Ms. Susan Pietropaolo reports

LEADING INDEPENDENT PROXY ADVISORY FIRM ISS RECOMMENDS APTOSE BIOSCIENCES SHAREHOLDERS VOTE "FOR" PROPOSED PLAN OF ARRANGEMENT WITH HANMI PHARMACEUTICAL

Institutional Shareholder Services (ISS), a leading independent proxy advisory firm, has recommended that Aptose Biosciences Inc. shareholders vote for a special resolution to approve the previously announced arrangement pursuant to which Hanmi Pharmaceutical Co. Ltd. and HS North America Ltd., a wholly owned subsidiary of Hanmi, will acquire all of the issued and outstanding common shares of Aptose that are not currently owned or controlled by the Hanmi purchasers or their respective affiliates.

In making its recommendation that shareholders vote for the arrangement resolution, ISS noted:

"The offer price represents a premium to the unaffected price. In addition, the initial market reaction was positive, no other bidders have presented a superior proposal and there has been no public opposition from non-Hanmi shareholders. The cash form of consideration provides liquidity and certainty of value to Aptose shareholders."

ISS also recommended approval of a continuance that will result in the company continuing from a corporation governed under the Canada Business Corporations Act (CBCA) to a corporation continued under the Business Corporations Act (Alberta) (ABCA). According to ISS, shareholder rights under the two statutes are largely similar and there would be no adverse impact on such rights on account of the continuance.

Transaction details

As previously disclosed in the company's news release dated Nov. 19, 2025, upon the completion of the arrangement, Aptose shareholders, other than the Hanmi purchasers and their respective affiliates that hold any common shares, will receive $2.41 in cash per common share, which represents a premium of 28 per cent over Aptose's 30-day VWAP (volume-weighted average pric) of $1.88 on the Toronto Stock Exchange (TSX) and Aptose will have continued from a corporation incorporated under the CBCA to a corporation continued under the ABCA.

Details of the meeting

A special meeting of shareholders to seek approval of the arrangement and the continuance, has been reconvened to March 31, 2026, at 11 a.m. ET (the reconvened meeting). The reconvened meeting will be held virtually via live audio webcast. The original meeting was postponed to address comments raised by the United States Securities and Exchange Commission (SEC) on the company's transaction statement on Schedule 13E-3, as amended. The record date for the meeting was the close of business on Feb. 24, 2026.

Aptose has prepared and filed with the SEC a definitive proxy statement for the reconvened meeting. A copy of the proxy statement has been mailed to all shareholders of the company. The proxy statement, form of proxy, letter of transmittal, as well as Schedule 13E-3, as amended, will also be available for download under Aptose's profile on SEDAR+ and EDGAR.

On Dec. 12, 2025, Aptose obtained an interim order from the Court of King's Bench of Alberta authorizing the holding of the meeting and matters relating to the conduct of the meeting.

Shareholders encouraged to vote ahead of the proxy deadline

Aptose's board of directors unanimously recommends that the shareholders vote for the special resolutions approving the continuance and the arrangement resolution at the reconvened meeting.

The proxy voting deadline is 11 a.m. Eastern Time on Friday, March 27, 2026. Shareholders are encouraged to vote well in advance of the deadline to ensure their vote is submitted in a timely manner.

All shareholders who wish to attend the reconvened meeting must follow the procedures set out in the proxy statement. Shareholders who are unable to attend the reconvened meeting are strongly encouraged to complete, date, sign and return the form of proxy (in the case of registered shareholders) or voting instruction form (in the case of non-registered shareholders) provided with the meeting materials so that as many shareholders as possible are represented and vote at the reconvened meeting.

The completion of the transaction is subject to satisfaction of customary closing conditions, including court approval and approval of the TSX.

Shareholder questions and voting assistance

Aptose has retained Morrow Sodali (Canada) Ltd. to assist the company in connection with shareholder communications and proxy solicitation. Shareholders who have questions or require voting assistance may contact Sodali & Co. at:

Call toll-free (North America):  1-833-711-4830

Call collect outside North America:  1-289-695-3075

E-mail:  assistance@investor.sodali.com

About Aptose Biosciences Inc.

Aptose Biosciences is a clinical-stage biotechnology company committed to developing precision medicines addressing unmet medical needs in oncology, with an initial focus on hematology. The company's small molecule cancer therapeutics pipeline includes products designed to provide single agent efficacy and to enhance the efficacy of other anti-cancer therapies and regimens without overlapping toxicities. The company's lead clinical-stage compound TUS is an oral kinase inhibitor that has demonstrated activity as a monotherapy and in combination therapy in patients with relapsed or refractory AML and is being developed as a front-line triplet therapy in newly diagnosed AML.

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