PRE 14A

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, DC 20549

SCHEDULE 14A

INFORMATION REQUIRED IN PROXY STATEMENT

SCHEDULE 14A INFORMATION

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934


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☐		Definitive Proxy Statement

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☐		Soliciting Material Pursuant to §240.14a-12

Aptose Biosciences Inc.

(Name of Registrant as Specified in Its Charter)

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Notice and Proxy Statement

For The

Annual And Special Meeting OF Shareholders

TO BE HELD ON MAY 27, 2025

April , 2025

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Letter from Our Chairman, President, and CEO

Dear All,

Since its inception, Aptose Biosciences has been committed to developing precision medicines addressing unmet medical needs in hematologic malignancies. Aptose defined 2024 with significant advancements in the development of our lead precision therapeutic tuspetinib (TUS), a drug that shows genuine promise in treating large, underserved patient populations in acute myeloid leukemia, or AML. Our singular focus is to combine TUS with the BCL-2 inhibitor venetoclax (VEN) and the hypomethylating agent azacitidine (AZA) to create the TUS+VEN+AZA triple drug cocktail (“triplet”) as an improved frontline therapy for newly diagnosed AML patients that is active across diverse AML populations (mutation agnostic triplet frontline therapy). Indeed, during 2024 we initiated our TUSCANY trial and began treating newly diagnosed AML patients with the TUS+VEN+AZA triplet.

Tuspetinib brings favorable safety and broad activity across AML genetic subtypes to the TUS+VEN+AZA triplet therapy, which already has achieved complete remissions (CRs) in difficult-to-treat and underserved TP53-mutated/CK AML and FLT3-wildtype AML patients, a population that accounts for an estimated 70% of AML cases. This activity differentiates TUS from other drugs in development. This TUS+VEN+AZA triplet therapy study in newly diagnosed AML was supported with robust safety and efficacy data from the TUS single agent dose escalation study and the TUS+VEN doublet APTIVATE study in relapsed or refractory (R/R) AML, both of which were completed during 2024 after treating more than 170 patients. These were remarkable clinical accomplishments by a dedicated team despite challenging and difficult market conditions.

AML is a highly aggressive, deadly, and heterogeneous cancer of the bone marrow and blood, and there is tremendous unmet need for a new therapy that can improve response rates, extend survival, and improve the quality of life of newly diagnosed AML patients. Most AML patients at diagnosis are over the age of 65, and such patients have an expected five-year survival of less than 10%. After newly diagnosed AML patients fail frontline therapies, responses to subsequent salvage therapies in the relapsed or refractory (R/R) setting are limited and provide inadequate survival times. This highlights the need for a more effective triplet combination therapy to increase survival in the frontline setting for all AML patients.

The standard of care (SOC) therapy for newly diagnosed AML patients in the frontline setting includes a doublet combination of venetoclax and a hypomethylating agent (VEN+HMA), such as azacitidine. Current experimental agents added to VEN+HMA to create triplet therapies have achieved notable response rates but are inadequate because of toxicities, the inability to dose VEN and HMAs at the SOC levels, and the limited activity across subpopulations of AML patients. In contrast, tuspetinib is a convenient, orally administered, once daily kinase inhibitor with an excellent safety profile and broad activity across AML populations with adverse genetics. Consequently, we believe tuspetinib is an ideal agent for addition to the VEN+HMA backbone therapy to create a superior triplet (TUS+VEN+HMA) frontline therapy to treat newly diagnosed AML.

Tuspetinib was designed by Hanmi Pharmaceutical as a targeted kinase inhibitor that simultaneously suppresses several key pathways that drive the uncontrolled proliferation of AML cells and that enables AML cells to enter the cell death pathway. This design enables TUS to exert AML cell killing across genetic subpopulations of AML, including those with mutations in TP53, RAS, NPM1, IDH1/2, ASXL1, RUNX1, CSFR and other genes, those with complex karyotype chromosomal aberrations, and those with mutated or unmutated (wild type) FLT3. Yet remarkably, TUS has demonstrated an excellent safety profile across multiple dose levels and has not introduced toxicities often caused by other agents, such as QTc prolongation cardiac toxicity, muscle damage, differentiation syndrome, prolonged myelosuppression, and other toxicities that can lead to drug-related deaths. TUS demonstrates the unusual paradox of being both safe and highly active across a diversity of AML patients.

