Arbutus Reports Third Quarter 2025 Financial Results and Provides Corporate Update

WARMINSTER, Pa., Nov. 13, 2025 (GLOBE NEWSWIRE) -- Arbutus Biopharma Corporation (Nasdaq: ABUS) (“Arbutus” or the “Company”), a clinical-stage biopharmaceutical company focused on infectious disease, today reported third quarter 2025 financial results and provided a corporate update.

“The strength of our third quarter performance reflects our disciplined focus on executing strategic priorities,” said Lindsay Androski, President and CEO of Arbutus. “We are also excited to share additional analysis of imdusiran clinical data being conducted as part of our ongoing strategic review. Notably, in addition to the eight patients who initially achieved functional cure with imdusiran at 60mg in our Phase 2a trials, forty more patients across all cohorts discontinued nucleos(t)ide analogue therapy after meeting study-defined criteria. In total, a combined 46% of all Phase 2a patients were able to discontinue all treatment. All but one patient who achieved functional cure or who we are following after discontinuing nucleos(t)ide analogue therapy remain off all treatment long-term, now exceeding two years for some patients. Across our Phase 1b and Phase 2a trials, imdusiran has demonstrated sustained benefits in chronic hepatitis B patients, regardless of baseline hepatitis B surface antigen levels, hepatitis B virus DNA presence or absence, and hepatitis B e-antigen positivity or negativity. We remain dedicated to accelerating the development and potential approval of imdusiran.”

As of September 30, 2025, the Company had cash, cash equivalents and investments in marketable securities of $93.7 million compared to $122.6 million as of December 31, 2024. During the nine months ended September 30, 2025, the Company used $35.0 million in operating activities, which included one-time payments related to its restructuring efforts. This was partially offset by $3.9 million of proceeds from the exercise of stock options.

Total revenue was $0.5 million for the quarter ended September 30, 2025, compared to $1.3 million for the same period in 2024. The decrease of $0.8 million was due to a decrease in license royalty revenues, primarily due to a decline in Alnylam’s sales of ONPATTRO.

Research and development expenses were $5.8 million for the quarter ended September 30, 2025, compared to $14.3 million for the same period in 2024. The decrease of $8.5 million was due primarily to cost savings from the Company’s decisions to streamline the organization to focus its efforts on advancing the clinical development of imdusiran and AB-101, which included ceasing all discovery efforts, discontinuing its IM-PROVE III clinical trial, and reducing the Company’s workforce.

General and administrative expenses were $3.0 million for the quarter ended September 30, 2025, compared to $4.5 million for the same period in 2024. This decrease was due primarily to cost-cutting efforts by the Company, which drove reductions in employee compensation-related expenses and legal fees.

Restructuring costs in the quarter ended September 30, 2025 were $0.1 million, and all remaining restructuring-related payments are expected to be made by the first quarter of 2026.

For the quarter ended September 30, 2025, the Company’s net loss was $7.7 million, or a loss of $0.04 per basic and diluted common share, as compared to a net loss of $19.7 million, or a loss of $0.10 per basic and diluted common share, for the quarter ended September 30, 2024.

As of September 30, 2025, the Company had 192.0 million common shares issued and outstanding, as well as 14.9 million stock options and unvested restricted stock units outstanding.

Imdusiran is an RNAi therapeutic specifically designed to reduce all hepatitis B viral proteins and antigens including HBsAg, which is thought to be a key prerequisite to enable reawakening of a patient’s immune system to control the virus. Imdusiran targets hepatocytes using Arbutus’ novel covalently conjugated N-Acetylgalactosamine (“GalNAc”) delivery technology enabling subcutaneous delivery. To date, Arbutus has reported a total of eight patients with cHBV who have achieved a functional cure following treatment with imdusiran and NA therapy in combination with either IFN or low dose nivolumab plus an immunotherapeutic, with seven out of the eight patients continuing to sustain functional cure for over a year after treatment. An additional 40 patients across our Phase 2a clinical trials were able to remain off NA therapy for at least 48 weeks after discontinuing NA therapy following treatment with imdusiran. Clinical data generated thus far has shown imdusiran to be generally safe and well-tolerated, while also providing meaningful reductions in HBsAg and hepatitis B virus DNA.

