ABUS

Maintained strong financial position with cash, cash equivalents and marketable securities of $92.6M as of June 30, 2026 Received first payment of approximately $178M from Moderna settlement in July and expects to return up to approximately $230M in capital to Arbutus shareholders Filed three international patent enforcement lawsuits against Pfizer and BioNTech related to lipid nanoparticle (LNP) technology Achieved alignment with the U.S. Food and Drug Administration (FDA) on a proposed imdusiran Phase 2b clinical trial design WARMINSTER, Pa., Aug. 12, 2026 (GLOBE NEWSWIRE) -- Arbutus Biopharma Corporation (Nasdaq: ABUS) (“Arbutus” or the “Company”), a clinical-stage biopharmaceutical company focused on infectious disease, today reported second quarter 2026 financial results and provided a corporate update. LNP Litigation On March 3, 2026, Arbutus, along with its exclusive licensee, Genevant Sciences (“Genevant”), entered into a settlement agreement to resolve all global patent infringement litigation and patent revocation proceedings involving Moderna. As part of the settlement, Moderna paid Arbutus and Genevant $950 million in July 2026 (the “Noncontingent Settlement Payment”) and will pay an additional $1.3 billion contingent upon an appellate ruling that 28 U.S.C. §1498 does not bar Arbutus’ and Genevant’s claims against Moderna for patent infringement, except as to doses characterized by the district court as having gone to U.S. government employees. On July 8, 2026, the Company received $178.4 million as its share of the Noncontingent Settlement Payment, which includes reimbursement of the Company’s litigation costs. In addition, the Company owns approximately 16% of the outstanding common equity of Genevant and anticipates the payment of a material dividend from Genevant in the third quarter of 2026. For more information about the terms and conditions of the settlement with Moderna, including the contingent payment, please refer to Arbutus’ Quarterly Report on Form 10-Q to be filed with the SEC on August 12, 2026 and Annual Report on Form 10-K filed with the SEC on March 23, 2026. In July 2026, the Company, along with Genevant, filed three international lawsuits against Pfizer, BioNTech and certain of their affiliates seeking to enforce patents protecting the Company’s patented LNP technology across 21 countries. Corporate Updates Arbutus expects to return capital to shareholders commencing in Q3 2026 through repurchases of up to approximately $230 million of the Company’s common shares, which repurchases may come in the form of a tender offer (including a modified “Dutch Auction” tender offer), open market purchases, accelerated share repurchases or other means. The specific form(s) of any such transaction(s) remains subject to the approval of the Company’s board of directors, and no assurance can be given that any such repurchase activity will occur in Q3 2026, or at all. In April 2026, the FDA granted Fast Track designation for imdusiran for the treatment of chronic hepatitis B (“cHBV”). The FDA’s Fast Track program is designed to facilitate the development and expedite the review of investigational therapies to treat serious conditions with unmet medical need. In May 2026, the Company reached alignment with the FDA on the design and safety parameters of a proposed Phase 2b clinical trial evaluating imdusiran for the treatment of cHBV. The Company intends to incorporate the FDA’s feedback into a final Phase 2b protocol. “This has been an exciting quarter for our imdusiran development program,” said Lindsay Androski, President and CEO of Arbutus. “In addition to obtaining Fast Track designation from the FDA on this promising drug candidate, which has achieved functional cure in 10 chronic hepatitis B patients to date, we reached alignment with the FDA on the design of our Phase 2b clinical trial. I would like to publicly congratulate our research and development team for their hard work and dedication in achieving these important milestones.” Financial Results Cash, Cash Equivalents and Investments As of June 30, 2026, the Company had cash, cash equivalents and investments in marketable securities of $92.6 million compared to $91.5 million as of December 31, 2025. During the six months ended June 30, 2026, the Company used $14.1 million in operating activities, which included one-time payments related to its restructuring efforts, and received $14.7 million of proceeds from the exercise of stock options. Revenue Total revenue was $1.0 million for the quarter ended June 30, 2026, compared to $10.7 million for the same period in 2025. The decrease of $9.7 million was due primarily to recognizing in the quarter ended June 30, 2025 all $9.6 million of previously deferred revenue upon conclusion of the Company’s strategic partnership with Qilu in June 2025. Operating Expenses Research and development expenses were $2.9 million for the quarter ended June 30, 2026, compared to $5.5 million for the same period in 2025. The decrease of $2.6 million was due primarily to cost savings from the Company’s decisions to reduce its