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

Arbutus Biopharma Corp 8-K