UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549
FORM 8-K
CURRENT REPORT
Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934
Date of Report (Date of earliest event reported): December 11, 2025
Arbutus Biopharma Corporation
(Exact name of registrant as specified in its charter)
| British Columbia, Canada | 001-34949 | 98-0597776 | ||
|
(State or other jurisdiction of incorporation) |
(Commission File Number) |
(IRS Employer Identification No.) |
|
701 Veterans Circle Warminster, Pennsylvania |
18974 | |
| (Address of principal executive offices) | (Zip Code) |
(267) 469-0914
(Registrant’s telephone number, including area code)
(Former name or former address, if changed since last report.)
Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:
| ☐ | Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) |
| ☐ | Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) |
| ☐ | Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) |
| ☐ | Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) |
Securities registered pursuant to Section 12(b) of the Act:
| Title of each class | Trading Symbol(s) | Name of each exchange on which registered | ||
| Common Shares, without par value | ABUS | The Nasdaq Stock Market LLC |
Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).
Emerging growth company ☐
Item 8.01. Other Events.
If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. o On December 11, 2025, Lindsay Androski, Chairperson, Chief Executive Officer and President of Arbutus Biopharma Corporation (the “Company”) will give a presentation regarding the Company’s ongoing lawsuits against Moderna Therapeutics, Inc., Pfizer Inc. and BioNTech SE, for their use of the Company’s patented lipid nanoparticle technology in their COVID-19 vaccines (“LNP Litigation”), as part of Roivant Sciences Ltd.’s 2025 Investor Day. The LNP Litigation slides that Ms. Androski will present are filed herewith as Exhibit 99.1 and are incorporated by reference herein.
The LNP Litigation slides contain 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 the LNP Litigation slides include statements about the Company’s plans with respect to the ongoing patent litigation matters, and the expected timing thereof. With respect to the forward-looking statements contained in the LNP Litigation slides, the Company has made numerous assumptions regarding the LNP Litigation. While the Company 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 the Company’s 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 therein. Known risk factors include, among others: 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 the Company’s cash resources for its foreseeable and unforeseeable operating expenses and capital expenditures.
A more complete discussion of the risks and uncertainties facing the Company appears in the Company’s Annual Report on Form 10-K, the Company’s Quarterly Reports on Form 10-Q and the Company’s continuous and periodic disclosure filings, which are available at www.sedar.com and at www.sec.gov. All forward-looking statements in the LNP Litigation slides are qualified in their entirety by this cautionary statement, and the Company 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 in the LNP Litigation slides to reflect future results, events or developments, except as required by law.
Item 9.01. Financial Statements and Exhibits.
(d) Exhibits.
| Exhibit Number | Description | |
| 99.1 | Presentation by Lindsay Androski on December 11, 2025 | |
| 104 | Cover Page Interactive Data File (embedded within the Inline XBRL document) |
SIGNATURE
Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.
| Arbutus Biopharma Corporation | ||
| Date: December 11, 2025 | By: | /s/ Tuan Nguyen |
| Name: | Tuan Nguyen | |
| Title: | Chief Financial Officer | |
Exhibit 99.1

1 Genevant & Arbutus LNP Litigation Lindsay Androski Special Counsel, Genevant CEO, Arbutus Matt Gline CEO, Roivant For investor audiences only Forward - Looking Statements This presentation includes forward - looking statements that are subject to substantial risks and uncertainties that could cause actual results to differ materially from those expressed or implied by such statements.