workforce and discontinue in-house scientific research, as well as lower clinical trial costs as studies neared completion. General and administrative expenses were $3.9 million for the quarter ended June 30, 2026, compared to $3.3 million for the same period in 2025. This increase was due primarily to higher stock compensation expenses. There were no restructuring costs in the quarter ended June 30, 2026, compared to $0.2 million for the same period in 2025. Net Income/Loss For the quarter ended June 30, 2026, the Company’s net loss was $5.1 million, or a loss of $0.03 per basic and diluted common share, as compared to net income of $2.5 million, or income of $0.01 per basic and diluted common share, for the quarter ended June 30, 2025. Outstanding Shares As of June 30, 2026, the Company had 197.6 million common shares issued and outstanding, as well as 8.6 million stock options and unvested restricted stock units outstanding. About Imdusiran (AB-729) Imdusiran is an RNAi therapeutic specifically designed to reduce all hepatitis B viral proteins and antigens, including hepatitis B surface antigen (“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 delivery technology enabling subcutaneous delivery. In Arbutus’ Phase 2a clinical trials, eight patients with cHBV achieved functional cure following treatment with imdusiran and nucleos(t)ide analogue (“NA”) therapy in combination with either pegylated interferon alfa-2a or low dose nivolumab plus an immunotherapeutic, with six out of the eight patients continuing to sustain functional cure for over two years. An additional 41 patients across the Company’s Phase 2a clinical trials were able to remain off NA therapy for at least 48 weeks during their Phase 2a clinical trials following treatment with imdusiran. Two additional patients who discontinued NA therapy in their Phase 2a clinical trials have now achieved functional cure during their participation in long-term follow-up. Functional cure is defined as sustained HBsAg seroclearance and hepatitis B virus deoxyribonucleic acid (“HBV DNA”) less than the lower limit of quantification after 24 weeks off treatment, with or without anti-hepatitis B surface antibodies. Clinical data generated thus far has shown imdusiran to be generally safe and well-tolerated, while also providing meaningful reductions in HBsAg and HBV DNA. About HBV Hepatitis B is a potentially life-threatening liver infection caused by hepatitis B virus (“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. About Arbutus 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, to protect and defend its intellectual property, which is the subject of on-going lawsuits against Pfizer/BioNTech for use of Arbutus’ patented LNP technology in their COVID-19 vaccines. For more information, visit www.arbutusbio.com. Forward-Looking Statements and Information 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 Company’s expectation to return capital to shareholders, including the expected form and timing thereof; the Company’s receipt of a dividend from Genevant, and the timing thereof; 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; the potential for regulatory approval of Arbutus’ product candidates, Arbutus’ pipeline and development plans for its cHBV programs; and Arbutus’ plans with respect to ongoing patent litigation matters, including 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: the risk that the Company may not receive the expected dividend from Genevant on the terms or within the time expected; the Company may determine not to proceed with a return of capital to shareholders for any reason; 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; 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 at www.sedarplus.ca and at www.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. CONTACT: Arbutus Biopharma Corporation / [email protected]

Q1 total revenue of $179.1M includes estimated license revenue from Genevant related to litigation settlement with Moderna Strong financial position with cash, cash equivalents and marketable securities of $95.2M as of March 31, 2026 FDA granted Fast Track designation to imdusiran, which has the potential to facilitate development and accelerate FDA review WARMINSTER, Pa., May 13, 2026 (GLOBE NEWSWIRE) -- Arbutus Biopharma Corporation (Nasdaq: ABUS) (“Arbutus” or the “Company”), a clinical-stage biopharmaceutical company focused on infectious disease, today reported first quarter 2026 financial results and provided a corporate update. LNP Litigation On March 3, 2026, Arbutus, along with its exclusive licensee, Genevant Sciences (“Genevant”), entered into a settlement agreement to resolve all global patent infringement litigation and patent revocation proceedings involving Moderna. As part of the settlement, Moderna will pay Arbutus and Genevant $950 million upfront in July 2026 (the “Noncontingent Settlement Payment”) and an additional $1.3 billion contingent upon an appellate ruling that 28 U.S.C. §1498 does not bar Arbutus’ and Genevant’s claims against Moderna for patent infringement, except as to doses characterized