Arbutus Biopharma Corporation

Issuer

Arbutus Biopharma Corp

Security title

Common Shares, without par value

Principal address

Comment

EXPLANATORY NOTE Pursuant to Rule 13d-2 of the Securities Exchange Act of 1934, as amended, this Amendment No. 14 ("Amendment No. 14") amends certain items of the Schedule 13D filed with the Securities and Exchange Commission (the "SEC") on March 16, 2015, as amended by Amendments No. 1 through 13, previously filed with the SEC (the "Schedule 13D") relating to the Common Shares, without par value (the "Common Shares"), of Arbutus Biopharma Corporation (the "Issuer"), which are beneficially owned by Roivant Sciences Ltd. ("Roivant" or the "Reporting Person"). This Amendment No. 14 amends the Original Schedule 13D on behalf of the Reporting Person to furnish the information set forth herein. Except as set forth below, all Items of the Original Schedule 13D remain unchanged. All capitalized terms contained herein but not otherwise defined shall have the meanings ascribed to such terms in the Original Schedule 13D.

Filing person

Item 2 is hereby amended solely to restate the list of Covered Persons in Item 2(a) of the Schedule 13D with those listed on Exhibit 99.1 hereto, which Exhibit 99.1 is incorporated into this Item 2 by reference.

Purpose of transaction

Item 4 is hereby amended by adding the following to the end thereof: On August 24, 2026, the Issuer commenced a modified Dutch auction tender offer to purchase for cancellation up to US$230 million in value of its Common Shares at prices between US$5.00 and US$5.75 per Common Share (the "Offer"), which included the option for shareholders to make a proportionate tender. Roivant made a proportionate tender of its Common Shares in the Offer in order to maintain its proportionate ownership of the Common Shares following completion of the Offer. The Offer expired at 5:00 p.m., New York City time, on September 29, 2026. On October 1, 2026, the Issuer announced that it had taken up and accepted for purchase 46,000,000 Common Shares at a purchase price of US$5.00 per Common Share, including 8,967,383 Common Shares tendered by Roivant pursuant to its proportionate tender, for aggregate consideration to Roivant of approximately US$44,836,915. Following completion of the Offer, Roivant continues to beneficially own approximately 19.5% of the outstanding Common Shares.

Number of shares

See rows 7-10 of the cover page to this Amendment No. 14 for information regarding Roivant's power to vote or direct the vote and its power to dispose or direct the disposition of the Common Shares. Except as disclosed in this Schedule 13D, Roivant does not and, to Roivant's knowledge, the Covered Persons do not beneficially own any Common Shares or have the right to acquire any Common Shares.

Transactions

Except as disclosed in this Amendment No. 14, Roivant has not effected and, to Roivant's knowledge, none of the Covered Persons has effected any transactions in the Common Shares since the last Schedule 13D/A was filed with the SEC on February 25, 2025.

Other persons with an interest

Except as disclosed in this Amendment No. 14, no person other than Roivant has the right to receive, or the power to direct the receipt of dividends from, the proceeds from the sale of the shares to which this Amendment No. 14 relates.

Date ownership ceased to exceed 5%

Not applicable.

Percentage of class

Reporting Person (Roivant) Roivant beneficially owns 29,880,079, or approximately 19.5%, of the Common Shares and has sole voting and dispositive power over such Common Shares. Roivant disclaims beneficial ownership in all Common Shares reported herein, except to the extent of Roivant's respective pecuniary interest therein.

Contracts and arrangements

This Item 6 supplements (but does not replace) Item 6 as set forth in the Schedule 13D. Roivant has entered into a Letter of Transmittal for the sale of the shares sold in the Issuer's issuer tender offer as described in Item 4 of this Amendment No. 14, in the form set forth in Ex-99(a)(1)(ii) of the Issuer's Schedule TO-I filed with the SEC on August 24, 2026.

Filed exhibits

Exhibit 99.1 - Covered Persons