All statements other than statements of historical facts contained in this presentation, including statements regarding our future results of operations and financial position, business strategy, potential uses of cash and capital allocation, research and development plans, profitability, the anticipated timing, costs, design, conduct and results of our ongoing and planned preclinical studies and clinical trials for our products and product candidates, and any commercial potential of our products and product candidates are forward - looking statements. These forward - looking statements are based upon the current expectations and beliefs of our management as of the date of this presentation and are subject to certain risks and uncertainties that could cause actual results to differ materially from those described in the forward - looking statements. Although we believe that our plans, intentions, expectations and strategies as reflected in or suggested by those forward - looking statements are reasonable, we can give no assurance that the plans, intentions, expectations or strategies will be attained or achieved. Furthermore, actual results may differ materially from those described in the forward - looking statements. These forward - looking statements may be affected by a number of risks, uncertainties and assumptions, including, but not limited to, those risks set forth in the sections captioned “Risk Factors” and “Forward - Looking Statements” of our filings with the U.S. Securities and Exchange Commission, available at www.sec.gov and investor.roivant.com. We operate in a very competitive and rapidly changing environment in which new risks emerge from time to time. These forward - looking statements are based upon the current expectations and beliefs of our management as of the date of this presentation, and are subject to certain risks and uncertainties that could cause actual results to differ materially from those described in the forward - looking statements. Except as required by applicable law, we assume no obligation to update publicly any forward - looking statements, whether as a result of new information, future events or otherwise. Disclaimer This presentation is intended for the investor community only; it is not intended to promote the product candidates referenced herein or otherwise influence healthcare prescribing decisions. 2 For investor audiences only 3 We believe that both the Moderna COVID - 19 vaccine (SPIKEVAX) and Pfizer/BioNTech’s COVID - 19 vaccine (COMIRNATY) infringe multiple Genevant/Arbutus LNP patents In the ex - US Moderna litigation, initial court hearings and rulings are expected in 2026 Markman rulings (claim construction) have been issued in both US cases – viewed by Genevant generally to be favorable Global COVID - 19 vaccine sales since launch have been ~$14 5 BN between Moderna and Pfizer/BioNTech In the US Moderna litigation, a jury trial has been scheduled for March 2026 . Awaiting court scheduling in the Pfizer/BioNTech litigation Key Takeaways: LNP Litigation For investor audiences only Note: All references are to calendar years and are approximate and subject to change. The timing of the litigation - related event s noted above is subject to change, including at the discretion of the court. See Slide 2 for further information on these fo rwa rd - looking statements


For investor audiences only Genevant and Arbutus Corporate History 2006 Protiva acquired Tekmira, another company working on LNP technology Roivant set out to assemble a leading global HBV company by merging OnCore Biopharma with Protiva/Tekmira to form Arbutus Biopharma Roivant and Arbutus launched Genevant as a joint venture to focus on Arbutus’ LNP and ligand conjugate delivery technologies, with Arbutus’ focus remaining on HBV therapeutics 2008 2015 2018 Protiva and Alnylam (an RNAi developer) published a landmark study in Nature demonstrating the first effective gene silencing in monkeys, using Protiva’s LNP technology 2000 Ian MacLachlan co - founded Protiva, which became a pioneer in LNP technology 4 For investor audiences only 5 A Leading Nucleic Acid Delivery Company • Industry - leading LNP delivery capabilities and IP portfolio • Selective collaboration business model, partnering with payload companies to develop innovative nucleic acid medicines • The first LNP technology to be part of an FDA - approved RNA product, Alnylam’s Onpattro ® developed under LNP license from Arbutus


For investor audiences only • Some of the US patents licensed by Genevant from Arbutus include: • Moderna previously sought to invalidate two of the particle composition patents referenced above with IPR challenges but was largely unsuccessful • Litigation is ongoing against Moderna in the US and certain other jurisdictions and against Pfizer/BioNTech in the US to seek appropriate compensation for the unauthorized use of Genevant’s /Arbutus’s patented technology 6 Genevant/Arbutus IP Portfolio and Pending Litigation Expiration Date US Patent No.

Subject Matter April 2029 8,058,069 Particle Composition April 2029 8,492,359 April 2029 8,822,668 April 2029 9,364,435 April 2029 11,141,378 July 2023 9,504,651 mRNA - LNP Compositions June 2023 11,298,320 Manufacturing Methods June 2023 11,318,098 For investor audiences only 7 mRNA COVID - 19 Vaccines from Moderna and Pfizer/BioNTech Have Generated Over $145BN in Revenue Revenue as of 9/30/2025 Data and sales calculated from Evaluate and company docs from MRNA, PFE, and BNTX • Total SpikeVax Sales account for ~1/3 of mRNA vaccine sales to date; Comirnaty sales account for remaining ~2/3 • US SpikeVax Sales make up ~10% of global COVID - mRNA vaccine sales to date • Genevant /ABUS continue to pursue recovery against Pfizer and BioNTech in the US, as well as against Moderna in the US and in several other major markets $14 $33 $22 $76 MRNA and PFE/BNTX COVID - 19 Vaccine Sales ($ BNs) SpikeVax US SpikeVax Ex-US Comirnaty US Comirnaty Ex-US For investor audiences only 9 In February 2022, Genevant and Arbutus Jointly Filed a Complaint Against Moderna Asserting Patent Infringement on Patents Related to LNP Technology Case filed in the US District Court for the District of Delaware asserting infringement of six patents Genevant and Arbutus did not seek an injunction or otherwise to impede the sale, manufacture, or distribution of Moderna’s COVID - 19 vaccine, given the unprecedented global emergency We recognize the important work of Moderna that helped lead to a lifesaving vaccine in record time That success was built on, and made possible by, the substantial advances and contributions of Arbutus and Genevant scientists, which Moderna utilized extensively well before COVID - 19 The filing of this lawsuit was necessary because Moderna did not pursue and obtain a license to Genevant’s LNP technology for COVID - 19