by the district court as having gone to U.S. government employees. Under the Company’s license with Genevant, the Company expects to receive in July 2026 an estimated $178.7 million of the Noncontingent Settlement Payment, which includes reimbursement of the Company’s litigation costs. In addition, the Company owns approximately 16% of the outstanding common equity of Genevant. For more information about the terms and conditions of the settlement with Moderna, including the contingent payment, please refer to Arbutus’ Quarterly Report on Form 10-Q to be filed with the SEC on May 13, 2026 and Annual Report on Form 10-K filed with the SEC on March 23, 2026. Corporate Updates In April 2026, the U.S. Food and Drug Administration (“FDA”) granted Fast Track designation for imdusiran for the treatment of chronic hepatitis B. The FDA’s Fast Track program is designed to facilitate the development and expedite the review of investigational therapies to treat serious conditions with unmet medical need. A drug granted Fast Track designation may be eligible for several benefits, including earlier and more frequent meetings and communications with the FDA and the potential for rolling review of its application. If relevant criteria are met, investigational therapies that receive Fast Track designation may also qualify for Accelerated Approval or Priority Review of a Biologics License Application or New Drug Application. Financial Results Cash, Cash Equivalents and Investments As of March 31, 2026, the Company had cash, cash equivalents and investments in marketable securities of $95.2 million compared to $91.5 million as of December 31, 2025. During the three months ended March 31, 2026, the Company used $8.1 million in operating activities, which included one-time payments related to its restructuring efforts, and received $11.5 million of proceeds from the exercise of stock options. Revenue Total revenue was $179.1 million for the quarter ended March 31, 2026, compared to $1.8 million for the same period in 2025. The increase of $177.4 million was due to license revenue from Genevant related to the Company’s portion of the Noncontingent Settlement Payment. Operating Expenses Research and development expenses were $4.1 million for the quarter ended March 31, 2026, compared to $9.0 million for the same period in 2025. The decrease of $4.8 million was due primarily to cost savings from the Company’s decisions to reduce its workforce and discontinue in-house scientific research, as well as lower clinical trial costs as studies neared completion. General and administrative expenses were $5.9 million for the quarter ended March 31, 2026, compared to $5.8 million for the same period in 2025. This increase was due primarily to higher legal fees driven by the settlement with Moderna, partially offset by cost-cutting efforts by the Company, which drove reductions in employee compensation-related expenses. There were no restructuring costs in the quarter ended March 31, 2026, compared to $12.4 million for the same period in 2025. Net Income/Loss For the quarter ended March 31, 2026, the Company’s net income was $169.7 million, or income of $0.88 per basic and $0.87 per diluted common share, as compared to a net loss of $24.5 million, or a loss of $0.13 per basic and diluted common share, for the quarter ended March 31, 2025. Outstanding Shares As of March 31, 2026, the Company had 196.9 million common shares issued and outstanding, as well as 9.7 million stock options and unvested restricted stock units outstanding. About Imdusiran (AB-729) Imdusiran is an RNAi therapeutic specifically designed to reduce all hepatitis B viral proteins and antigens, including hepatitis B surface antigen (“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 delivery technology enabling subcutaneous delivery. In Arbutus’ Phase 2a clinical trials, eight patients with chronic hepatitis B (“cHBV”) achieved functional cure following treatment with imdusiran and nucleos(t)ide analogue (“NA”) therapy in combination with either pegylated interferon alfa-2a or low dose nivolumab plus an immunotherapeutic, with six out of the eight patients continuing to sustain functional cure for over two years. An additional 41 patients across the Company’s Phase 2a clinical trials were able to remain off NA therapy for at least 48 weeks during their Phase 2a clinical trials following treatment with imdusiran. Two additional patients who discontinued NA therapy in their Phase 2a clinical trials have now achieved functional cure during their participation in long-term follow-up. Functional cure is defined as sustained HBsAg seroclearance and hepatitis B virus deoxyribonucleic acid (“HBV DNA”) less than the lower limit of quantification after 24 weeks off treatment, with or without anti-hepatitis B surface antibodies. Clinical data generated thus far has shown imdusiran to be generally safe and well-tolerated, while also providing meaningful reductions in HBsAg and HBV DNA. About HBV Hepatitis B is a potentially life-threatening liver infection caused by hepatitis B virus (“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. About Arbutus 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 an on-going lawsuit against Pfizer/BioNTech for use of Arbutus’ patented LNP technology in their COVID-19 vaccines. For more information, visit www.arbutusbio.com. Forward-Looking Statements and Information 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 Company’s estimated license revenue from Genevant related to the litigation settlement with Moderna, and the timing thereof; the potential of Fast Track designation to facilitate development and accelerate FDA review; 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; the potential for regulatory approval of Arbutus’ product candidates, Arbutus’ pipeline and development plans for its cHBV programs; and Arbutus’ plans with respect to ongoing patent litigation matters, including the expected timing thereof and the settlement of the Moderna litigation. 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 at www.sedar.com and at www.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. CONTACT: Arbutus Biopharma Corporation [email protected]

Strong financial position with cash, cash equivalents and marketable securities of $91.5M as of December 2025 $2.25B Moderna global settlement for infringement of lipid nanoparticle (LNP) delivery technology represents significant outcome for Arbutus and Genevant Two additional patients from Phase 2a clinical trials of imdusiran achieve functional cure Milestone payment received under Alnylam LNP license for product candidate to treat hepatocellular carcinoma (HCC) WARMINSTER, Pa., March 23, 2026 (GLOBE NEWSWIRE) -- Arbutus Biopharma Corporation (Nasdaq: ABUS) (“Arbutus” or the “Company”), a clinical-stage biopharmaceutical company focused on infectious disease, today reported fourth quarter and year end 2025 financial results and provided a corporate update. “We delivered another strong quarter, maintaining a disciplined approach to capital allocation and a continued focus on maximizing our cash runway,” said Lindsay Androski, President and CEO of Arbutus. “I am thrilled to announce that two additional patients from our Phase 2a trials of imdusiran have achieved functional cure in chronic hepatitis B (“cHBV”), and am pleased with our team’s continuing progress on our cHBV programs.” LNP Litigation On March 3, 2026, Arbutus, along with its exclusive licensee, Genevant Sciences (“Genevant”), entered into a settlement agreement to resolve all global patent infringement litigation and patent revocation proceedings involving Moderna. As part of the settlement, Moderna will pay Arbutus and Genevant $950 million upfront in July 2026 (“Noncontingent Settlement Payment”) and an additional $1.3 billion contingent upon an appellate ruling that 28 U.S.C. §1498 (“Section 1498”) does not bar Arbutus’ and Genevant’s claims against Moderna for patent infringement, except as to doses characterized by the district court as having gone to U.S. government employees. In asserting that defense, Moderna argued that Section 1498 applies such that U.S. taxpayers should assume liability for its infringement of Arbutus’ and Genevant’s patents for sales made under one of its government contracts. Moderna has also consented to entry of a judgment of infringement and of no invalidity of four Arbutus/Genevant patents. For more information about the terms and conditions of the settlement with Moderna, including the contingent payment, please refer to Arbutus’ Annual Report on Form 10-K filed with the SEC on March 20, 2026. Under the Company’s license with Genevant, the Company is entitled to receive, after deduction of litigation costs, 20% of the Noncontingent Settlement Payment. In addition, the Company owns approximately 16% of the outstanding common equity of Genevant. Arbutus continues to consult closely with and support Genevant to protect and defend Arbutus’ intellectual property, which is the subject of an on-going lawsuit against Pfizer/BioNTech. The Company, together with Genevant, is seeking fair compensation for use of Arbutus’ patented lipid nanoparticle (“LNP”) technology that was developed with great effort and at a great expense, and without which Pfizer/BioNTech’s COVID-19 vaccines would not have been successful. The claim construction hearing for the lawsuit against Pfizer/BioNTech occurred in December 2024, and the court issued a claim construction ruling in September 2025, which construed the disputed claim terms in a manner the Company generally considers to be favorable. The parties are awaiting further scheduling in the litigation. Corporate Updates Two additional patients from the Company’s Phase 2a clinical trials of imdusiran achieved functional cure, making a total of 10 patients to date that have achieved functional cure during Phase 2a clinical trials and long-term follow-up. Two of these functionally cured patients seroreverted during long-term follow-up, but remain virally suppressed and off nucleos(t)ide analogue (“NA”) therapy. In December 2025, the Company recognized revenue of $0.5 million following the achievement of a contractual