Because of the safe and broadly active profile of TUS, we’ve heard from key opinion leaders (KOLs) in AML that they have great enthusiasm for tuspetinib’s potential. We believe that tuspetinib can have its greatest AML patient impact as a frontline triplet therapy by improving the response rates, the depth of responses, the durability of responses, the quality of life, and the long-term survival across a diversity of AML patients. Likewise, we heard this same message consistently from major potential pharma partners, and they believe TUS can achieve an estimated $1Bn+ annual commercial impact in the frontline AML setting. The KOLs, potential partners, and our internal team all agree the TUS+VEN+HMA triplet regimen has the potential to become a mutation agnostic and new standard of care for frontline treatment of newly diagnosed AML.

During 2024, Aptose announced that it entered into a Cooperative Research and Development Agreement (“CRADA”) with the National Cancer Institute (NCI), part of the National Institutes of Health. Under the CRADA, the NCI and Aptose plan to collaborate on the clinical development of TUS, an inhibitor of key signaling kinases involved in myeloid malignancies, in the NCI Cancer Therapy Evaluation Program (CTEP) sponsored myeloMATCH trials employing combinations of targeted therapy

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for the treatment of molecularly defined AML and myelodysplastic syndromes (MDS) populations. These trials are expected to be conducted by NCI's National Clinical Trials Network (NCTN), with the participation of the NCI Community Oncology Research Program (NCORP) in the U.S. and Canada.

During 2024, Aptose completed several financings for a total of approximately $37 million to support the TUS-based TUS+VEN+HMA triplet therapy development for AML. We financed corporate activities with cash gleaned from our S-1 Public Offerings, through a Private Placement and a separate $10 million debt facility with our strategic partner Hanmi Pharmaceutical, and through an At-the-Market (or ATM) Facility and a Committed Equity Facility. We continued disciplined financial management of our operations, and we prioritized investments in the tuspetinib clinical program.

Key Goals and Milestones Accomplished During 2024

•

Initiated dosing of TUS+VEN+AZA triplet therapy in newly diagnosed AML patients in TUSCANY trial

•

Executed CRADA with NCI MyeloMATCH for tuspetinib in AML/MDS

•

ASH: Reported CR/Safety from APTIVATE TUS and TUS+VEN trial

•

ASH: Reported dosing accrual from TUS+VEN+AZA triplet therapy trial

•

Raised approximately $37 million with multiple financing instruments

Collectively, I can report that Aptose has executed on several fronts during 2024 and has made significant progress, especially with the TUS+VEN+AZA triplet study in newly diagnosed AML. We especially thank the patients, families and investigators who are participating in advancing our essential work and supporting our efforts to create superior therapeutics. I thank our entire Aptose organization and thank you, my fellow shareholders, for your support and for being part of our journey. Despite trying markets, we remain optimistic and believe we can navigate the challenges of biotechnology development to deliver tuspetinib as an important drug for AML patients and deliver value to investors.

Sincerely,

William G. Rice, Ph.D.

Chairman, President and Chief Executive Officer

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Aptose Biosciences Inc.

Notice of 2025 Annual and Special Meeting of Shareholders

NOTICE IS HEREBY GIVEN that the annual and special meeting (the “Meeting”) of shareholders of Aptose Biosciences Inc. (the “Corporation”) will be held on May 27, 2025 at 10:00 a.m. (Eastern time). The Meeting will be conducted as an online only meeting. There will be no physical location for shareholders and duly appointed proxyholders to attend. Shareholders and duly appointed proxyholders are invited to attend by live webcast accessible directly online at https://meetings.lumiconnect.com/400-334-682-750, where they will be able to listen, vote, and submit questions during the Meeting.

What the Meeting is About

The following items of business will be covered at the Meeting:

receiving the financial statements of the Corporation for the fiscal year ended December 31, 2024, including the auditor’s report thereon;

Proposal No. 1 – electing seven directors to serve until the 2026 Annual Meeting of Shareholders;

Proposal No. 2 – appointment of the Corporation's independent registered public accounting firm to serve as the Corporation's independent auditor for the fiscal year ending December 31, 2025 and to authorize the board of directors of the Corporation (the "Board") to fix their remuneration;

Proposal No. 3 – passing an advisory (non-binding) resolution on the compensation of the Corporation’s named executive officers, as more particularly described in the accompanying proxy statement (the “Proxy Statement”);