Moderna Case


For investor audiences only 10 Moderna Patent Litigation Timeline: Years in the Making Note: All references are to calendar years and are approximate and subject to change. The timing of the litigation - related event s noted above is subject to change, including at the discretion of the court. See Slide 2 for further information on these fo rwa rd - looking statements Early 2023 The U.S. DOJ filed a Statement of Interest in support of MRNA; Court reaffirmed Nov 2022 decision Feb 2022 Genevant and Arbutus jointly filed a complaint against MRNA 2025 Initiated international proceedings against MRNA; discovery and summary judgment briefing concluded in US. Jan 2026 Pretrial submissions due Early 2024 Court issued a Markman ruling construing disputed patent terms Nov 2022 Court denied MRNA’s partial motion to dismiss based on Section 1498 (which would shift liability to U.S. taxpayers) March 2026 Jury trial scheduled (~2 weeks) 2026 First international hearings in ex - US cases For investor audiences only 11 Summary Judgment Motions Filed in US Moderna Case Note: All references are to calendar years and are approximate and subject to change.

The timing of the litigation - related event s noted above is subject to change, including at the discretion of the court. See Slide 2 for further information on these fo rwa rd - looking statements Genevant and Arbutus Filed 5 Motions for Summary Judgment 1. Moderna cannot relitigate obviousness arguments against the Lipid Composition Patents (the ’359, ’435, and ’378 patents) already raised in its unsuccessful IPRs and appeals. 2. Moderna cannot argue at trial that the Asserted Patents are invalid because they do not enable someone in the art to practice the inventions without undue experimentation. 3. Arbutus and Genevant did not derive the invention disclosed in the ’651 patent from a much later Moderna invention. 4. 28 U.S.C. § 1498 does not apply (cross motion). 5. Moderna’s indefiniteness arguments fail as a matter of law (cross motion). Moderna Filed 3 Motions for Summary Judgment 1. 28 U.S.C. § 1498 requires Arbutus and Genevant to recover damages for infringement under one government contract from the U.S. government, not Moderna. 2. Plaintiffs’ claims under the doctrine of equivalents are barred by amendments and arguments made to the PTO during patent prosecution, and Arbutus and Genevant should be able to recover for literal infringement only. 3. The asserted claims of the ’651 patent are invalid for indefiniteness with respect to the Court’s construction of the term “fully encapsulated.” Patents Remaining to Be Litigated at Trial (Following Judge’s Order on Claim Narrowing) US Patent No.


Subject Matter 8,492,359 Particle Composition 9,364,435 11,141,378 9,504,651 mRNA - LNP Compositions For investor audiences only 12 Moderna’s Motions to Exclude Genevant/Arbutus’ Expert Testimony 1) Damages methodologies 2) Opinions regarding willful infringement 3) Fractionation testing 4) Opinions regarding infringement 5) Opinions regarding applicability of Section 1498 Genevant/Arbutus’ Motions to Exclude Moderna’s Expert Testimony 1) Damages methodologies 2) Certain opinions regarding Infringement, Doctrine of Equivalents, Written Description and Enablement 3) Opinions regarding obviousness Daubert Motions; Judge to Decide Admissibility of Certain Expert Testimony For investor audiences only Key Upcoming Milestones in US Litigation • Judge to rule on summary judgment motions, including decision on § 1498, before the jury trial in March • Judge will rule on Daubert motions, which could narrow the expert testimony allowed to be presented on both sides or impact presentations on damages, infringement, willful infringement, and invalidity • A jury trial is currently scheduled to start on March 9, 2026, in the U.S. District Court of Delaware. Jury selection will occur that day • Genevant and Arbutus first, and Moderna second, will present their cases over the course of ~2 weeks • Jury will deliberate, and parties will remain in Delaware until the jury issues their verdict Jury Trial Summary Judgement/Daubert Motions • Any jury verdict is expected to be appealed • Post - trial motions entertained by trial court in period after trial • An appeal could take an additional 18 - 24 months • If the jury rules favorably for Genevant/Arbutus, to obtain a stay of execution of judgment pending appeal, Moderna would likely need to obtain a bond or post cash collateral with the court within 30 days After the Trial 13 Note: All references are to calendar years and are approximate and subject to change. The timing of the litigation - related event s noted above is subject to change, including at the discretion of the court.