milestone related to Alnylam’s use of the Company’s proprietary LNP technology in an additional product candidate to treat hepatocellular carcinoma (HCC), underscoring the important role the Company’s LNP technology plays in the delivery of nucleic acids to the body. Payment was received in January 2026. In connection with payments the Company expects to receive under the Moderna settlement, the Company is currently evaluating a return of capital to its shareholders in the third quarter of calendar year 2026, following the receipt of its portion of the noncontingent lump sum payment from Moderna. Financial Results Cash, Cash Equivalents and Investments As of December 31, 2025, the Company had cash, cash equivalents and investments in marketable securities of $91.5 million compared to $122.6 million as of December 31, 2024. During the year ended December 31, 2025, the Company used $39.6 million in operating activities, which included one-time payments related to its restructuring efforts. This was partially offset by $5.5 million of proceeds from the exercise of stock options. Revenue Total revenue was $14.1 million for the year ended December 31, 2025, compared to $6.2 million for the same period in 2024. The increase of $7.9 million was due to the recognition of all previously-deferred revenue as a result of the conclusion of the Company’s strategic partnership with Qilu Pharmaceutical, partially offset by a decrease in license royalty revenues due to a decline in Alnylam’s sales of ONPATTRO. Operating Expenses Research and development expenses were $25.2 million for the year ended December 31, 2025, compared to $54.0 million for the same period in 2024. The decrease of $28.8 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 right-sizing the Company’s workforce. General and administrative expenses were $15.9 million for the year ended December 31, 2025, compared to $22.1 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 for the year ended December 31, 2025 were $12.9 million, and all remaining restructuring-related payments are expected to be made by the first quarter of 2026. Net Loss For the year ended December 31, 2025, the Company’s net loss was $33.5 million, or a loss of $0.17 per basic and diluted common share, as compared to a net loss of $69.9 million, or a loss of $0.38 per basic and diluted common share, for the quarter ended December 31, 2024. Outstanding Shares As of December 31, 2025, the Company had 192.5 million common shares issued and outstanding, as well as 14.0 million stock options and unvested restricted stock units outstanding. About Imdusiran (AB-729) Imdusiran is an RNAi therapeutic specifically designed to reduce all hepatitis B viral proteins and antigens, including hepatitis B surface antigen (“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. In Arbutus’ Phase 2a clinical trials, eight patients with cHBV achieved functional cure following treatment with imdusiran and NA therapy in combination with either pegylated interferon alfa-2a or low dose nivolumab plus an immunotherapeutic, with six out of the eight patients continuing to sustain functional cure for over two years. An additional 41 patients across the Company’s Phase 2a clinical trials were able to remain off NA therapy for at least 48 weeks during their Phase 2a clinical trials following treatment with imdusiran. Two additional patients who discontinued NA therapy in their Phase 2a clinical trials have now achieved functional cure during their participation in long-term follow-up. Functional cure is defined as sustained HBsAg seroclearance and hepatitis B virus deoxyribonucleic acid (“HBV DNA”) less than the lower limit of quantification after 24 weeks off treatment, with or without anti-hepatitis B surface antibodies. Clinical data generated thus far has shown imdusiran to be generally safe and well-tolerated, while also providing meaningful reductions in HBsAg and HBV DNA. About HBV Hepatitis B is a potentially life-threatening liver infection caused by hepatitis B virus (“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. About Arbutus 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’ patented LNP technology in their COVID-19 vaccines. For more information, visit www.arbutusbio.com. Forward-Looking Statements and Information 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; Arbutus’ plans with respect to ongoing patent litigation matters, including the expected timing thereof and the settlement of the Moderna litigation; and Arbutus’ evaluation of a potential return of capital to its shareholders. 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 at www.sedar.com and at www.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. CONTACT: Arbutus Biopharma Corporation / [email protected]