Hepatitis B is a potentially life-threatening liver infection caused by HBV. HBV can cause chronic infection which leads to a higher risk of death from cirrhosis and liver cancer. cHBV infection represents a significant unmet medical need. The World Health Organization estimates that over 250 million people worldwide suffer from cHBV infection, while other estimates indicate that approximately 2 million people in the United States suffer from cHBV infection. Approximately 1.1 million people die every year from complications related to cHBV infection despite the availability of effective vaccines and current treatment options.

Arbutus Biopharma Corporation (Nasdaq: ABUS) is a clinical-stage biopharmaceutical company focused on infectious disease. The Company is currently developing imdusiran (AB-729) and an oral PD-L1 inhibitor (AB-101) for the treatment of cHBV infection. The Company is also consulting closely with and supporting its exclusive licensee, Genevant Sciences, to protect and defend its intellectual property, which is the subject of on-going lawsuits against Moderna and Pfizer/BioNTech for use of Arbutus’s patented LNP technology in their COVID-19 vaccines. For more information, visitwww.arbutusbio.com.

This press release contains forward-looking statements within the meaning of the Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934, and forward-looking information within the meaning of Canadian securities laws (collectively, forward-looking statements). Forward-looking statements in this press release include statements about: the potential to lead to a functional cure for HBV and/or the discontinuation of HBV therapies after treatment with Arbutus’ product candidates; the durability of clinical benefits from Arbutus’ product candidates; the potential for Arbutus’ product candidates to achieve success in clinical trials; Arbutus’ pipeline and development plans for its cHBV programs; and Arbutus’ plans with respect to the ongoing patent litigation matters, and the expected timing thereof.

With respect to the forward-looking statements contained in this press release, Arbutus has made numerous assumptions regarding, among other things: the effectiveness and timeliness of clinical trials, and the usefulness of the data; the continued demand for Arbutus’ assets; and the stability of economic and market conditions. While Arbutus considers these assumptions to be reasonable, these assumptions are inherently subject to significant business, economic, competitive, market and social uncertainties and contingencies. Additionally, there are known and unknown risk factors which could cause Arbutus’ actual results, performance or achievements to be materially different from any future results, performance or achievements expressed or implied by the forward-looking statements contained herein. Known risk factors include, among others: ongoing and anticipated clinical trials may be more costly or take longer to complete than anticipated, and may never be initiated or completed, or may not generate results that warrant future development of the tested product candidate; Arbutus may elect to change its strategy regarding its product candidates and clinical development activities; Arbutus may not receive the necessary regulatory approvals for the clinical development of Arbutus’ product candidates; uncertainties associated with litigation generally and patent litigation specifically; economic and market conditions may worsen; market shifts may require a change in strategic focus; Arbutus’ workforce reduction and plans to reduce its net cash burn may not materially extend the cash runway and may create a distraction or uncertainty that may adversely affect its operating results, business, or investor perceptions; and risks related to the sufficiency of Arbutus’ cash resources for its foreseeable and unforeseeable operating expenses and capital expenditures.

A more complete discussion of the risks and uncertainties facing Arbutus appears in Arbutus’ Annual Report on Form 10-K, Arbutus’ Quarterly Reports on Form 10-Q and Arbutus’ continuous and periodic disclosure filings, which are available atwww.sedar.comand atwww.sec.gov. All forward-looking statements herein are qualified in their entirety by this cautionary statement, and Arbutus disclaims any obligation to revise or update any such forward-looking statements or to publicly announce the result of any revisions to any of the forward-looking statements contained herein to reflect future results, events or developments, except as required by law.