See Slide 2 for further information on these fo rwa rd - looking statements For investor audiences only 14 Overview of International Infringement Litigation; Accounts for Significant Portion of Ex - US SpikeVax Revenue All ex - US jurisdictions with cases pending bifurcate liability from damages and, with success in liability phase, typically issue injunction preventing future sales; many award damages based on profits rather than reasonable royalty Initial Hearings Expected in 2026 Initial Hearings Expected in 2027 UPC Japan Switzerland Canada Note: All references are to calendar years and are approximate and subject to change. The timing of the litigation - related event s noted above is subject to change, including at the discretion of the court. See Slide 2 for further information on these fo rwa rd - looking statements For investor audiences only 16 Pfizer/BioNTech Litigation Timeline to Date Note: All references are to calendar years and are approximate and subject to change.

Pfizer Case

The timing of the litigation - related event s noted above is subject to change, including at the discretion of the court. See Slide 2 for further information on these fo rwa rd - looking statements Awaiting Court scheduling on future deadlines TBD The Court held a Markman hearing to construe disputed terms within the claims of the asserted patents Dec 2024 Now Fact discovery is currently ongoing BioNTech license agreement to Genevant LNP Technology for certain targets (non - COVID) 2018 The Court issued its ruling and construed disputed claim terms in a manner that Genevant considers generally favorable Sep 2025 Genevant/ABUS jointly filed a complaint against Pfizer/BioNTech in the US District Court for the District of New Jersey asserting infringement of five patents Apr 2023 For investor audiences only Publicly Available Evidence Supports the Initial Filing of Our Case Publicly Available Evidence Supporting the Case 1 • BioNTech had license to Genevant LNP Technology for use for specific cancer and rare liver disease targets dating back to 2018; contract described Genevant’s platform as “the best lipid nanoparticle technology” • FDA EUA filing indicated that Pfizer/BioNTech’s mRNA - vaccine infringes on Genevant and Arbutus lipid composition patents ‘651, ‘359 and ‘378 • CNN report covering Pfizer’s manufacturing process confirmed infringement of Genevant and Arbutus manufacturing patents ‘320 and ‘098 17 “T - Mixer” used to create LNP; Arbutus/Genevant ‘320 patent Note: Case 3:23 - cv - 01876 - ZNQ - TJB, Document 1; COMPLAINT FOR PATENT INFRINGEMENT (2022)


For investor audiences only 18 In Summary: LNP Litigation We believe both Moderna’s and Pfizer/BioNTech’s COVID - 19 vaccines infringe multiple Genevant/Arbutus patents Trial/hearings in both the US and the ex - US litigation against Moderna expected in 2026 Awaiting court scheduling in the Pfizer/BioNTech litigation Markman decisions in both cases viewed by Genevant generally to be favorable For investor audiences only Note: All references are to calendar years and are approximate and subject to change. The timing of the litigation - related event s noted above is subject to change, including at the discretion of the court. See Slide 2 for further information on these fo rwa rd - looking statements For investor audiences only 19 We believe that both the Moderna COVID - 19 vaccine (SPIKEVAX) and Pfizer/BioNTech

’s COVID - 19 vaccine (COMIRNATY) infringe multiple Genevant/Arbutus LNP patents In the ex - US Moderna litigation, initial court hearings and rulings are expected in 2026 Markman rulings (claim construction) have been issued in both US cases – viewed by Genevant generally to be favorable Global COVID - 19 vaccine sales since launch have been ~$14 5 BN between Moderna and Pfizer/BioNTech In the US Moderna litigation, a jury trial has been scheduled for March 2026 . Awaiting court scheduling in the Pfizer/BioNTech litigation Key Takeaways: LNP Litigation For investor audiences only