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.” LNP Litigation Arbutus continues to consult closely with and support its exclusive licensee, Genevant Sciences, to protect and defend Arbutus’s intellectual property, which is the subject of on-going lawsuits against Moderna and Pfizer/BioNTech. The Company, together with Genevant, is seeking fair compensation for Moderna’s and Pfizer/BioNTech’s use of Arbutus’s patented LNP technology that was developed with great effort and at a great expense, and without which Moderna’s and Pfizer/BioNTech’s COVID-19 vaccines would not have been successful. In the Moderna U.S. litigation, fact discovery, expert discovery and summary judgment briefing have been completed. A jury trial is scheduled for March 2026. In March 2025, the Company, alongside Genevant Sciences, filed five international lawsuits against Moderna and its affiliates seeking to enforce patents protecting the Company’s patented LNP technology across 30 countries. Public oral hearings for two of the five cases which are before the Unified Patent Court are scheduled for May 2026, and a trial in the Canadian case is set to begin in September 2027. The claim construction hearing for the lawsuit against Pfizer/BioNTech occurred in December 2024, and the court issued a claim construction ruling in September 2025, which construed the disputed claim terms in a manner the Company generally considers to be favorable. Corporate Updates The Company showcased four poster presentations featuring data from its hepatitis B virus (HBV) programs at AASLD 2025. One poster presented new analysis from the Company’s IM-PROVE I Phase 2a clinical trial showing beneficial clinical outcomes were observed across all evaluated HBV genotypes (A to E). The Company also had a Poster of Distinction highlighting AB-101’s maximal PD-L1 receptor occupancy between 68-100% at a 30mg daily dose. Today, the Company published an updated Corporate Presentation on its website, which includes the results of its recently completed analysis of imdusiran clinical data. In addition to the eight functional cures, an additional 40 patients across all cohorts in its Phase 2a trials met study-defined criteria for nucleos(t)ide analogue (NA) therapy discontinuation. In total, 46% (48/105) of all Phase 2a patients either achieved functional cure or remained off NA therapy for at least 48 weeks after discontinuing NA therapy following treatment with imdusiran. Eighteen patients consented to long-term follow-up, including all functionally cured patients and 10 patients who discontinued NA therapy. To date, 94% of those follow-up patients have remained off all treatment for between 58 to 109 weeks. One functionally cured patient seroreverted but remains virally suppressed and off all treatment. Additionally, 56% (5/9) of Phase 1b patients (only received imdusiran and NA therapy) who elected to discontinue NA therapy, remained off all treatment for at least 3 years. Imdusiran has also demonstrated steep and durable declines in HBV DNA, and, with NA therapy, achieved full HBV DNA suppression significantly faster than NA therapy alone. By week 18 of treatment with imdusiran and NA therapy, 100% of Phase 1b HBV DNA positive patients achieved HBV DNA levels below the level of quantification, The eight Phase 2a patients who achieved functional cure continue to have HBV DNA levels below the level of quantification. In 30 hepatitis B e-antigen (HBeAg) positive patients in our Phase 1 and 2a trials, HBeAg decreased in all patients in a dose-dependent manner. Financial Results Cash, Cash Equivalents and Investments 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. Revenue 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. Operating Expenses 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. Net Loss 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. Outstanding Shares 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. About Imdusiran (AB-729) 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. About HBV 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. About Arbutus 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, visit www.arbutusbio.com. Forward-Looking Statements and Information 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 at www.sedar.com and at www.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. CONTACT: Arbutus Biopharma Corporation / [email protected]

Arbutus Biopharma (ABUS) came out with quarterly earnings of $0.01 per share, beating the Zacks Consensus Estimate of a loss of $0.02 per share. This compares to a loss of $0.11 per share a year ago. These figures are adjusted for non-recurring items. This quarterly report represents an earnings surprise of +150.00%. A quarter ago, it was expected that this biopharmaceutical company would post a loss of $0.09 per share when it actually produced a loss of $0.13, delivering a surprise of -44.44%. Over the last four quarters, the company has surpassed consensus EPS estimates two times. Arbutus, which belongs to the Zacks Medical - Biomedical and Genetics industry, posted revenues of $10.74 million for the quarter ended June 2025, surpassing the Zacks Consensus Estimate by 496.61%. This compares to year-ago revenues of $1.73 million. The company has topped consensus revenue estimates three times over the last four quarters. The sustainability of the stock's immediate price movement based on the recently-released