Arbutus Biopharma Corp

Patent Infringement Litigation vs. Pfizer and BioNTech

In April 2023, we and Genevant filed a lawsuit in the United States District Court for the District of New Jersey against Pfizer/BioNTech seeking damages for infringement of United States Patent Nos. 9,504,651; 8,492,359; 11,141,378; 11,298,320; and 11,318,098 in the manufacture and sale of any COVID-19 mRNA-LNP vaccines. The patents relate to nucleic acid-lipid particles and their composition, manufacture, delivery and methods of use. In the lawsuit, we seek fair compensation for Pfizer’s and BioNTech’s use of our patented technology that was developed with great effort and at great expense, without which their COVID-19 mRNA-LNP vaccines would not have been successful. The claim construction hearing occurred in December 2024, and in September 2025, the court issued a claim construction ruling, which construed the disputed claim terms in a manner we generally consider to be favorable. Fact discovery is ongoing and a final pretrial conference is scheduled for November 2027. The parties are awaiting a trial date in the litigation.

In July 2026 and November 2026, we, along with Genevant, filed multiple international lawsuits seeking to enforce patents protecting our LNP technology against Pfizer/BioNTech and certain of their affiliates. We and Genevant are seeking monetary relief, as well as injunctions against Pfizer/BioNTech’s COVID-19 mRNA-LNP vaccines and any other products that would infringe the asserted patents.

The international lawsuits are as follows:

•Canada: Federal Court of Canada File No. T-3200-26, seeking a permanent injunction and damages or, if Arbutus and Genevant elect, an accounting of Pfizer/BioNTech’s profits, attributable to infringement of Canadian Patent Nos. 2,721,333 and 2,767,127

•Unified Patent Court (UPC): Case UPC-CFI-0002562/2026, seeking permanent injunctions, as well as monetary damages, which can include recovery of Pfizer/BioNTech’s unfair profits from infringement of EP 4 241 767

•UPC: Case UPC-CFI-0002566/2026, seeking permanent injunctions, as well as monetary damages, which can include recovery of Pfizer/BioNTech’s unfair profits from infringement of EP 4 495 237

•Japan: Tokyo District Court Case seeking a permanent injunction and damages for infringement of Japanese Patent No. 5,475,753.

•Japan: Tokyo District Court Case seeking a permanent injunction and damages for infringement of Japanese Patent No. 7,936,499.

The UPC actions seek relief for infringing activities by Pfizer/BioNTech and certain of their affiliates in Austria, Belgium, Bulgaria, Denmark, Estonia, Finland, France, Germany, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Poland, Portugal, Romania, Slovenia, Spain, and Sweden.

Patent Infringement Litigation vs. Moderna

In February 2022, we and Genevant filed a lawsuit in the United States District Court for the District of Delaware against Moderna seeking damages for infringement of United States Patent Nos. 8,058,069, 8,492,359, 8,822,668, 9,364,435, 9,504,651, and 11,141,378 in the manufacture and sale of MRNA-1273, Moderna’s vaccine for COVID-19. In March 2025, we and Genevant filed five international lawsuits against Moderna seeking to enforce patents protecting our patented LNP technology. Together, these lawsuits comprise the Moderna LNP Litigation.

In March 2026, we and Genevant entered into the Moderna Settlement Agreement with Moderna to resolve the Moderna LNP Litigation. Pursuant to the Moderna Settlement Agreement, all parties filed stipulated judgments and stipulations of dismissal for the respective courts or tribunals to enter judgment, dismiss with prejudice or withdraw (as the case may be) all claims in the Moderna LNP Litigation, except that Moderna was allowed to file the Moderna §1498 Appeal. The Moderna §1498 Appeal is an appeal of the consent judgment entered in the District Court solely with respect to whether §1498 bars our and Genevant’s claims for direct infringement and indirect infringement against Moderna for vaccine doses that were sold to the United States Government under a particular contract and characterized by the District Court as “vaccines that did not go directly to United States Government employees.” On November 5, 2026, expedited oral argument was held at the U.S. Court of Appeals for the Federal Circuit regarding the Moderna §1498 Appeal, and a decision is forthcoming.

Under the terms of the Moderna Settlement Agreement, Moderna made an aggregate $950.0 million Noncontingent Settlement Payment to us and Genevant on July 8, 2026. We received $178.4 million on July 8, 2026 as our share of the Noncontingent Settlement Payment, which included reimbursement of our litigation costs.

In addition, as described in more detail in, and subject to the terms of, the Moderna Settlement Agreement, Moderna will make an additional Contingent Settlement Payment of an aggregate $1.3 billion to us and Genevant (i) if the U.S. Court of Appeals for the Federal Circuit (whether by the initial panel, upon panel rehearing oren banc) affirms, or if there is a final non-appealable judgment that affirms, the rejection of Moderna’s affirmative defense pursuant to §1498 by the District Court in its entirety or otherwise holds that §1498 does not bar our and Genevant’s claim against Moderna as to either or both of direct infringement and indirect infringement with respect to all of the doses subject to the Moderna §1498 Appeal, or (ii) upon a voluntary dismissal of the Moderna §1498 Appeal (any of the foregoing (clause (i) or (ii) above), an Arbutus/Genevant §1498 Victory). If an appellate ruling were to hold that §1498 bars our and Genevant’s infringement claims as to some, but not all, of the doses subject to the Moderna §1498 Appeal, the Moderna Settlement Agreement provides that Moderna will pay us and Genevant a prorated amount of the Contingent Settlement Payment, calculated based on the number of doses for which §1498 bars our and Genevant’s infringement claims as clearly articulated by the Federal Circuit or, if not clearly articulated by the Federal Circuit, as mutually agreed by the parties or determined in an accelerated binding arbitration process.

