Arbutus Biopharma (NASDAQ: ABUS) updates COVID-19 vaccine patent case vs Pfizer

Rhea-AI Filing Summary

Arbutus Biopharma Corporation reported that the U.S. District Court for the District of New Jersey issued a claim construction ruling in its ongoing patent lawsuit against Pfizer Inc. and BioNTech SE. The case, brought by Arbutus and its licensee Genevant Sciences, seeks damages for alleged infringement of several U.S. patents related to the manufacture and sale of Pfizer/BioNTech’s COVID-19 mRNA-based vaccines. The court’s detailed claim construction order and opinion, dated September 9, 2025, have been filed as an exhibit to this report, providing the interpretations that will guide how the patent claims are applied as the litigation continues.

Insights

Biotech litigation and IP analyst

Key claim terms in Arbutus’s COVID-19 vaccine patent suit are now judicially defined.

The disclosure centers on a claim construction ruling in Arbutus’s patent case against Pfizer and BioNTech over COVID-19 mRNA-based vaccines. Claim construction determines how specific patent terms are interpreted, which can significantly influence later questions of infringement and validity. The report notes that the court issued its order and opinion on September 9, 2025 and that these materials are attached as an exhibit.

The impact depends on whether the court adopted broader or narrower readings of Arbutus’s asserted claims, but those details are contained in the referenced order, not summarized here. At this stage there is no disclosed damages figure or timeline shift, only that the litigation has reached a key procedural milestone. Subsequent stages, such as summary judgment or trial, will build on these definitions, and later company communications or filings would be needed to understand any financial implications.

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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): September 9, 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 ☐

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

Item 8.01. Other Events.

On September 9, 2025, the U.S. District Court for the District of New Jersey issued a claim construction ruling in the lawsuit brought by Arbutus Biopharma Corporation and its licensee Genevant Sciences against Pfizer Inc. and BioNTech SE (Pfizer/BioNTech) seeking damages for infringement of U.S. Patent Nos. 9,504,561, 8,492,359, 11,141,378, 11,298,320 and 11,318,098 in the manufacture and sale of Pfizer/BioNTech’s COVID-19 mRNA-based vaccines. A copy of the Court’s claim construction order and opinion is filed herewith as Exhibit 99.1 and is incorporated by reference herein.

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits.

Exhibit Number		Description
99.1		Claim Construction Order and Opinion, dated September 9, 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: September 10, 2025	By:	/s/ Tuan Nguyen
	Name:	Tuan Nguyen
	Title:	Chief Financial Officer

FAQ

What legal development did Arbutus Biopharma (ABUS) report in this 8-K?

Arbutus Biopharma reported that the U.S. District Court for the District of New Jersey issued a claim construction ruling in its patent lawsuit involving Pfizer and BioNTech.

Which companies are involved in Arbutus Biopharma (ABUS)'s patent case?

The case is brought by Arbutus Biopharma Corporation and its licensee Genevant Sciences against Pfizer Inc. and BioNTech SE related to COVID-19 mRNA-based vaccines.

What patents are at issue in Arbutus Biopharma (ABUS)'s lawsuit against Pfizer and BioNTech?

The lawsuit concerns alleged infringement of U.S. Patent Nos. 9,504,561, 8,492,359, 11,141,378, 11,298,320 and 11,318,098.

What products are implicated in Arbutus Biopharma (ABUS)'s patent infringement claims?

The claims relate to alleged infringement in the manufacture and sale of Pfizer/BioNTech’s COVID-19 mRNA-based vaccines.

Where can investors find the full claim construction order in the Arbutus (ABUS) filing?

The Claim Construction Order and Opinion dated September 9, 2025 is filed as Exhibit 99.1 and incorporated by reference in the report.

Does this Arbutus Biopharma (ABUS) filing disclose financial impacts from the patent ruling?

The report states that the action is a claim construction ruling in ongoing litigation and that Arbutus and Genevant are seeking damages, but it does not provide specific financial impact details.