, accelerating HBV data, and litigation milestones approaching, the company enters 2026 with what leadership describes as a clear focus on advancing imdusiran and protecting its foundational LNP technology.
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