Under certain circumstances, as described in more detail in, and subject to the terms of, the Moderna Settlement Agreement, if the Arbutus/Genevant §1498 Victory is subsequently overturned in Moderna’s favor in a final nonappealable decision, we and Genevant are required to return any Contingent Settlement Payment to Moderna, plus interest. If, following an Arbutus/Genevant §1498 Victory, either (i) Moderna does not timely appeal such Arbutus/Genevant §1498 Victory or (ii) such Arbutus/Genevant §1498 Victory is subsequently affirmed in a final nonappealable decision, Moderna will have no further right to a potential repayment of the Contingent Settlement Payment.

The Moderna Settlement Agreement includes mutual financial covenants to protect the payment or repayment of the Contingent Settlement Payment, as described above.

The Moderna Settlement Agreement also contains customary mutual releases in favor of each of us/Genevant and Moderna in respect of the Moderna LNP Litigation. In addition, the Moderna Settlement Agreement includes a fully paid-up, royalty free, irrevocable, non-exclusive, worldwide license and covenant not to sue granted to Moderna under any patents and patent applications owned or licensable by us or Genevant or our respective direct and indirect wholly owned subsidiaries that exist, or that claim priority to patents or patent applications that exist, as of the effective date of the Moderna Settlement Agreement, to make, sell and generally otherwise exploit Moderna’s SPIKEVAX™, mNEXSPIKE™ and mRESVIA™ vaccines and any other mRNA vaccines that include a lipid SM-102-based LNP formulation against an infectious disease and meet certain conditions, as well as a covenant not to sue with respect to certain other of our and Genevant’s patents and Moderna products.

In March 2026, we and Genevant filed a complaint against the United States in the United States Court of Federal Claims, seeking to recover compensation for Moderna’s infringement for vaccine doses that were sold to the United States Government under a particular contract and were deemed by the District Court to be doses that were provided directly to United States Government employees. The complaint also includes a protective request to recover compensation from the United States for any other vaccine doses where, as a result of the Moderna §1498 Appeal, §1498 is deemed to bar our and Genevant’s claims for direct infringement and indirect infringement against Moderna.

Moderna and Merck European Oppositions

In April 2018, Moderna and Merck, Sharp & Dohme Corporation (together with its successors and affiliates, Merck) filed Notices of Opposition to our European patent EP 2279254 (the ’254 Patent) with the European Patent Office (EPO), requesting that the ’254 Patent be revoked in its entirety for all contracting states. From 2018 until 2024, various hearings were held by different divisions of the EPO regarding requests submitted by all parties. Oral proceedings were held in June 2024, and the Opposition Division of the EPO upheld the ’254 Patent but declined our and Genevant’s request to broaden certain claims in the ’254 Patent. Both parties appealed the Opposition Division’s decision, and in June 2026, the Board of Appeal of the EPO issued a written decision explaining their earlier verbal revocation of the ’254 Patent. We disagree with the outcome, and we filed a petition for review by the Enlarged Board of Appeal of the EPO in August 2026. A hearing has been scheduled for March 2027. We do not expect the EPO revocation decision to have an impact on the potential outcome, or timing, of our patent infringement litigation pending against Pfizer/BioNTech.

In April 2025, Moderna filed a revocation action on our European patent EP 4241767 (the ’767 patent) with the EPO, requesting that the patent be revoked in its entirety for all contracting states. In July 2025, Merck, Arrowhouse GmbH and Keltie LLP filed three additional revocation actions against the ’767 patent. Initial briefing has been completed and we are currently awaiting an initial hearing date. In March 2026, pursuant to the Moderna Settlement Agreement, Moderna withdrew from this revocation proceeding. In May 2026, we entered into an agreement with Merck (the Merck Agreement) where we, among other things, acknowledged that the Moderna Settlement Agreement covered a vaccine being jointly developed by Moderna and Merck and we agreed not to sue Merck regarding such vaccine, in exchange for Merck withdrawing from the revocation proceeding. In May 2026, pursuant to the Merck Agreement, Merck withdrew from this revocation proceeding.

While we are the patent owner, the ’254 Patent, the ’767 Patent, and the other patents in our LNP portfolio have been licensed to Genevant under the Genevant License.

Other Matters

We are also involved with various legal matters arising in the ordinary course of business. We make provisions for liabilities when it is both probable that a liability has been incurred and the amount of the loss can be reasonably estimated. Such provisions are reviewed at least quarterly and adjusted to reflect the impact of any settlement negotiations, judicial and administrative rulings, advice of legal counsel, and other information and events pertaining to a particular case. Litigation is inherently unpredictable. Although the ultimate resolution of these various matters cannot be determined at this time, we do not believe that such matters, individually or in the aggregate, will have a material adverse effect on our consolidated results of operations, cash flows, or financial condition.