numbers and future earnings expectations will mostly depend on management's commentary on the earnings call. Arbutus shares have added about 4.3% since the beginning of the year versus the S&P 500's gain of 7.1%. While Arbutus has underperformed the market so far this year, the question that comes to investors' minds is: what's next for the stock? There are no easy answers to this key question, but one reliable measure that can help investors address this is the company's earnings outlook. Not only does this include current consensus earnings expectations for the coming quarter(s), but also how these expectations have changed lately. Empirical research shows a strong correlation between near-term stock movements and trends in earnings estimate revisions. Investors can track such revisions by themselves or rely on a tried-and-tested rating tool like the Zacks Rank, which has an impressive track record of harnessing the power of earnings estimate revisions. Ahead of this earnings release, the estimate revisions trend for Arbutus was mixed. While the magnitude and direction of estimate revisions could change following the company's just-released earnings report, the current status translates into a Zacks Rank #3 (Hold) for the stock. So, the shares are expected to perform in line with the market in the near future. You can see the complete list of today's Zacks #1 Rank (Strong Buy) stocks here. It will be interesting to see how estimates for the coming quarters and the current fiscal year change in the days ahead. The current consensus EPS estimate is -$0.02 on $1.8 million in revenues for the coming quarter and -$0.23 on $5.85 million in revenues for the current fiscal year. Investors should be mindful of the fact that the outlook for the industry can have a material impact on the performance of the stock as well. In terms of the Zacks Industry Rank, Medical - Biomedical and Genetics is currently in the bottom 42% of the 250 plus Zacks industries. Our research shows that the top 50% of the Zacks-ranked industries outperform the bottom 50% by a factor of more than 2 to 1. CG Oncology, Inc. (CGON), another stock in the same industry, has yet to report results for the quarter ended June 2025. This company is expected to post quarterly loss of $0.49 per share in its upcoming report, which represents a year-over-year change of -75%. The consensus EPS estimate for the quarter has remained unchanged over the last 30 days. CG Oncology, Inc.'s revenues are expected to be $0.33 million, up 195.5% from the year-ago quarter. Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report Arbutus Biopharma Corporation (ABUS) : Free Stock Analysis Report CG Oncology, Inc. (CGON) : Free Stock Analysis Report This article originally published on Zacks Investment Research (zacks.com). Zacks Investment Research

Q2 total revenue of $10.7M includes previously-deferred revenue following reacquisition of Greater China rights to imdusiran Dr. Roger Sawhney joins the Arbutus Board of Directors following resignation of Anuj Hasija Dr. Harry Janssen joins the Arbutus Scientific Advisory Board Strong financial position with cash, cash equivalents and marketable securities of $98.1M WARMINSTER, Pa., Aug. 06, 2025 (GLOBE NEWSWIRE) -- Arbutus Biopharma Corporation (Nasdaq: ABUS) (“Arbutus” or the “Company”), a clinical-stage biopharmaceutical company focused on infectious disease, today reported second quarter 2025 financial results and provided a corporate update. “We delivered a strong quarter, marked by positive quarterly earnings resulting from the conclusion of our Greater China partnership with Qilu,” said Lindsay Androski, President and CEO of Arbutus. “Once again holding global rights for imdusiran, and launching a late-stage clinically focused Scientific Advisory Board, were two important steps taken this quarter in our quest to drive long-term value through our chronic hepatitis B virus (cHBV) programs.” “I am excited to announce that Dr. Harry Janssen of Erasmus MC in Rotterdam has joined our Scientific Advisory Board, bringing his unparalleled knowledge and experience in late-stage clinical trials in cHBV,” Ms. Androski continued. “Today, the Company also congratulates Anuj Hasija on his appointment as Vice President, Global Commercial Strategy for Type 1 Diabetes at Vertex. Anuj has stepped down from the Arbutus Board in order to focus exclusively on this new role, and on behalf of the Company and the entire Board, I thank Anuj for his service. We are also excited to welcome Dr. Roger Sawhney as the newest member of our Board. Dr. Sawhney has enjoyed a distinguished career spanning senior executive roles in biotech, pharma and investing, and also brings extensive public company board experience.” LNP Litigation Arbutus continues to consult closely with and support our exclusive licensee, Genevant Sciences, to protect and defend Arbutus’s intellectual property, which is the subject of on-going lawsuits against Moderna and Pfizer/BioNTech. The Company, together with Genevant, is seeking fair compensation for Moderna’s and Pfizer/BioNTech’s use of Arbutus’s