Proposal No. 4 – passing an ordinary resolution, the full text of which is set forth in the accompanying proxy statement, approving an amendment to the Corporation’s 2021 stock incentive plan to increase the number of common shares (the “Shares”) reserved for issuance thereunder by 458,126 Shares;

Proposal No. 5 – passing a special resolution, the full text of which is set forth in the accompanying proxy statement, approving the adoption of an amendment to the Corporation’s articles to effect a reverse stock split of the Corporation’s outstanding Shares at a ratio in the range of 1-for- to 1-for- (the “Reverse Stock Split”), such amendment to become effective at an exact ratio and a date to be determined by the Board if the Board considers it to be in the best interests of the Corporation to implement such Reverse Stock Split, all as more particularly described in the Proxy Statement;

Proposal No. 6 - passing a resolution, the full text of which is set forth in the accompanying proxy statement, approving one or more adjournments of the Meeting, if necessary or appropriate, if a quorum is present, to permit the Corporation to complete the search for a successor auditor and/or to permit further solicitation of proxies if there are not sufficient votes at the time of the Meeting to approve Proposals No. 4 and No. 5; and

transacting such other business as may be properly brought before the Meeting.

The shareholders may also consider other business that properly comes before the Meeting or any adjournment of the Meeting. The Proxy Statement provides additional information relating to the matters to be dealt with at the Meeting and forms part of this notice.

You have the right to vote.

You are entitled to receive notice of and vote at the Meeting, or any adjournment, if you are a holder of Shares at the close of business on April 22, 2025.

You have the right to vote your Shares on items 2 through 7 listed above and any other items that may properly come before the Meeting or any adjournment.

The Notice of Meeting, Proxy Statement and the form of proxy will be mailed to you on or about April 30, 2025. Detailed instructions regarding shareholders’ voting process are also available on our website at https://www.aptose.com/investors/news-events/ir-calendar.

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Your vote is important.

If you are not able to attend the Meeting, please exercise your right to vote by signing and returning the enclosed form of proxy to Computershare Investor Services Inc., 100 University Avenue, 8th Floor, Toronto, Canada M5J 2Y1, so as to arrive not later than 5:00 p.m. (Eastern time) on May 23, 2025 or, if the Meeting is adjourned, 48 hours (excluding Saturdays, Sundays and holidays) before any adjournment of the Meeting.


	BY ORDER OF THE BOARD OF DIRECTORS

	William G. Rice, Ph.D. Chairman, President and Chief Executive Officer April , 2025

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IMPORTANT NOTICE REGARDING THE INTERNET AVAILABILITY OF

PROXY MATERIALS FOR THE ANNUAL AND SPECIAL MEETING OF

SHAREHOLDERS TO BE HELD ON MAY 27, 2025.

Our Notice of 2025 Annual and Special Meeting of Shareholders, Proxy Statement and Annual Report to Shareholders are available on the Corporation’s website at https://www.aptose.com/investors/news-events/ir-calendar.

Copies are also available upon written request to the Senior Vice President, Chief Financial Officer, Chief Business Officer and Corporate Secretary (i) at our principal executive and registered office located at 66 Wellington St W Suite 5300, Toronto, Ontario, Canada, M5K 1E6; or (ii) at our executive headquarters located at Suite 120, 12770 High Bluff Drive, San Diego, California, 92130.

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GENERAL INFORMATION ABOUT THE PROXY STATEMENT	1
QUESTIONS ABOUT THE ANNUAL AND SPECIAL MEETING AND VOTING YOUR SHARES	2
CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS	11
VOTING SECURITIES AND PRINCIPAL HOLDERS OF VOTING SECURITIES	11
SHARE OWNERSHIP OF CERTAIN BENEFICIAL OWNERS, MANAGEMENT AND DIRECTORS	12
RECEIPT OF FINANCIAL STATEMENTS	13
PROPOSAL NO. 1—ELECTION OF DIRECTORS	14
Board Recommendation	18
CORPORATE GOVERNANCE	18
Board Mandate	18
Composition and Independence of the Board	18
Directors Skills and Experience Matrix	19
Involvement of Directors with other Reporting Issuers	19
Board Leadership	19
Board Oversight of Risk

IMPORTANT NOTICE REGARDING THE INTERNET AVAILABILITY OF

PROXY MATERIALS FOR THE ANNUAL AND SPECIAL MEETING OF

SHAREHOLDERS TO BE HELD ON MAY 27, 2025.

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SEC Form PRE 14A filed by Aptose Biosciences Inc.