patented LNP technology that was developed with great effort and at a great expense, and without which Moderna’s and Pfizer/BioNTech’s COVID-19 vaccines would not have been successful. In the Moderna U.S. litigation, fact discovery has been completed, and expert discovery is concluding. The summary judgment phase of the case began in July 2025 and a jury trial is scheduled to be held in March 2026. Additionally, in July 2025, the case was reassigned to a different judge in the same court. In March 2025, the Company, alongside Genevant Sciences, filed five international lawsuits against Moderna and its affiliates seeking to enforce patents protecting the Company’s patented LNP technology across 30 countries. The first major hearings in the international lawsuits are expected in the first half of calendar year 2026. The claim construction hearing for the lawsuit against Pfizer/BioNTech occurred in December 2024. The court has not provided guidance for the timing of its ruling in the claim construction hearing, which could potentially come in 2025. Corporate Updates In June 2025, the Company and Qilu Pharmaceutical mutually agreed to conclude the strategic partnership for the development, manufacturing, and commercialization of imdusiran in Greater China. The Company now once again holds global rights for its lead compound, imdusiran. Dr. Harry L.A. Janssen, MD, PhD, joined the Company’s Scientific Advisory Board effective August 1, 2025, increasing the membership to six global experts in cHBV treatment. Dr. Janssen is a Professor of Hepatology and the Chair of the Department of Gastroenterology and Hepatology at Erasmus MC, Rotterdam, The Netherlands. Effective August 4, 2025, Anuj Hasija resigned from the Company’s Board of Directors due to his transition to a full-time executive role that precludes his participation on the Arbutus and other boards of directors. Filling the vacancy on our Board of Directors, Dr. Roger Sawhney, MD, joined the Board effective August 4, 2025. Dr. Sawhney is a seasoned executive and board member with extensive experience across biotechnology, pharmaceuticals, healthcare technology, and investment sectors. He holds an MD from Harvard Medical School and a BA in Economics from Stanford University. Financial Results Cash, Cash Equivalents and Investments As of June 30, 2025, the Company had cash, cash equivalents and investments in marketable securities of $98.1 million compared to $122.6 million as of December 31, 2024. During the six months ended June 30, 2025, the Company used $29.1 million in operating activities, which included one-time payments related to our restructuring efforts. This was partially offset by $3.1 million of proceeds from the exercise of employee stock options. Revenue Total revenue was $10.7 million for the quarter ended June 30, 2025, compared to $1.7 million for the same period in 2024. The increase of $9.0 million was primarily due to the recognition of all previously-deferred revenue as a result of the conclusion of the Company’s strategic partnership with Qilu Pharmaceutical, partially offset by a decrease in license royalty revenues due to a decline in Alnylam’s sales of ONPATTRO. Operating Expenses Research and development expenses were $5.5 million for the quarter ended June 30, 2025 compared to $15.6 million for the same period in 2024. The decrease of $10.1 million was due primarily to cost savings from the Company’s decision in August 2024 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 $3.3 million for the quarter ended June 30, 2025, compared to $7.5 million for the same period in 2024. This decrease was due primarily to cost cutting efforts by the Company, which drove reductions in litigation-related legal fees and employee compensation-related expenses. Restructuring costs in the quarter ended June 30, 2025 were $0.2 million, and all remaining restructuring-related payments are expected to be made in the second half of 2025. Net Income/Loss For the quarter ended June 30, 2025, the Company’s net income was $2.5 million, or income of $0.01 per basic and diluted common share, as compared to a net loss of $19.8 million, or a loss of $0.11 per basic and diluted common share, for the quarter ended June 30, 2024. Outstanding Shares As of June 30, 2025, the Company had 191.6 million common shares issued and outstanding, as well as 15.2 million stock options and unvested restricted stock units outstanding. About Imdusiran (AB-729) 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. 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. About HBV Hepatitis B is a potentially life-threatening liver infection caused by the hepatitis B virus (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. About Arbutus 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, visit www.arbutusbio.com. Forward-Looking Statements and Information 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; 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 at www.sedar.com and at www.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. CONTACT: Arbutus Biopharma Corporation / [email protected]